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INTERNATIONAL SYMPOSIUM ON PHOTOELECTRONIC DETECTION AND IMAGING 2011 | 24-26 MAY 2011
International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819201 (2011) https://doi.org/10.1117/12.910111
This PDF file contains the front matter associated with SPIE Proceedings Volume 8192, including the Title Page, Copyright information, Table of Contents, Introduction, the Symposium and Conference Committees listing, and the Cooperating Organizations page.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819202 (2011) https://doi.org/10.1117/12.904062
The ability of lidar technology to provide three-dimensional elevation maps of the terrain, high precision distance to the
ground, and approach velocity can enable safe landing of robotic and manned vehicles with a high degree of precision.
Currently, NASAis developing novel lidar sensors aimed at the needs of future planetary landing missions.These lidar
sensors are a 3-Dimensional Imaging Flash Lidar, a Doppler Lidar, and a Laser Altimeter. The Flash Lidar is capable of generating elevation maps of theterrain toindicate hazardous features such as rocks, craters, and steep slopes. The
elevation maps, which arecollected during the approach phase of a landing vehicle from about 1 km above the ground,
can be used to determine the most suitable safe landing site. The Doppler Lidar provides highly accurate ground relative
velocity and distance data thusenablingprecision navigation to the landing site. Our Doppler lidar utilizes three laser
beams that are pointed indifferent directions to measure line-of-sight velocities and ranges to the ground from altitudes
of over 2 km.Starting at altitudes of about 20km and throughout the landing trajectory,the Laser Altimeter can provide
very accurate ground relative altitude measurements that are used to improve the vehicle position knowledge obtained from the vehicle'snavigation system. Betweenaltitudesof approximately 15 km and 10 km, either the Laser Altimeter
or the Flash Lidar can be used to generate contour maps of the terrain, identifying known surface features such as craters to perform Terrain relative Navigation thus further reducing the vehicle's relative position error. This paper describes the
operational capabilities of each lidar sensorand provides a status of their development.
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Haris Riris, Kenji Numata, Steve Li, Stewart Wu, James Abshire, Graham Allan, William Hasselbrack, Mike Rodriguez, Jeffrey Chen, et al.
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819203 (2011) https://doi.org/10.1117/12.900870
Many fundamental questions about planetary evolution require monitoring of the
planet's atmosphere with unprecedented accuracy at both high and low latitudes, over both
day and night and all seasons. Each planetary atmosphere presents its own unique challenges.
For the planets/moons that have relatively low surface pressure and low trace gas
concentrations, such as Mars or Europa, the challenge is to have enough sensitivity to
measure the trace gas of interest. For Earth, the challenge is to measure trace gases with very
high precision and accuracy in the presence of other interfering species.
An orbiting laser remote sensing instrument is capable of measuring trace gases on a global
scale with unprecedented accuracy, and higher spatial resolution that can be obtained by
passive instruments. For Mars, our proposed measurement uses Optical Parametric
Amplifiers (OPA) and Integrated Path Differential Absorption (IDPA) in the 3-4 um spectral
range to map various trace gas concentrations from orbit on a global scale. For earth, we
propose to use Erbium Doped Fiber Amplifier technology (EDFA) and IDPA at 1.57 and
OPA at 1.65 μm to measure carbon dioxide and methane concentrations respectively.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819204 (2011) https://doi.org/10.1117/12.900978
It has been pointed out that globally hermatypic corals in coral reefs have been seriously damaged in recent years, and it
is predicted that such damages will expand in area in the future. It is important to monitor corals globally, in detail, and
over long-term periods, for preservation of the marine environment and biodiversity. The spot-check method, one of the
major coral monitoring methods, is operated by snorkelers or divers, and therefore, its operation is limited by the seastate,
and its monitoring areas are often for specific observation points. On the other hand, the satellite remote sensing,
another major coral monitoring methods, can cover composite coral reef areas, but the image resolution is a few meters,
and it is not possible to monitor small size coral colonies and deep sea areas.
The boat-based fluorescence imaging lidar system has been developed to complement these coral monitoring methods.
This system obtains linear coral observation data along the boat track, and makes it possible to build a cooperative coral
monitoring network. Since most hermatypic corals have fluorescent proteins, living tissues can be monitored using the
blue-to-green fluorescence from UV excitation. It is possible to observe the UV-excited fluorescence images from live
coral even in the daytime, by the UV excited fluorescence imaging lidar. Additionally, laser bathymetry is also possible
by time-of-flight measurement. We have succeeded in observing the pseudo-coral fluorescent images and depths down to
30 m depth at the testing basin. Secondly, we have succeeded in observing the live coral fluorescent images and their
depths by the lidar system using a glass-bottom-boat at Taketomi island, Okinawa, Japan. The system summary and
observed data are reported in this paper.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819205 (2011) https://doi.org/10.1117/12.900108
In the previous study, we have introduced the concept of the
real-time 3D imaging LADAR (LAser Detection And
Ranging) using linear array receiver. In this paper, we demonstrate a long range, high resolution, and high speed 3D
imaging using the developed system. The system consists of
in-house-made key components. The linear array receiver
consists of the previously reported APD array and the ROIC array assembled in one package. We newly developed the
transmitting optics using pupil divide method which realizes a uniform illumination on a target. By combining these
devices with the one dimensional fast scanner, we realized a 256 × 256 pixels range imaging with a on-line frame rate
of more than 10 Hz at a distance of more than 1 km.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819206 (2011) https://doi.org/10.1117/12.903299
High concentration Er3+-Yb3+-codoped fiber laser (EYFL) can provide high gain 1.54μm laser emission. In this paper,
simulation of the lasing operation of an ultra-short Er33+Yb3+-codoped phosphate fiber laser (EYPFL) was introduced
using the theoretical models of high gain ultra-short EYFL with considering the energy transfer upconversion processes.
The dependence of output power on fiber length, Er3+-Yb3+ concentrations and output coupler reflectivity are
investigated numerically. Based on the numerical analysis, when the pump power is below 800 mW, fiber length of
9.5-13 cm, Er3+ concentration of 1.0-1.4×1026/m3 and Yb3+ concentration of 0.3-0.8×1027/m3 are desirable to optimize the
performances of EYPFL. Finally, the experimental results of a 11.6 cm EYPFL with the maximum output power of 230.4
mW is demonstrated in short straight cavity configuration with slope efficient of 45.7%.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819207 (2011) https://doi.org/10.1117/12.901057
Lidar detects atmospheric parameters by transmitting laser pulse to the atmosphere and receiving the backscattering
signals from molecules and aerosol particles. Because of the small backscattering cross section, lidar usually uses the
high sensitive photomultiplier and avalanche photodiode as detector and uses photon counting technology for collection
of weak backscatter signals. Photon Counting enables the capturing of extremely weak lidar return from long distance
throughout dark background by a long time accumulation. Because of the strong solar background, the signal-to-noise
ratio of lidar in the daytime could be greatly restricted, especially for the lidar operating at visible band where solar
background is prominent. Narrow band-pass filters must therefore be installed in order to isolate solar background noise
at wavelengths close to that of the lidar receiving channel, whereas the background light in superposition with signal
spectrum limits an effective margin for SNR improvement. This work propose a high spectral resolution lidar prototype
operating at the Fraunhofer lines, the invisible band of solar spectrum, to achieve photon counting under intense solar
background. The laser transmitter is an optical parametric oscillator pump by 355 nm Nd:YAG laser and is tuned to the
dark line by the Magnesium atom of the solar atmosphere by which nearly 90% of solar radiation is absorbed. The
prototype provides some theoretical references for optimized design of photon counting lidar in visible band with the
comparable SNR at night, which may contribute to the research on diurnal variation of atmosphere and to the operational
observation of lidar.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819208 (2011) https://doi.org/10.1117/12.894602
Relay mirror is used to track ground-based beacon accurately in space optical communication. It is unreliable to track the
beam by the ordinary quadrant. DBA video tracker applies avalanche photo diode quadrant to enhance, which can
improve the performance of the relay mirror tracking system. However, the sight line disturbance followed is
unacceptable. By the continuous designs we present the scheme of enhanced video tracker with high-passed high
bandwidth quadrant, and it is proved that it is successful for the relay mirror experiment.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819209 (2011) https://doi.org/10.1117/12.895422
Improving performance of beam uplink propagation in the relay mirror system has become a very lively area of scientific
research. In recent years, many methods were proposed. But most related researches only concerns power coupling
efficiency. We propose that both power coupling efficiency and the non-uniformity of the received beam should be
considered. Model of the relay mirror system is established. With this model, damage effect of the system is theoretically
analyzed in detail. Performances of uplink propagation with optimizations using different evaluation functions are
calculated. Results show that uplink propagation with optimization using power coupling efficiency as the evaluation
function can't get the optimal performance. For the 25km-altitude relay mirror system, performance of uplink
propagation decreases instead of increases with optimization using power coupling efficiency as the evaluation function.
The coming results show that taking the product of power coupling efficiency and the influence factor induced by the
non-uniformity of the received beam as the evaluation function of the uplink propagation process is reasonable.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81920A (2011) https://doi.org/10.1117/12.895428
Since the water resource is being seriously polluted with the development of the human society, the monitoring of the
available water resource is an impending task. The concentration of the dissolved organic matter, oxygen and inorganic
salt in water can be checked by means of some methods, e.g. electrolysis, electrochemical method, colorimetry. But
because some drawbacks are existed in these methods, the laser-induced fluorescence (LIF) spectrophotometry method is
adopted into this paper. And a novel LIF spectrophotometer for water quality monitor (WQM) is designed. In this WQM,
the 3rd harmonic of the Q switched Nd:YAG laser is used as the induced fluorescence light-source. And for the
splitting-light system of the spectrophotometer for WQM, in order to improve the resolution and light-passing efficiency,
a novel volume holography transmissive(VHT) grating is used as the diffraction grating instead of the plane or
holography grating. Meanwhile, the linear CCD with combined data acquisition (DAQ) card is used as the fluorescence
spectral detection system and virtual instrument (VI) technology based on LabVIEW is used to control the spectral
acquisition and analysis. Experimental results show that the spatial resolution of the novel spectrophotometer for WQM
is improved, its resolution can reach 2nm. And the checking accuracy of this WQM is higher than others. Therefore, the
novel LIF spectrophotometer for WQM has the potential value in the water quality monitoring and biochemical
application.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81920B (2011) https://doi.org/10.1117/12.896065
A method computing the absorption efficiency with the difference between pump power entering the thin disk and pump
power transmitted through the disk is introduced. Compared with directly computing the absorbed power, the method
presented here needs much less computation to achieve the same accuracy, making it possible to compare much more
absorption efficiency values at higher accuracy with a few parameters varied within certain ranges. Nonabsorption loss
values were calculated with absorption coefficient, array distance and round disk radius varied within certain ranges.
Results of calculation showed that the nonabsorption loss generally increases with increasing array distance, decreases
with increasing round disk radius and decreases with increasing absorption coefficient. The method introduced by this
paper presents a theoretical reference for the optimal design of thin disk lasers.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81920C (2011) https://doi.org/10.1117/12.896273
A method of phase retrieval based on windowed Fourier transform has been proved to be one of the most effective
algorithms for carrier fringe patterns. The calculation speed of windowed Fourier transform ridge (WFTR) is time
consuming. The accuracy and calculation speed of phase retrieval using WFTR depend on the scanning frequency
interval, but how to determine a proper frequency interval is still a problem. In this paper we see WFTR as a response of
a linear time-invariant system. Then we calculate the system response function by means of numerical analysis, finding
that there is always an area of zero phase response near the local frequency and its width nearly equals to the width of the
main lobe of the amplitude response function. This means a system response function with bigger main lob width and
fast decay rate allows a bigger frequency interval and less calculation times. These operations only increase a little error
at the edge of the fringe pattern, but give a fast calculation speed. Finally we compare the carried fringe pattern phase
with a standard phase extracted by the four-step phase-shifting algorithm.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81920D (2011) https://doi.org/10.1117/12.896697
This paper introduces a novel kind of E-O Q-switched Nd:YVO4 compact laser with ultra-narrow pulse width. In this
paper, the general equations describing Q-switched laser operation are given and the factors about cavity length, laser
gain medium, the loss inner resonator and pump energy to influence the laser pulse width are analyzed theoretically. These parameters greatly optimized experiment. The fiber-coupled laser-diode end-pumped laser we developed
simplifies the conventional structure of E-O Q-switched lasers. The cavity length is effectively reduced to 19mm to narrow the pulse width. The pulse width of 1.049ns is obtained and the single pulse energy reaches to 0.32mJ. This 1
nanosecond laser has the advantage in reliable and outstanding performance with simplified structure. Most importantly, we investigated the performance of an innovative RTP crystal in the Q-switched laser with high repetition frequency. It was experimentally proven that this narrow pulse width laser can operate with high repetition frequency because of the
novel Q-switched crystal RTP with great performance. Both theoretical analysis and experiment data demonstrate that sub-nanosecond pulses can also be produced with E-O Q-switching technique. Thus, this technique can be widely applied.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81920E (2011) https://doi.org/10.1117/12.896797
The imaging ladar provides precise and accurate 3D information. In addition, it is independent from external lighting
conditions. On the other side, visible image has high resolution, color information and texture-maps. Through fusing the
ladar image and visible image in effect, we can get a 3D and color image, which is in favor of image processing. This
thesis describes a particular system to solve the image fusing problem. First, measure error of the ladar was revised in
this paper. Then, corresponding relationship of the ladar image and visible image was obtained by a method of camera
calibration. The ladar image and visible image were fused by the technology of texture mapping in the end. The result of
experiment demonstrate that this method of image fusion is workable and efficient.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81920F (2011) https://doi.org/10.1117/12.897127
To produce high-quality, low-scattering optical interference coatings for laser-gyro application, substrates with extremely
smooth surfaces are required for deposition. For successful production of qualified mirrors, characterization of substrates
before coating is essential. Light scattering has been used for decades to characterize the surface roughness of optical
components. Its application in characterizing the surfaces of transparent substrates, commonly used for deposition, is
difficult due to the low scattering of high-quality substrates and the scattering contribution of substrates' back surface
and volume scattering. Light scattering characterization of transparent substrates for laser-gyro application has been
studied in this paper. It has been found that collecting objective is more propitious to eliminate volume scattering and
scattering from back surfaces of substrates than integrating sphere and more appropriate to characterize superpolished
transparent surfaces of substrates for laser-gyro application. Collecting objective whose N.A. is 0.4 has been designed in
ZEMAX. Careful analysis shows that scattering from back surfaces and volume scattering from points with axile
distances to the front surface more than 1.5 millimeters can be eliminated completely. To solve the drift problem of PMT
used for probing scattering light, specific structure of collecting system has been designed, so that scattering light and
reflecting light can strike on the same PMT orderly. It has been found that the drift problem of PMT could be solved with
this setting, so that the stability of the scattering measurement system over long time span could be improved greatly and
its practicability in engineering has been ensured.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81920G (2011) https://doi.org/10.1117/12.897279
In recent years, laser polishing has been widely used in the field of material surface processing. Studies show that in the
polishing process, the laser energy directly affects the effectiveness and efficiency, and usually when the incident laser
energy is determined, the laser fluence on the material surface can be characterized by the laser spot area. This paper
presents the system designed for laser spot size of real-time detection and three dimensional control on basis of digital
signal processor (DSP) and field programmable gate array (FPGA) processing technology.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81920H (2011) https://doi.org/10.1117/12.897336
The velocity and impacting position of a flying projectile is usually measured by optical screen target at the range of
shooting range measurement. In order to improve the situation of low sensitivity and the small effective sensor area in
available optical screen, a laser screen target is put forward in this paper, which takes the line structured light laser as the
transmitter and the silicon PIN photodiode as the receiver. In present paper the performance of the optical screen
transmitter and the distribution of light energy in the whole screen are analyzed, and the graph of distribution simulated
by MATLAB is given. The sensitivity of the effective sensor area is analyzed and calculated. With the verification on air
gun projectile, the design of the optical screen in the effective sensor area within 5m × 5m was able to detect air gun
projectile. The result demonstrated that this optical screen woks with high sensitivity, high stability and reliability, and
the effective sensor area of the measuring can reach to 10m × 10m for the rifle projectile measurement. The mechanical
structure and the signal process circuit can also be used on multiple optical screens target and the large space detection
for early warning.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81920I (2011) https://doi.org/10.1117/12.897371
Traditional phase shifting shape measurement techniques not suitable for dynamic measurement because it need a certain
number of pieces of fringe pattern. In this paper, the basic principle of the fringe projection shape measurement
technique was introduced, the method of single fringe pattern phase extraction by Hilbert transform was discussed, and
conducted three-dimensional shape measurement tests. Experimental results show that 3-D shape measurement can be
achieved by Hilbert transform phase-shifting, and it suitable for dynamic measurement.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81920J (2011) https://doi.org/10.1117/12.897822
With the avalanche photodiode (APD) as the receiver, we have studied the timing error influence on performance of the
optical pulse PPM system after analyzing the channel model of the atmospheric laser communication, and respectively
obtained the relationship between the normalized timing error and PWE in the strong and weak turbulent environment. In
addition, we obtained the influences of parameters such as the scintillation index, APD average gain and the levels of
PPM modulation on performance of the optical pulse PPM system by simulation when there are timing errors in the
system.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81920K (2011) https://doi.org/10.1117/12.897878
The flying velocity of fragment is a key parameter to evaluate the damage power of warhead. Due to
small volume, large amount, irregular shape, high velocity, arbitrary flying direction, wide distribution
and serious measuring environment, it's very difficult to measuring the velocity of fragment. We adopt
two fan-shaped laser screens combining with retroreflective cooperation objects to construct detect
module, and break through the laser screen transmitting-receiving integration optoelectronic detection
technique. The signals of the fragment flying through the screens are collected, saved and processed by
software. The system can realize a real-time, non-contact, reproducible, all-weather optoelectronic
measurement for fragment velocity during warhead explosion. Using the developed prototype, we
successfully acquired the analog signals when five fragments flying through two laser screens for
certain an explosion warhead, and obtained their velocities which can be regarded as instantaneous
velocities at the midpoint between two screens. The result validates the accuracy of the method and its
feasibility of engineering application.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81920L (2011) https://doi.org/10.1117/12.898563
The detection of amplitude distribution of the conventional time average holography is realized through the
reconstructed image intensity, however, no satisfactory results can be often obtained because there are many noise
influences such as speckle noise. As there are only two values for the phase of the first kind of zero-order Bessel
function, namely 0 and μ, we can determine the amplitude distribution through the reconstructed field phase. And this
method is better than the conventional, but it takes a longer time. This paper presents a new method that through
introducing the shearing principle to vibration measurement of time average digital holograph, we can detect the
amplitude distribution rapidly by directly using the shearing interferogram to find out the phase stepping region, and this
method need no phase unwrapping operation. Simulation computation and experiment results show that the time new
method need for vibration measurement is shorter than that of reconstructed field phase, and the measurement effect is
better than that of reconstructed image intensity.
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Huili Wang, Yunying Wang, Shengtao Chen, Yi Qi, Huanying Liu
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81920M (2011) https://doi.org/10.1117/12.898745
As a ship passed by, a long and wide wake is left and can last for a long time. The optical characteristic of the wake
is quite different from the water because of the abundant bubbles in the wake. Bubbles in the wake scatter and absorb
light to alter its intensity and polarization state. As an important character of light, the polarization of scattering light of
bubbles and water can be used to detect bubbles in the wake and can provide important information to the design of lidar
detecting system. In this paper the theoretical and experimental study of polarization characteristic of water and bubble
scattering echo are presented. The polarization of scattering light of bubbles and water were calculated by Stokes vector
and Muller matrix. The echoes of water and wake bubbles simulated by ceramic tube were measured in laboratory by
adjusting the angle of analyzer. The measurement results are given in the paper including the echoes of water and
bubbles at different distances. The results show that by adjusting the angle of analyzer, the strong backscattering of water
is compressed greatly but that of bubbles decreases a little. Take advantage of this characteristic the measurement range
of detecting device can be broadened to some extent.
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Zhi-peng Zhang, Ke-yong Wang, Jia-hao Deng, Yan Hai
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81920N (2011) https://doi.org/10.1117/12.898758
Laser imaging techniques have advantages for EMI (Electro Magnetic Interference) immunity and abundant image
information. This contribution describes the research activity on the scannerless laser imaging detection technique using
direct detection aimed at laser fuze applications. The technique using a pulsed laser to illuminate the target and a focal
plane array can be used as a receiver. The range information is achieved by means of a direct time of light measurement.
Information about the reflectivity of the target is gathered by recording the amplitude of the received pulse. In this paper
a high-repetition-frequency, narrow pulse semiconductor laser floodlight emitting system is designed; corresponding
optics is used to generate the homogenously illuminated FOI (field of illumination). The echo of laser is collected by
receiving optical system fed to focal plane array. Some experiments were done with the emitting and receiving systems
that had been designed. Experiments show the validity and rationality of this method. The scannerless structure is robust
and provides instantaneous snapshot-type imaging. Avoiding any moving mechanical parts, scannerless laser imaging
system have distinct characteristics such as small, compact, high frame rate, wide field of view and high reliability. It is
an optimal approach to realize laser imaging fuze.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81920O (2011) https://doi.org/10.1117/12.898941
3D range-gated imaging with stepping delay is a novel technology developed in recent years. 3D timing control signal
based on delay line and logical AND gate technology is proposed innovatively in order to satisfy the distance precision
of centimeter of 3D imaging in complex background. 3D timing control signal is produced through FPGA nanosecond
timing generation module and picosecond timing adjustment module. Simulation and experiment show that the delay
precision of the timing signal designed in this paper is 150 picoseconds, and the narrowest pulse width is close to the
limitation of TTL signal (1ns level). The timing control signal designed in this paper can be widely used in 3D
range-gated imaging because of its high timing control precision, compact construction and flexible parameter setting.
Keywords: range-gated, picosecond, timing control, FPGA, delay line
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81920P (2011) https://doi.org/10.1117/12.899043
The elasticooptic effect of crystal is analyzed by the method of index ellipsoid. The relationship between the stress along
the optical axis of trigonal crystallographic system and the refractive index is then established. Considering the optical
anisotropic property of crystal and very small change of refractive index with the stress, the optic low coherence
interferometry technique can be extended to measure the refractive index of anisotropic material, beause of its high
spatial resolving power. Moreover, all polarization-maintaining fiber Michelson interferometer for measuring the
elasticooptic coefficient of crystal has been sucessfully constructed. Unlike a common fiber low coherence
interferometer, all the components are connected via polarization-maintaining fibers. Besides, an improved method
using low coherence interferometry and Michelson interferometer to measure group refractive index is introduced, using
grating displacement sensor and all polarization-maintaining fiber to greatly increase the displacement precision of
scanning mirror. The refractive index change of LiNbO3 crystal under different external force has been measured and the
elasticooptic coefficient is determined. It is shown that the elasticooptic coefficients P13 and P33 of LiNbO3 crystal are
0.110 and 0.089, respectively. The precision reaches 0.001.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81920Q (2011) https://doi.org/10.1117/12.899106
A simple way to approach the problem of counteracting the phase aberrations induced by thermal deformations in a beam
control system is advanced and the influence of wavefront pre-compensation on correcting the phase shifts is proved by
experiments. The thermal deformations of a Si reflector irradiated by a circle-sharp laser beam are simulated, and the
phase aberrations of emitted laser are calculated. In order to overcome the effects of phase aberrations, the conjugation
wavefront pre-compensation of incident laser is studied theoretically and experimentally. There are three works in this
paper. Firstly, the thermal deformation of a mirror was simulated by using ANSYS Mechanical APDL application.
Secondly, on the base that the phase shifts has been calculated, the complex amplitude distribution of the outgoing laser
was calculated by using a space ray method of geometrical optics and light diffraction theory. Finally, the influence of
wavefront pre-compensation on emitted laser had studied experimentally with a scaled model in laboratory. The results
show that the uneven distribution of phase shifts which is induced by inhomogenous thermal deformations greatly
distorts the wavefront of the emitted laser. The beam quality of emitted laser has been ameliorated when a conjugation
phase is been placed on the incident beam.
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Hai-bo Zhang, Li-hua Cao, Ai-hui Geng, Yan Li, Ru-hai Guo, Ting-feng Wang
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81920R (2011) https://doi.org/10.1117/12.899165
Laser pulse code is an anti-jamming measures used in semi-active laser guided weapons.
On account of the laser-guided signals adopting pulse coding mode and the weak signal processing,
it need complex calculations in the frequency measurement process according to the laser pulse
code signal time correlation to meet the request in optoelectronic countermeasures in semi-active
laser guided weapons. To ensure accurately completing frequency measurement in a short time, it
needed to carry out self-related process with the pulse arrival time series composed of pulse arrival
time, calculate the signal repetition period, and then identify the letter type to achieve signal
decoding from determining the time value, number and rank number in a signal cycle by Using
CPLD and DSP for signal processing chip, designing a laser-guided signal frequency measurement
in the pulse frequency measurement device, improving the signal processing capability through the
appropriate software algorithms. In this article, we introduced the principle of frequency
measurement of the device, described the hardware components of the device, the system works and
software, analyzed the impact of some system factors on the accuracy of the measurement. The
experimental results indicated that this system improve the accuracy of the measurement under the
premise of volume, real-time, anti-interference, low power of the laser pulse frequency measuring
device. The practicality of the design, reliability has been demonstrated from the experimental point
of view.
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Hong-Xia Wang, Chao Sun, You-zhang Zhu, Hong-hui Sun, Pan-shi Li
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81920S (2011) https://doi.org/10.1117/12.899292
Based on the Mie scattering theory and the gamma
size distribution model, the scattering extinction parameter
of spherical fog-drop is calculated. For the transmission
attenuation of the laser in the fog, a Monte Carlo simulation
model is established, and the impact of attenuation ratio on
visibility and field angle is computed and analysed using the
program developed by MATLAB language. The results of
the Monte Carlo method in this paper are compared with
the results of single scattering method. The results show
that the influence of multiple scattering need to be
considered when the visibility is low, and single scattering
calculations have larger errors. The phenomenon of
multiple scattering can be interpreted more better when the
Monte Carlo is used to calculate the attenuation ratio of the
laser transmitting in the fog.
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Mingjun Wang, LeLi Ying, Jiadong Xu, Ningjing Xiang, Deng Rong
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81920T (2011) https://doi.org/10.1117/12.899298
The experimental measurement and image processing methods are combined to study the visible light scattering characteristics from target in this paper. The Xenon lamp is utilized as a visible light source which incidence the target with rough surface and measure the characteristics of light scattering. The original experimental images must be
obtained by light receiver and data gathering. The gray value is integrated in the target regions so that the whole visible
light scattering characteristics have been analyzed. As a researching example, two kinds of bigger and smaller simple
targets include clubs, cylinders and their combinations are discussed, which dimensional proportion of them is 1:2. The scale-model ratio of the backward light scattering from target is proportional to the square of dimensional scale. The important of our works is that the integral gray value can make known the illumination of the detected target, which is
the important parameter in visible light detection. It is significance to detect the target in the applications with the visible
light.
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Feng Yu, Tingwu Ge, Jing jing Dai, Wenqi Zhang, Pu Wang, Zhiyong Wang
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81920U (2011) https://doi.org/10.1117/12.899378
Super-continuum(SC) is widely used in coherent photography technology,
optical spectroscopy analysis, interferometry, etc because of its flat and broad
high spatial coherence and high power. Super-continuum generation could be realized
on theory by ultra-short pulse laser getting through the high nonlinear medium,
accompany with self-phase modulation (SPM), stimulated Raman scattering (SRS),
four-wave mixing (FWM). With the development of fiber technology, Yb-doped
ultra-short pulse fiber laser, which has high peak power, high optic-to-optic efficiency,
compact structure and small volume was elected as the pump source, and high
nonlinear photonic crystal fiber (PCF) as the nonlinear medium for SC. In this paper,
steady and self-starting mode-locked pulse ring cavity fiber laser based on the
nonlinear polarization rotated effect as seed source is obtained. Taking Yb-doped
double-cladding fiber as the gain medium, through MOPA structure, the 80mW signal
was amplified to 3.1W, with 1064nm wavelength, 41.3MHz repetition frequency and
50ps impulse duration; the amplified mode-locked pulse was coupled into a 10m PCF,
with 1040nm zero dispersion point, to generate 1.5W super-continuum by fusing
method, during which the key parameters like discharge time, discharge interval,
loss are seriously optimized to keep the fusing quality well. The whole system is all
fiber structure, which is much higher than conventional free-space coupling way in
both conversion efficiency and stability.
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Zhong-guo Li, Chuan-xiang Yi, Shu-guang Dong, Ying-lin Song
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81920V (2011) https://doi.org/10.1117/12.899384
The third-order optical nonlinearities of semiconductor CdS are investigated using 4f nonlinear image technique with
phase object at 745 nm. The measurement method is based on the 4f coherent optical processor system in Fourier optics.
The nonlinear parameters of sample can be verified by numerical fitting the nonlinear image at the output plane of 4f
system which obtained by a CCD camera. Using one-single-shot, the two-photon absorption coefficient β and nonlinear
refraction index n2 of the CdS which arranged at the Fourier plane are determined simultaneously. The experimental
results shows CdS has reverse saturable absorption and
self-defocusing effect at 745 nm, indicating this material is a
good candidate for future photonics applications.
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Ri-na Wu, Qin Dai, Bin Yan, Yan-juan Liu, Song-ning Xu, Wei Quan
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81920W (2011) https://doi.org/10.1117/12.899385
The lasing action of dye doped cholesteric liquid crystal (CLC) cell was investigated in this work. A planar state was
prepared by antiparallel rubbing process ITO glasses with polymide layer coating. The dye doped cholesteric liquid
crystal mixture was used by mixing a laser dye DCM, a chiral agent CB15 and a nematic liquid crystal TEB30A. A
second harmonic Q-switched Nd:YAG pulsed laser (λ=532nm) was used as the pumping source. A sharp peak was
measured at 611 nm in the cell-normal direction and cell-plane direction after reaching threshold pump energy. The least
full width of half maximum (FWHM) were about 10 nm and 12 nm. The optical structure of the device was investigated
upon applied voltage. The results show that planar state of the CLCs is a prerequisite for the generation of lasing
emission. So laser emission attributed to the photonic band gap (Bragg mode) in the cell-normal direction in which the
helical axis exists. Due to the waveguide structure formed by the liquid crystal sandwiched between glass substrates
(ne=1.522, no=1.692>ng=1.50), quasi-in-plane leaky lasing modes exist in the cell-plane direction.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81920X (2011) https://doi.org/10.1117/12.899450
To take a large and high-grade hologram, have been numerous scientific workers' interested topics. Since the stability of
the holographic plate, objective table's stability, object's stability, optical elements' stabilities, etc, aren't easily
supervised and controlled precisely, the laser holographic technique has progressed at a slow pace.
Precise micropressure measuring system, an application of laser technology, is introduced as a method for monitoring
holographic plates' stability. This system firstly brings the pressure sensor into the laser holographic experiments, and
uses the soft Kingview to design the programs for controlling the pressure sensor, so that the system can real-time
monitoring and real-time adjusting the laser holographic plates' stability. Being verified by experiments, this experiment
has achieved good results, for example, making a larger hologram, saving the time taken from the original 1-2 days to
present of 0.5-1.5 hours, that is to say those above-mentioned measures raise the success rate of making large holograms
to some extent.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81920Y (2011) https://doi.org/10.1117/12.899460
Coherent Doppler wind lidar has found widespread applications in aerospace, aviation, space-based remote sensing,
atmospheric observation, and so on. In this paper, a china-made coherent Doppler wind Lidar prototype using all fiber optical components has been described and recent examples of wind measurement capability are provided.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81920Z (2011) https://doi.org/10.1117/12.899461
Owing to the notable advantages over range, resolution and accuracy, satellite-borne high-resolution 3D imaging lidar
has found widespread applications in aerospace reconnaissance, deep-space detection, earth observation, disaster
evaluation, and so on. Based on the principle of 3D laser imaging, the typical satellite-borne high-resolution 3D active
imaging lidar systems are reviewed and the development trend is analyzed. Some conclusions can be drawn that operating mechanism of direct detection would be transferred to coherent detection and diode-pumped solid state laser
would be transferred to fiber laser. In addition, advanced synthetic aperture and array detection technology should be
adopted for higher range resolution.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819210 (2011) https://doi.org/10.1117/12.899486
Image matching is a fundamental aspect of many problems in computer
vision applications. Many of these applications have real-time constraints. Recently there has
been much interest in object and view matching using local invariant features and descriptor.
Center surround extrema (CenSurE) features have aroused wide interest because of the high
compute efficiency. Due to its linear scales, the filter response signal is very sparse, can't
acquire high repeatability. So, we modified the center-surround detectors (CenSurE) using
logarithmic scale sampling, and to detect the features of image interpolation, obtained the
subpixel level of accuracy. The results of image matching experiments and theory analyzing
demonstrate that improved center-surround detectors are more stable and repeatable than
CenSurE. At the same time, we proposed a new rapid descriptor based on gradient of the
summed image patch, called GSIP. The results of image region matching experiments
demonstrate that the GSIP descriptor has better distinctiveness than the state-of-the-art SURF
descriptor, and achieves a 2 fold speed increase. The local feature and descriptor present
here can be used widely in real-time view matching fields, including motion tracking, solving for
3D structure from multiple images, and robots visual navigation.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819211 (2011) https://doi.org/10.1117/12.899521
Lidar and CCD camera have the excellent ability of capturing 3D information of objects and they are widely used for 3D
modeling. The effective fusion of 3D lidar image and CCD camera color image can give better results. The major
problem of fusion lidar data and CCD camera data is the coordinate calibration between them. In consideration of the
traits of lidar and CCD camera, a special 3D calibration object was designed, and an improved coordinate calibration
method was proposed, which fits a plane using principal components analysis and can highly improve the calibration
precision. After the lidar and CCD camera has been calibrated, the data they captured are transferred to fusion computer
by USB and network. Data processing and display are achieved in fusion software written in C++ and OpenGL.
Experiment results show that our real time image fusion system gives good result in the 3D reconstruction of objects, the
imaging rate of the system can get to 5 frames per second.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819212 (2011) https://doi.org/10.1117/12.899569
The phase singularities of Gaussian beams propagating through an astigmatic aperture lens are studied.
Numerical calculation results are given to illustrate how the astigmatism affects the evolution behavior of
phase singularities. It is shown that with increasing astigmatic coefficient, the phase singularities shift not
only towards the aperture lens, but also towards the z axis. The reorganization process of phase singularities
of focused Gaussian beams in the presence of astigmatism with increasing truncation parameter is
illustrated by numerical examples.
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Xin-zhong Li, Yu-ping Tai, Zhao-gang Nie, Li-ping Zhang, Ya-jun Wang
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819213 (2011) https://doi.org/10.1117/12.899580
A selection method of subset size in sub-pixel displacement registration is proposed. The algorithm principle of
interpolation, fitting of distribution of the correlation coefficients and gradient-based methods are introduced. Using
computer-simulated speckle images, their precision and efficiency depending on the subset size are studied. The optimal
method and subset size are presented in various measurement ranges, which offer measuring bases for sub-pixel in
DSCM.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819214 (2011) https://doi.org/10.1117/12.899585
Fibroblast is the main part in the loose connective tissue and differentiates from the mesenchymal cell when it is in embryo. It exhibits highly reproducible growth kinetics and reproducible healing dynamics in the scratch-wound assay and the height of it could show this prediction. In order to measure the height of these cells, we construct an
interferometer measuration system. As we all know, the interference pattern should be unwrapped first, there are plenty of methods that are under research. In this paper we want to find out a typical methods that could be used in living cell's interference pattern during image processing, and also we can get the conclusion that how to use the method and why it
is fit to unwrap the phase of cells. There are mainly three parts in this paper: Firstly, we have designed an Interference
system which can be used to get the interference pattern, here we used multiphase interference microscope to measure the cell height. Secondly, a typical method which is based on Goldstein's branch cuts algorithm were used to guide the way that how the phase is unwrapped, this method is the most efficient way to phase unwrapping, and it could induct the unwrapping path through using the branch cut method which could get rid of the residues as much as it could be. As a comparison, we also used some other methods to find different results. Such as the quality-guided path following phase unwrapping; and the Costantini phase unwrapping. Finally, we analyzed the results of the three-dimensional model of the
cell surface topography, as a result of the various noises during the experiment, all these unwrapping methods above can't eliminate all the residues and noises, but compared with the other results, the Goldstein's branch cut method has the
fittest advantages, it gives the most fluent topography of the living cells.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819215 (2011) https://doi.org/10.1117/12.899586
Ladar system simulation is to simulate the ladar models using computer simulation technology in order to
predict the performance of the ladar system. This paper presents the developments of laser imaging radar
simulation for domestic and overseas studies and the studies of computer simulation on ladar system with
different application requests. The LadarSim and FOI-LadarSIM simulation facilities of Utah State University
and Swedish Defence Research Agency are introduced in details. This paper presents the low level of
simulation scale, un-unified design and applications of domestic researches in imaging ladar system
simulation, which are mostly to achieve simple function simulation based on ranging equations for ladar
systems. Design of laser imaging radar simulation with open and modularized structure is proposed to design
unified modules for ladar system, laser emitter, atmosphere models, target models, signal receiver, parameters
setting and system controller. Unified Matlab toolbox and standard control modules have been built with
regulated input and output of the functions, and the communication protocols between hardware modules. A
simulation based on ICCD gain-modulated imaging ladar system for a space shuttle is made based on the
toolbox. The simulation result shows that the models and parameter settings of the Matlab toolbox are able to
simulate the actual detection process precisely. The unified control module and pre-defined parameter settings
simplify the simulation of imaging ladar detection. Its open structures enable the toolbox to be modified for
specialized requests. The modulization gives simulations flexibility.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819216 (2011) https://doi.org/10.1117/12.899592
A novel acoustical-vibration signal detection system based on laser Doppler is proposed. The system is based on the
M - Z interferometer optical system, and used more adaptive piezoelectric ceramics modulation and demodulation
system to restore signal. The whole system satisfies the requirements of non-contact, remote, high sensitivity and
anti-interference. It has the advantages of strong stability, compact light path, low cost and easy miniaturization
compared with heterodyne interferometer based on Acoustical Optical Modulator (AOM). At last the influence of the
laser power fluctuations (frequency instability and amplitude instability) on the system is analyzed theoretically.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819217 (2011) https://doi.org/10.1117/12.899601
Electro-optically tunable two-dimensional hexagonal Talbot phase array which are based on congruent Lithium
Niobate crystal and MgO doped Lithium Niobate crystals are investigated, respectively. Experimental results show that a
variety of pattern can be generated under different voltage bias and fractional distance. Numerical simulation was studied,
and the experimental results agreed with simulation.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819218 (2011) https://doi.org/10.1117/12.899643
We propose a surveillance photonic fence for night remote intrusion detection, especially in bad environmental
conditions. The photonic fence is established by the synchronization of a pulsed infrared laser and a gated imaging sensor.
Since the wavelength of the laser is invisible, the photonic fence is also invisible. Only when targets pass the fence, their
image information can be collected. Objects and backgrounds out of the fence are all filtered directly which decreases the
complexity of image processing about target extraction. For the fence, its location can be easily adjusted by the delay
time between the laser pulse and the gate pulse, and its thickness can be set by changing the gate time and the laser pulse
width. Furthermore, target space information can also be estimated in terms of the range information of the photonic
fence.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819219 (2011) https://doi.org/10.1117/12.899652
With the increase of on-orbit manipulations and space conflictions, missions such as tracking and capturing the target
spacecrafts are aroused. Unlike cooperative spacecrafts, fixing beacons or any other marks on the targets is impossible.
Due to the unknown shape and geometry features of non-cooperative spacecraft, in order to localize the target and obtain
the latitude, we need to segment the target image and recognize the target from the background. The data and errors
during the following procedures such as feature extraction and matching can also be reduced. Multi-resolution analysis
of wavelet theory reflects human beings' recognition towards images from low resolution to high resolution. In addition,
spacecraft is the only man-made object in the image compared to the natural background and the differences will be
certainly observed between the fractal dimensions of target and background. Combined wavelet transform and fractal
dimension, in this paper, we proposed a new segmentation algorithm for the images which contains complicated
background such as the universe and planet surfaces. At first, Daubechies wavelet basis is applied to decompose the
image in both x axis and y axis, thus obtain four sub-images. Then, calculate the fractal dimensions in four sub-images
using different methods; after analyzed the results of fractal dimensions in sub-images, we choose Differential Box
Counting in low resolution image as the principle to segment the texture which has the greatest divergences between
different sub-images. This paper also presents the results of experiments by using the algorithm above. It is demonstrated
that an accurate texture segmentation result can be obtained using the proposed technique.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81921A (2011) https://doi.org/10.1117/12.899739
Testing system based on computer-generated holograms(CGHs) can achieve high accuracy of aspherical measurement,
this paper studies a new method for testing convex aspheric surface-two CGHs. This method has an advantage in
resisting interference and needing no huge assistance surfaces. For a convex hyperboloidal mirror, such a testing system
has been designed and optimized in Zemax with the testing accuracy of prior to 0.015λ, and all of other disturbing rays
image outside of aperture with a radius of 0.8mm. Finally, the system errors are analyzed in detail and the results show
that this system can guarantee the testing accuracy of aspherics. In addition, this testing system can also measure off-axis
aspherics and free-form surfaces.
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Xiao-qing He, Ai-hua Gao, Shang-bin Hu, Zhi-guo Lu
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81921B (2011) https://doi.org/10.1117/12.899748
In order to meet the high demand of the entire technology processing, the error compensation method is usually used to
correct them and is premised on a good understanding of error sources and the law of the errors. In this paper, based on
the theories of Collins's Integral and Collins's EIKONAL Function and the MATLAB software, we simulated and
calculated the spatial distribution of optical beam in the cavity of the ring laser gyro under the resonator's maladjustment
caused by the technology processing. From the simulation results, we can get that to the small-gain lasers, the same
amount of disorders in the different structures have different effects on the spatial distribution of the beam, and the
structures using the spherical mirrors relatively have the small impact on the beam; under the same disorder in the same
cavity shape, the signal light and the calibration light which are respectively detected from the mirror M1 and M4 are
different; under the same structures, different mirrors with the same amount of disorder will cause the different beat
frequency difference; because of the disorders, the spot centers of clockwise and counterclockwise waves happen shift
and will seriously affect the normal operation of the laser gyro if the imbalance reaches a certain degree. This work has a
guiding role in the mirror adjustment of the laser gyros' technology processing, and has a reference value to the survival
rate of the laser gyros and the improvement of measurement accuracy.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81921C (2011) https://doi.org/10.1117/12.899872
A cascaded all-fiber amplifier was set up to investigate stimulated Brillouin scattering (SBS) suppression with
phase-modulation (PM) in our experiment. With a modulation index of π / 2 , the SBS threshold power of the modulated
amplifier can be enhanced with a factor of 3.5 compared with the unmodulated single frequency amplifier. In high power
level, we demonstrate a 275 W all-fiber amplifier, where the SBS threshold enhancement factor is larger than 2.2
compared with the unmodulated case with SBS threshold power of 126 W. Further enhancing the output power is limited
by available gain fiber and pump powers in this case.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81921D (2011) https://doi.org/10.1117/12.899874
We achieve a surprisingly exact agreement between the simulation results and the experimental observations (J. C.
Travers et al. Opt. Express 16, 14435-14447(2008)) of visible supercontinuum (SC) generation pumped by a 400W
single mode continuous wave (CW) fiber laser. The propagation of CW field in photonic crystal fibers (PCF) is
numerically simulated by solving the generalized nonlinear Schrödinger equation with the adaptive split-step Fourier
method for high accuracy; moreover, we apply the method of averaging the generated spectra in many simulations to
approach the experimental results. Our simulations confirm that the extension of SC toward short wavelengths is due
to the trapping of dispersive waves by redshifted solitons.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81921E (2011) https://doi.org/10.1117/12.899883
A set of testing system has been designed to measure the transmitting performance of 1.06μm laser emission passed
through various aerosol media. The system includes a semiconductor-pump laser emitter with high power, a laser power
detecting system, a piece of A/D collection card and a computer with special software for data treatment. The emitter can
continuously export 10W 1.06μm laser emission. The diameter of the laser beam at the aperture is 4mm and the beam
divergence angle is smaller than 2mrad. The precision of the power meter is about 0.001W within 20W. The power
detector can translate the power data into simulation voltage signal and transmit it to the A/D card. The software is
applied to get the data of laser power from the A/D card and translate it into numerical signal to analyze or calculate by
computer. The power curve may be drawn while peak value and average power may be analyzed and calculated by the
program for engineering design or scientific research. Furthermore, the transmitting performance or attenuation laws of
1.06μm laser emission passed through various media may be quantitatively measured or analyzed by collecting
background power and sample power after transmitted through a kind of medium. As an example, the transmitting
performance of 1.06μm laser emission passed through water fog has been quantitatively measured. By the result, the
1.06μm laser emission is easy to be attenuated by water fog and the attenuation effect depends upon the concentration of
the aerosol, optical length and other factors.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81921F (2011) https://doi.org/10.1117/12.899997
Based on the nonlinear three optical waves of coupling theory, the walk-off angle, effective nonlinear
coefficients and the interaction length of wavelength of 1064nm and 532nm were calculated numerically under the
condition of second class phase matching of the LBO crystals. In the phase matching range, the bigger the effective
nonlinear coefficient and the smaller walk-off angle between 1064nm and 532nm beams, the higher frequency
conversion efficiency. When the fundamental frequency light was an ideal Gaussian beam, the conversion efficiency
improved with the crystal length increasing in the case of a particular power. And then, the conversion efficiency is
limited by the fundamental frequency light was absorbed and the walk-off angle was increased with the crystal length
increasing.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81921G (2011) https://doi.org/10.1117/12.900005
A signification characteristic is found by analyzing lensless Fourier digital hologram and synthetic aperture holography
that is the imaging surface of reconstructed image of lensless Fourier digital hologram just is focus plane of positive lens
that is unrelated with wavelength of restruction and recording and their ratio. The nature is propitious to resolve the
problem of DMD display caused by unstable holographic imaging surface. Zero order diffraction image is focused on
nearby center of focal surface and imaging zone is rapidly contracted that largely improved quality of reconstructed
image. Meanwhile, position of holographic reconstructed image is not to be altered when parallel moving lensless
Fourier digital holography on the holographic image plane that is easier to improve hologram duty cycle, DMD
availability and quality of reconstructed image with theory of synthetic aperture that attained by single illumination.
According to this analysis, a new method is proposed that combine lensless Fourier digital holography with synthetic
aperture that could improve quality of DMD reconstructed image. We provided laboratory results and verified all theory
analysis that totally proved the method is available and feasible.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81921H (2011) https://doi.org/10.1117/12.900102
To develop a practical fiber laser hydrophone, demodulation method to get the wavelength shift of the fiber laser
hydrophone is a key technology. A novel scheme for demodulating the phase shift is proposed to eliminate the affect of
the three unsymmetrical outputs from 3×3 coupler. A special polarization-insensitive unbalanced Michelson fiber
interferometer based on the 3×3 coupler is employed to transpose the wavelength shift into phase shift of the
interferometer. The interferometer just has two outputs. A certain length of the fiber in an arm of the interferometer is
wrapped onto a PZT tube to get a high frequency phase modulation signal whose amplitude is bigger than π rad, so the
direct and alternate item of the two outputs from the interferometer can be gotten. The two outputs from the
interferometer are detected by photoelectrical detectors, and the digitized acquisition data from the detectors are
processed by Labview program to demodulate the phase shift. The gains of the two outputs are adjusted real-time to get
two symmetric signals after their direct items were subtracted, and the two symmetric signals are processed through
differentiator and cross-multiplier to demodulate the acoustic pressure signal. The sensitivity experiment shows that the
new demodulation scheme can get a steady output and the phase output is linear to the pressure applied on the fiber laser
sensor when the outputs from the interferometer are unsymmetrical. The amplitude fluctuate of the phase output is less
than 5% when the fiber laser hydrophone is under stable acoustic pressure at a frequency point.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81921I (2011) https://doi.org/10.1117/12.900104
To develop a practical fiber laser hydrophone, demodulation method to get the wavelength shift of the fiber laser
hydrophone is a key technology. A homodyne coherent demodulation scheme utilizing a 3×3 coupler has the advantage
of passive detection without phase or frequency modulation in the reference arm and wide dynamic range. But the
amplitude of phase output from the passive homodyne coherent demodulation system based on a 3×3 coupler for fiber
laser hydrophone is instable during a lake test. To solve this problem, the principle of the passive homodyne phase
demodulation scheme based on a 3x3 coupler for the fiber laser hydrophone is investigated and a digital demodulation
system is built. A unbalanced Mach-Zehnder fiber interferometer based on the 3×3 coupler is employed to transpose the
wavelength shift into phase shift of the interferometer. Through theoretical analysis and simulation calculation, the
relations between amplitude discrepancies and the phase differences with the phase output are finally educed. The
theoretical analysis and simulation calculation shows that the amplitude discrepancies and the phase differences of the
three outputs from the interferometer result in the amplitude instability of phase output. To solve these problems, we can
get three symmetrical outputs by adjusting the gains of the three outputs. Both the simulation calculate and the
underwater acoustic experiment show that the phase output of homodyne coherent demodulation system based on a 3x3
coupler can be steady by adjusting the gains of the three outputs, when the 3×3 coupler is asymmetric.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81921J (2011) https://doi.org/10.1117/12.900119
To investigate the influence of atmospheric turbulence on the imaging of SAL,
numerical simulation of phase screens is a an effective means. But the widely-used
spectral approach which generate phase screens following the Kolmogorov spectrum
by using spectrum inverse transform lacks in the low frequency because of which
low-frequency modification is indispensable and computation enlargement is
unavoidable. Another way of generating phase screen based on the fractal
characteristics is introduced in the paper. The phase screen obtained in this way agrees
well with theoretical results from turbulent statistical characteristics both in low and
high frequency region besides the computation is less. Detailed pictures of monolayer
and multilayer random phase screens are given. The calculated multilayer random
phase screens are used to simulate the real atmospheric turbulence. At last the image
of point target is implemented with SAL in strong, mediate and weak atmospheric
turbulence by numerical simulation under vertical side-looking strip-mode. The
results show that the atmospheric turbulence can severely affect the azimuth resolution of the SAL image and with the increase of the atmospheric turbulence, the
distortion of the SAL image deteriorates.
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Lei Wang, Zhi-yong Xu, Qi-heng Zhang, Hua-chuang Wang, Xue-gang Yu, Rui-jie Nie
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81921K (2011) https://doi.org/10.1117/12.900130
A new, simple and compact experimental laser scanning imaging system is introduced for underwater imaging, and the
characteristics of the system are analyzed in this paper. The system consists of the illuminator, optical scanning system,
optical receiving system, narrow band filters, high-sensitivity gated image sensor, synchronous control and data
acquisition system and power supply and cooling system. The illuminator is a lump-pumped, Q-switched, frequency
doubled Nd:YAG pulsed laser operating at 532 nm with a frequency of 50 Hz. The receiver is a self-made gated intensified
charge coupled device (ICCD). As a result, gated super Gen-II image intensifier and PAL format charge-coupled device
(CCD) camera are assembled to meet the requirements. The coupling gated ICCD has a sensitivity of approximated 10-5lx,
and the minimum gate width can reach to 40 ns. And a set of scanning structure which only uses one mirror is used in the
experimental system. In addition, the performance parameters are listed. Finally, the detection capabilities of the imaging
system are theoretically analyzed in typical seawater. The analysis indicates that the detection depth of the system can
reach to 16 m in the clear seawater.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81921L (2011) https://doi.org/10.1117/12.900161
The photorefractive adaptive optical heterodyne detection system (PAOHDS) is proposed. The dynamic properties of
mutually pumped phase conjugate (MPPC), the key technology to the PAOHDS, are studied theoretically. The
three-dimensional distribution of MPPC refraction index grating in time and length axis is simulated numerically. The
dependence of dynamic properties of MPPC on the intensity of the fanning light is presented.The stronger the intensity
of the fanning light is, the less response time for MPPC is. The dependence of dynamic properties of MPPC on the
coupling strength is presented. The greater the coupling strength is, the less response time for MPPC is. These results
provide theoretical basis to reduce response time of PAOHDS.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81921M (2011) https://doi.org/10.1117/12.900170
Modulated lidar is proved efficient to suppress backscatter noise and enhance target contrast. In this paper relationships
between pulse parameters and performance of modulated lidar were fully analyzed. There are three key parameters for
laser pulse: modulation frequency, modulation depth and pulse width. Theoretical models were built for the three
parameters and they are analyzed both in time domain and in frequency domain. It is concluded from experiment results
that modulated lidar reaches to its optimal performance when setting modulation frequency of laser pulse to 2GHz,
modulation depth to 0.5 and pulse width between 10ns and 20ns.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81921N (2011) https://doi.org/10.1117/12.900182
In this report, we mainly focus on the dynamic of the transient thermal effect of the C70/toluene at nanosecond
time-domain. We use the time-resolved pump-probe system based on 4f coherent imaging system with phase object with
nanosecond laser pulse at the wavelength of 532nm.By changing the delay time, we can get different linear and nonlinear
image. So the dynamic process of the transient thermal can be studied. In the experiment, we choose 5ns, 8ns and 10ns,
and found the nonlinear refractive index arises by the delay time.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81921O (2011) https://doi.org/10.1117/12.900186
With the rapid development of semiconductor technology and laser technology, a kind of proximity fuze named
pulsed laser proximity fuze has been applied. Compared with other fuzes, pulsed laser proximity fuze has high ranging
precision and strong resistance to artificial active interference. It is an important development tendency of proximity fuze.
The paper analyze the characteristic of target echo of laser signal, and then make theoretical analysis and calculation on
the laser signal transmission in the smog. Firstly, use the pulse width of 10ns semiconductor laser fuze to do typical
targets experiment, to get the echo information of target distance is 5m; then to do smog interference experiment, by
comparing the pulse width amplitude and backscattering signal amplitude of laser fuze in simulation and experiment,
analyzing the effect of anti-clutter, providing the evidence for the subsequent of circuit of signal amplification and
processing.
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Jun-qi Liu, Jian-yan Chen, Wan-feng Liu, Wan-hong Guo, Yu-chao Jiang, Feng-qi Liu, Lu Li, Li-jun Wang, Zhan-guo Wang
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81921P (2011) https://doi.org/10.1117/12.900189
We designed and demonstrated a series of surface emitting quantum cascade lasers
within the range of 4.5-9.0μm with different kinds of grating structure. The 2-order
Bragg grating structure were exposed on top of the materials by means of optical
lithography or holography and realized by deeper wet chemical etching. Many of
these devices exhibit high performance in single-mode characteristics, operation
temperature, and far field characteristics. These results give a cheerful prospect for the
sensing and medical diagnosis application in the near future.
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Zhong-quan Nie, Ying-lin Song, Yu-xiao Wang, Xue-ru Zhang, Jun-yi Yang
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81921Q (2011) https://doi.org/10.1117/12.900221
Using comparison based on a nonlinear-imaging thchnique with phase object have been proposed to measure the
cubic nonlinear refractive index. The equal thickness interference can be performed at the output of parallel double 4f
coherent imaging system. Lastly, we draw a conclusion that the ratio of the material's nonlinear refractive index equals to
the inverse ratio of the laser intensity of two optical paths while the interference stripes don't shift any more. It is a
powerful and sensitive method for nonlinear optical investigation that worth doing deeper research.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81921R (2011) https://doi.org/10.1117/12.900222
This paper presents a novel algorithm to extract signal area of range-gated images under the EBE effect. Besides
the histogram information, this algorithm uses average gray value information to select threshold with iterative
processing. With average gray value information, the edges of signal area can be segmented out accurately. The
algorithm can handle images under the impact of EBE effect, reduce the noise in the images and segment the
objects from the noise area effectively without many morphological operations which keeps the certain figure from
distortion. Experiment result shows that the algorithm is effective to the signal areas extraction of images under
EBE effect, signal areas can be segmented out accurately.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81921S (2011) https://doi.org/10.1117/12.900227
This paper presents imaging result of computer simulation using a modified Radon-Fourier transform algorithm to
reconstruct images from reflective tomography data. Since the signal returned is reflected off the illuminated outer
surface of an opaque target, only information about the exterior of the target can be obtained, and the images
reconstructed using reflective tomography techniques is an outline view of the target cross section. The projection
p(r,φ ) and p(r,φ + 180°) contain different information about the target surface, and will lead different Fourier
estimates along the same line through the origin based on the standard Fourier-Slice tomography theorem. Here, using
the functional similarity between transmission tomography and reflective tomography, we add the collinear reflective
projections to become corresponding transmissive projections before Fourier transform. Then the target can be
reconstructed from the Fourier domain using the same operations in transmission tomography. The computer simulation
result demonstrates the effectiveness of this modified algorithm to reconstruct image in reflective tomography using the
diffuse reflection model (lamberts body). Future research will include the development of image reconstruction based on
this modified algorithm for targets with much more complicated reflective characters.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81921T (2011) https://doi.org/10.1117/12.900228
As one of the most successful optical correlation recognizers, hybrid optoelectronic joint transform correlator (HOJTC)
has received more and more attraction than the purely electronic way in the field of target detection and recognition. It
primarily because that HOJTC has the advantages of optics as well as those of electronics. This kind of combination
determines that the performance of HOJTC is closely related to optical configuration of system and digital image
processing technology. For the stability of optical part, a lot of efforts concerning image processing methods have been
made in recent years for improving the power of recognition of HOJTC. Edge contours play a decisive role in target
detection. In order to obtain adequate contour feature of target, the solution of edge extraction based on wavelet
multi-scale product is proposed. Normalized maximum and argument of each point could be defined utilizing wavelet
coefficient of image. Both of them contain the relation of coefficient product between each scale. Edge points
synthesized the information of multi-scale are extracted by searching local maxima along the direction of gradient. The
way adopted fully exploited the character of multi-resolution of wavelet. Simulation experiments and optical experiments
indicate that the energy of correlation peaks is obviously enhanced after the original image is processed by wavelet
multi-scale product, and it successfully realizes detection and recognition of infrared target.
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Yang Liu, Jin Yu, Tianzhuo Zhao, Xue Zhang, Zhongwei Fan
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81921U (2011) https://doi.org/10.1117/12.900230
Designed a system for the high gain laser pre-amplifier to evaluate the image quality. The system uses 4f imaging
principle and Kepler type telescope was choiced, it has two advantages: avert optical distortion and eliminate aberration
in the measurement system. Combined with the location of the lens inside of pre-amplifier such as the spatial filter , the
near field imaging structure was designed. The structure can be reduced to 11.9 times the beam image, and clearly passed
the image to the CCD target surface. The location of first positive lens focus is the location of far field image. In this
article, one laser pre-amplifier was measured. The average measured near field modulation M=1.34, the average
measured far field diffraction limit is 2.94. Experiments show that the stability of measuring system is less than±5%, it
can meet the measurement requirements of ICF laser pre-amplifier parameters. Use this system we can discover the
problem during the design and installation. There is great meaning for develop of laser pre-amplifier in ICF for further.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81921V (2011) https://doi.org/10.1117/12.900235
Latent fingerprints present a considerable challenge in forensics, and noninvasive procedure that captures a digital image
of the latent fingerprints is significant in the field of criminal investigation. The capability of photography technologies
using 266nm UV Nd:YAG solid state laser as excitation light source to provide detailed images of unprocessed latent
fingerprints is demonstrated. Unprocessed latent fingerprints were developed on various non-absorbent and absorbing
substrates. According to the special absorption, reflection, scattering and fluorescence characterization of the various
residues in fingerprints (fatty acid ester, protein, and carbosylic acid salts etc) to the UV light to weaken or eliminate the
background disturbance and increase the brightness contrast of fingerprints with the background, and using 266nm UV
laser as excitation light source, fresh and old latent fingerprints on the surface of four types of non-absorbent objects as
magazine cover, glass, back of cellphone, wood desktop paintwork and two types of absorbing objects as manila
envelope, notebook paper were noninvasive detected and appeared through reflection photography and fluorescence
photography technologies, and the results meet the fingerprint identification requirements in forensic science.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81921W (2011) https://doi.org/10.1117/12.900251
In this paper, we report on a CW 980 nm double clad photonic crystal fiber laser pumped by the CW
915 nm diode laser. The photonic crystal fiber used in the experiment has a core diameter of 40 μm,
inner clad of 200 μm, an absorption coefficient of about 3 dB/m at 915 nm. The fiber length is 40 cm.
In the single-end output experiment, an output power of 1.2 W with a slope efficiency of 15% has been
achieved. To the best of our knowledge, it was the first time for the 980 nm Yb-doped fiber laser by
using the flexile large-mode-area double-clad photonic crystal fiber.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81921X (2011) https://doi.org/10.1117/12.900262
Current research on Laser Scanner often focuses mainly on the static measurement. Little use has been made of
dynamic measurement, that are appropriate for more problems and situations. In particular, traditional Laser Scanner
must Keep stable to scan and measure coordinate transformation parameters between different station. In order to make
the scanning measurement intelligently and rapidly, in this paper ,we developed a new registration algorithm for
handleheld laser scanner based on the positon of target, which realize the dynamic measurement of handheld laser
scanner without any more complex work. the double camera on laser scanner can take photograph of the artificial target
points to get the three-dimensional coordinates, this points is designed by random coding. And then, a set of matched
points is found from control points to realize the orientation of scanner by the least-square common points
transformation. After that the double camera can directly measure the laser point cloud in the surface of object and get
the point cloud data in an unified coordinate system. There are three major contributions in the paper. Firstly, a laser
scanner based on binocular vision is designed with double camera and one laser head. By those, the real-time
orientation of laser scanner is realized and the efficiency is improved. Secondly, the coding marker is introduced to
solve the data matching, a random coding method is proposed. Compared with other coding methods,the marker with
this method is simple to match and can avoid the shading for the object. Finally, a recognition method of coding maker
is proposed, with the use of the distance recognition, it is more efficient. The method present here can be used widely in
any measurement from small to huge obiect, such as vehicle, airplane which strengthen its intelligence and efficiency.
The results of experiments and theory analzing demonstrate that proposed method could realize the dynamic
measurement of handheld laser scanner. Theory analysis and experiment shows the method is reasonable and efficient.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81921Y (2011) https://doi.org/10.1117/12.900263
For the detection and recognition of dangerous space debris, a novel detection scheme with space-based or spaceborne
ladar is presented in this paper. In the scheme, the semiconductor laser of 1.55 micron is adopted as the emitter source
and a chirped intensity modulation waveform is utilized to obtain the range and radial speed of dangerous space debris.
To improve the SNR and further the maximum detectable range, the simplified coherent optical processing (i.e.
heterodyne processing) is proposed. The proposed ladar system has the advantage of low cost, low complexity and high
flexibility and can meet the requirement of spaceborne detection.
This paper is mainly comprised of three parts. In the first part, the schematic diagram of the proposed laser radar system
is shown and the main components are introduced in brief; and then the operation principle and processing flow are
formulated in detail. In the second part, some operating parameters (such as transmitting power, modulation bandwidth
and duration time) and system performance (such as SNR, detection range and resolution) are analyzed. In the final part,
the detection of the typical dangerous space debris is simulated numerically, and some conclusions are made as well.
The theoretic analysis and numerical simulation prove that the proposed detection scheme is effective and feasible.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81921Z (2011) https://doi.org/10.1117/12.900305
A laboratory calibration method for transmissometer is proposed. It takes advantage of numerical simulation to
evaluate the precision of calibration method. The numerical simulation is coded taking advantage of matlab. The
calibration errors of different visibility is studied. And the influence of turbulence to calibration of transmissometer is
studied.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819220 (2011) https://doi.org/10.1117/12.900308
A complete set of ultra-long focal length measurement system based on the principle of Talbot effect and moiré fringe
technology has been developed. The numerical simulation is coded taking advantage of matlab. The errors deduced by
errors of parameters of ultra-long focal length measurement is studied. And the focal length variance and fluctuation
deduced by turbulence and wavefront of incident laser beam is studied.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819221 (2011) https://doi.org/10.1117/12.900311
The product surface roughness measurement occupies an important position in the manufacturing process of the
industrial product. The laser speckle image can be used for the non-contacted measurement. The Speckle images are
produced by the reflected and scattered light beams from rough surface through free-space to observing plane when laser
illuminates the object surface. Statistical distribution of speckles depends on the microscopic structure of the rough
surface and can be used to distinguish the surface roughness. Firstly, for the existence of the noise and redundancy in the
laser speckle image, the PCA(principal component analysis) method is utilized in the image processing. After extracting
the principal components in the original image matrix, the reconstruction image which removed noises and irrelevances
was earned. Secondly, the fractal features of reconstruction images were extracted by using the Double Blanket Method.
The fractal dimension of the reconstruction image was analyzed under the moving window with optimum size to obtain
the fractal dimension histogram. By comparing the histogram with the surface roughness, the obvious correlations of the
frequency point distributing of the fractal dimension histogram and the product surface roughness was shown. On these
bases, the multi-scale fractal features were extracted for the single-scales limitation. So, the method of product surface
roughness measurement based on the fractal feature of the laser speckle image was given by the research. The measure
system set-up of the method is simple, fast, and not sensitive to change of circumstance and vibration. Hence, it has great
potential for application to in-process measurement.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819222 (2011) https://doi.org/10.1117/12.900313
The CO2 differential absorption lidar (DIAL) technique have advantages such as high vertical and horizontal resolution,
the ability to acquire simultaneous species and aerosol profiles, day and night coverage and no dependence on external
radiation. An all solid-state l.5 μm CO2 differential absorption coherent lidar was designed in the paper. The key
technology of the system such as high precision laser wavelength control, echo correlation detection were solved the
tunable-diode-laser (newfocus model 6330) was selected as the laser source. The reference CO2 gas pool was selected as
for absorption calibration. The modulated laser signal was sent through the gas pool and detected by the detector. By
observing the frequency of output voltage of the detector, the wavelength of the on-laser was locked. The experiment
showed the precision of the laser wavelength control was under 0.1pm which is narrower than the CO2 absorption band
width. The aim of the echo coherent detection is promoting the SNR of the Lidar. By the polarization separating and
collecting for the echo and local-oscillator signal, the problem of polarization matching between the echo and seed was
solved. The balanced detector was selected to achieve the balanced detection, which remarkably eliminated the affection
of the local-oscillator noise. The laboratorial experiment for the lidar was carried out to detect the CO2 inside the gas
pool. The analysis of the experiment data showed the CO2 detection sensitivity of the system is up to the 25ppm pre
kilometer long path.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819223 (2011) https://doi.org/10.1117/12.900490
The quality of the range image obtained by laser radar will directly influence the target profile reconstruction and the
target identification, and the quality of the range image is mainly determined by the parameters of laser radar system. As
a result, this paper concentrates on discussing the effect of laser radar's parameters on the quality of range image. To
evaluate the quality of range image quantitatively, two parameters, the mean squared error of range (R-MSE) and peak
signal noise ratio of range (R-PSNR), are introduced and a simulation program is developed to study the influence of
system's parameters on the range imaging quality. The results show that for a given pulse width, there has an optimal
bandwidth and threshold level, that make the range image has better image quality. Above results have important
significance to optimize the parameter design of laser radar.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819224 (2011) https://doi.org/10.1117/12.900510
Interference image processing is the key technology of optical interference measurement. Using high resolution image
sample system to recognize the interference fringe, which substituted the traditional method measured by technological
worker, is improving the measurement accuracy of thin film thickness. This paper introduced the problems on automatic
interference fringe processing in absolutely measurement based on laser interference, digital image processing
technology. The image acquisition of the SiO2 film and the pre-processing of interferogram was performed. Decimal part
of the interference fringes is obtained.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819225 (2011) https://doi.org/10.1117/12.900512
We report on the amplification of 21ps pulses up to 10W average output power in both a conventional
ytterbium-doped large-core double-clad fiber and photonic crystal fiber (PCF). The picosecond fiber
amplifier system consists of a mode-locked Nd:YVO4 oscillator and a diode-pumped double-clad
large-core ytterbium-doped fiber. a passively mode-locked (SESAM) Nd:YVO4 oscillator is used as the
picosecond seed source, which has repetition rate of 93 MHz, pulse duration as short as 19.2 ps at 1064
nm and an average power of 380 mW. At first, conventional double clad fiber is used as the amplifier
medium, which has an inner cladding diameter of 250 μm and the active core diameter of 30 μm. The
absorption coefficient of this fiber is as high as 9 dB/m at 976 nm. Secondly, PCF with an inner
cladding diameter of 200 μm, the active core diameter of 40 μm is chosen for the amplifier with the
same absorption coefficient as the conventional double clad fiber. For these two kinds of fiber
amplifiers, both more than 10 W amplified output power have been achieved. Since lager mode area
double clad ytterbium-doped fiber and photonic crystal fiber have been chosen in the amplifier, which
would lead to a reduced nonlinearity, spectral broadening due to SPM is extensively suppressed.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819226 (2011) https://doi.org/10.1117/12.900533
The calculation for the spectrum of beams passing through a multi-apertured ABCD
optical system has not been finished in any personal computer when the aperture number is more
than a certain value. By means of the expansion of the window function of the hard-edge aperture
into a finite sum of complex Gaussian functions, an approximate analytical expression for the
spectrum of polychromatic Gaussian beams passing through a multi-apertured ABCD optical system
is derived and illustrated with numerical examples. The numerical results find an agreement with
those by straightforward integral of the cross-spectral density function, but the computing time is
strongly reduced.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819227 (2011) https://doi.org/10.1117/12.900542
In this paper, dual-wavelength digital holography is demonstrated by both numerical simulation and experiment.
Simulations were done for two wavelengths of 500 nm and 550 nm. The objects are a wedge prism with a height of 2.5
μm and four abrupt steps. Three-dimensional (3D) reconstruction profiles of the original objects are obtained in the
simulations. We find that dual-wavelength phase unwrapping is a fast and robust method for removing 2π discontinuities
compared to software algorithm-based methods. In the experiment, two lasers of the different wavelengths 632.8 nm and
671 nm are used to obtain a larger beat wavelength. The object is a phase grating. In dual-wavelength phase unwrapping,
two individual phase images are obtained by using each wavelength, respectively, and the phase image for beat
wavelength is obtained by subtracting one single wavelength phase image from the other and then adding 2π whenever
the resultant value is less than zero. In the final synthetic image, 3D profile of the phase grating is obtained after
removing, the discontinuities by reducing the noise of the beat wavelength phase image. The experiment results
demonstrate the effectiveness of the dual-wavelength phase unwrapping in digital holography.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819228 (2011) https://doi.org/10.1117/12.900567
As we all known that laser-phased-array system can provide an excellent means for achieving random beam steering. In
this paper the crystal of the Lithium Niobate (LiNbO3) will be used as the phase shifter to change the phase. According
to the parameter of LiNbO3 the relationship is presented between the control voltage that loaded on LiNbO3 and phase
modulation. Then, on the basis of the far field coherent combination, the relationship between the control voltage and the
steering angle of the laser beam will be obtained. The numerical results are presented and have verified the theoretical
analysis.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819229 (2011) https://doi.org/10.1117/12.900568
An integrated receiver channel for a pulsed time-of-flight (TOF) laser rangefinder has been designed. Pulsed TOF laser
range finding devices using a laser diode transmitter can achieve millimeter-level distance measurement accuracy in a
measurement range of several tens of meters to non-cooperative targets. The amplifier exploits the regulated cascade
(RGC) configuration as the input-stage, thus achieving as large effective input trans-conductance as that of Si Bipolar or
GaAs MESFET. The RGC input configuration isolates the input parasitic capacitance including photodiode capacitance
from the bandwidth determination better than common-gate TIA. To enlarge the bandwidth, inductive peaking
technology has been adopted. An active inductor (MOS-L) is used instead of spiral inductor in CMOS process. An R-2R
resistor ladder is inserting between per-amplifier and post-amplifier as the variable attenuator for digital gain control
purpose. The gain-bandwidth of a basic differential pair with resistive load is not large enough for broad band operation.
A circuit solution to improve both gain and bandwidth of an amplifying stage is proposed. Traditional and modified
Cherry-Hooper amplifiers are discussed and the cascading of several stages to constitute the post-amplifier is designed.
The fully integrated one-chip solution is designed with Cadence IC design platform. The simulation result shows the
bandwidth of the trans-impedance amplifier is 215MHz with the presence of a 2pF input capacitor and 5pF load
capacitor. And the maximum trans-impedance gain is 136dB. The walk error is less than 1ns in 1:1000 dynamic range.
The responsive time is less than 2.2ns.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81922A (2011) https://doi.org/10.1117/12.900569
We demonstrate and analyze a novel self-mixing laser particle sizing instrument using a He-Ne laser centered at around
632.8 nm and output power is 35 mW. A single mode fiber is used to deliver the incident light to the sample cell and the
fiber probe is worked as an optode. The scattered light is collected by the same fiber and re-injected into the laser.
Experimental investigations are presented for particle sizing using polystyrene particles in water from 100 to 400 nm in
diameter. Diameter of the scattering particle can be obtained by analyzing the optical power spectrum which is related to
the autocorrelation of the measured scattering intensity. The result has a good agreement with theory. As a significant
improvement, we gather the back-scattering light using a fiber optic probe accomplishes a task that is almost impossible
using conventional optics because the multiple scattering in a concentrated opaque suspension. Fiber optics also has the
advantages of being less prone to damage, less expensive and allowing for remote access in transmitting and collecting
light.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81922B (2011) https://doi.org/10.1117/12.900573
As a highly accurate measurement method, Electro-optical detection technique played a key role in many fields.
Weak signal detection has been restricted the Electro-optical detecting equipment monitoring ability. The studies of how
to improve the photoelectric device for weak signal detection and extraction ability, photoelectric devices work level and
strengthen monitoring ability have the great significance.
According to the characteristics of APD photoelectric diode, the laser signal detection circuit has been designed so
that the weak laser signal detection can be realized. The principle of APD photoelectric diode, the noise coefficient and
working conditions have been introduced. by using PWM devices, the APD high-voltage bias circuits can be designed
which has wide range output voltage and continuous adjustable characteristics. The APD amplifier circuit also can be
designed; it mainly introduced three aspects when take consideration on amplifier circuit design, including the bandwidth,
magnification and input impedance. Through the analysis of noise characteristics and laser pulse signal characteristics,
detection circuit noise can be curbed and SNR can be improved, they all contribute to building up a higher sensitivity of
laser signal detection circuit. Detection circuit is applied to laser range finder, laser monitoring and so many various
applications.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81922C (2011) https://doi.org/10.1117/12.900574
The inscription method of FBGs on large-mode-area double-clad fibers (LMA-DCFs) with phase mask technique was
described. A pair of LMA FBGs was prepared and the center wavelengths of them were both around 1076nm with 3 dB
bandwidths of about 0.5nm. The reflectivities of them are 99% and 10% in the fundamental mode, respectively. In order
to be protected and to withstand high-power laser, the FBGs were metally packaged, and then applied to an Yb3+-doped
LMA-DCF laser as the laser cavity. An output power of 314 W centered at 1075.71 nm with a slope efficiency of 60%
was achieved.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81922D (2011) https://doi.org/10.1117/12.900578
A measured range image of imaging laser radar (ladar) is usually disturbed by dropouts and outliers. For the difficulty of
obtaining measured data and controlling noise level of dropouts and outliers, a new simulation method for range image
with noise is proposed. Based on the noise formation mechanism of ladar range image, an accurate ladar range imaging
model is formulated, including three major influencing factors: speckle, atmospheric turbulence and receiver noise. The
noisy range images under different scenarios are obtained using MATLABTM. Analysis on simulation results reveals
that: (1) Despite of detection strategy, the speckle, the atmospheric turbulence and the receiver noise are major factors
which cause dropouts and outliers. (2) The receiver noise itself has limited effect on outliers. However, if other factors
(speckle, atmospheric turbulence, etc.) also exist, the effect will be sharply enhanced. (3) Both dropouts and outliers exist
in background and target regions.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81922E (2011) https://doi.org/10.1117/12.900593
The lock-in effect can reduce the performance of ring laser gyros. The lock-in effect is a result of backscattering.
Self-consistent equations for ring laser gyro show that the intensity of the opposite beams has AC modulation at the
frequency of beat frequency signal because of the backscattering. The amplitude and phase of the AC modulations have
important information about the backscattering. Comparing to the DC component in intensity signal, The AC
components are much smaller, it is not suitable to measure the AC components directly using analog to digital
conversion. A novel synchronous demodulation method is proposed which taking advantage of the heterodyne read-out
signals in quadrature. The coupling modulation under different rotation rate is measured, experiments of this system
show that this system works well and we can draw beneficial conclusion from the experiments.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81922F (2011) https://doi.org/10.1117/12.900594
Passive coherent beam combining, which uses optical feedback from the fibers to force all to lock in phase, seems to be a
promising way for high power output. Fused-taper fiber laser array is one of the passive methods, in which phase locking
is realized by mutual energy coupling, without any active phase control. In this paper, we use a dynamical model to
express phase-locking evolution of the fused-taper fiber laser array theoretically. In the numerical analysis of 3- and 7-
fused-taper fiber arrays, we start the simulations beginning with each laser in an off-state, that is, the initial electric fields
are chosen at random of order 0.1 and the phases are uniformly distributed. The results show that the array can achieve a
relative in-phase state. The coupling degree varies with the distance between the two neighbor fibers. The simulations
also show that the fiber grating reflectivity, the pumping parameters and the coupling length have significant effect on
the stability of the coherent combing.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81922G (2011) https://doi.org/10.1117/12.900605
We present research on high-order Gaussian laser beam cleanup by using adaptive optics (AO)
technique. A 64-element adaptive optics beam cleanup simulation system based on Stochastic
Parallel-Gradient-Descent (SPGD) Algorithm was set up. The far-filed energy centrality of TEM10 mode was
advanced and the evaluation function increased more than a factor of 4.6 when the system evolves from
open-loop into close-loop state. The experiments results indicate the feasibility of Adaptive Optics in mode
transform system.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81922H (2011) https://doi.org/10.1117/12.900673
With the development of electronic device widely used in space and radiation environment, internationally,
they are paying more attention to the research of electronic components resist radiation properties. In order to
improve properties of anti-radiation semiconductor lasers, satisfy variable needs in space applications, this
paper introduces the space radiation environment, and its influence on the semiconductor lasers, analysis
generating mechanism which is including total dose effect of radiation, SEU(Single Event Upset) and
discomposition and so on. And through adopt to the way of Super EBD(Electronic Brakeforce Distribution),
coating Y2O3-ZrO2 film on the semiconductor lasers cavity surface to prove the ability of semiconductor lasers
space resist radiation, use γray irradiation, analysis important indicator of laser like output power of coating
film before and after, current power curve and so on.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81922I (2011) https://doi.org/10.1117/12.900677
In order to study the influence of the time-varying turbulence to facular orientation precision when the facula is moving
during the pointing and tracking process, a random phase screen is generated using modified inverse fourier transform to
simulate atmospheric turbulence. And then the orientation deviation of the facular barycenter, the relation between the
deviation and the facular position in the detector and the orientation precision of the facula is analyzed under different
atmospheric turbulence intensity. The results indicate that at the presence of time-varying atmospheric turbulence, there
is a deviation between actual translational amount of the facular barycenter and that of the barycenter detected by the
charge-coupled device and it relates with the atmospheric turbulence intensity. And the dynamic facular orientation
precision is found that it relates to the atmospheric turbulence intensity and the facular position in the detector.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81922J (2011) https://doi.org/10.1117/12.900680
The omni-directional laser warning equipment based on infrared
fish-eye lens and short-wave infrared FPA has been
used to protect large-scale targets, which can detect the threat laser scattered by the attacked targets or the objects surrounding
them, and image the laser spot on FPA, then fix the position of spot. The application offsets the disadvantage of
direct interception warner which need disposed largely. Before study of imaging mechanism about the scattered laser
spot, the definition of geometry relationship is needed firstly. In this paper we developed a 3D geometry model by analyzing
the position relationships in typical battlefield environment among the enemy's threat laser source, the laser spot
radiated on one flat surface and our omni-directional laser warning fish-eye lens. The model including R, α, β, d, θ, φ, ψ, δ etc. 8 parameters and 4 coordinate systems was suitable for any general situations. After achievement of the model
foundation, we obtained analytic expression of the laser spot contour on flat surface, then attained analytic expression of
spot contour on image surface by calculating the object space half-field angle and the azimuth angle relative to fish-eye
lens of an arbitrary point at the spot edge on flat surface. The attainment of the expression makes possible that we can
analyze the spot energy distributions on image surface and the imaging characteristic of the scattered laser spot via
fish-eye lens, then can compute the transmission direction of the threat laser. The foundation of the model in this paper
has an importantly basic and guiding meaning to the latter research on this aspect.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81922K (2011) https://doi.org/10.1117/12.900685
The Generalized Lorenz-Mie theory(GLMT), which describes the interaction between spherical particles and laser pulses,
is firstly introduced in this paper. Then scattering properties of ultrashort laser pulses by air bubbles in the sea water are
studied, including the scattering efficiency factor, extinction efficiency factor, phase function and degree of polarization,
and influences of the bubble size, pulse duration and scattering angle on pulse scattering properties are discussed. Finally,
pulse scattering properties of bubbles are compared with those of suspended particles in the sea water. The results show
that laser pulses have the smoothing effect, which strengthens with decrease of the pulse duration, but have no influences
on the critical angle scattering and Brewster angle scattering. So they could be measured to distinguish between air
bubbles and suspended particles and thus to detect air bubbles. This will have certain significances on pulsed laser
detection for wake bubbles. The results also show that small bubbles could enhance the backscattering of the sea water,
which is advantageous for pulsed laser detection for wake bubbles.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81922L (2011) https://doi.org/10.1117/12.900708
A key problem for the digital holography is to improve the resolution of digital holographic system. We present a system
for long-range digital holographic imaging with improved resolution using synthetic aperture method. Imaging system is
formed by three sub-apertures, and each sub-aperture receiver contains independently telescope lenses and a CCD
device. Through every sub-aperture system, a hologram is obtained. Subsequently, we numerically reconstruct the
intensity image and get a synthetic image with the resolution improved. The theoretical analysis and simulated
experiment show that the method is reasonable and efficient.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81922M (2011) https://doi.org/10.1117/12.900722
Q-switched Short pulse laser has been widely applied in many fields, such as optical ranging, remote sensing,
communications, nonlinear optics and spectroscopy etc. Q-switched Nd3+: YAG laser, with its high thermal conductivity
and resistance to damage threshold, longer energy levels were generally used especially. Second harmonics generation
was usually obtained through optical nonlinear effects in crystal. To the frequency doubling technology, poor conversion
efficiency and multi-output frequency are the main problems. Researchers focus more on phase and group velocity
matching induced by nonlinear effects, but pays less attention on theoretical modeling and numerical calculation of
factors affecting frequency doubling of pulsed laser. In this article, nonlinear effects of double frequency crystals in
Q-switched Nd3+: YAG laser was first analyzed in theory, then we deduced the relation expressions between factors
affecting the efficiency of frequency doubling( thickness of frequency doubling crystal, cross section area of incident
beam, power of the fundamental field, phase matching of incidence light)and double frequency efficiency. Secondly,
taken KTP Crystal for example; numerical results and theirs' corresponding curves on these relation expressions was
calculated and drawn with MATLAB software. These findings can be used for processing the specific requests of
frequency doubling crystal. Finally, Theory modeling and numerical calculation were tested in experiment. The
experiment results are in good agreement with those obtained in theory.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81922N (2011) https://doi.org/10.1117/12.900727
Laser Doppler velocimetry has the ability to measure speed and surface vibrations non-intrusively with high precision. In
this study the Doppler spectrum shift and spectrum broadening of echo signals by moving targets are investigated. The
interaction between moving object and the laser beam of laser Doppler velocimetry have been described by varying
rotating velocity, the angular velocity, distance and incident facula. By using different scattering surfaces, such as
Polytetrafluoroethylene (PTFE) and sandpaper with different grain sizes, the characteristics of echo signals' Doppler
spectra have been studied experimentally in detail. The results show that Doppler spectrum distribution is changed with
different scattering surfaces. Meanwhile, in order to get a high measuring accuracy, the moving object's scattering
characteristics must be considered carefully.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81922O (2011) https://doi.org/10.1117/12.900734
In the paper, we reported a single-frequency(SF), single-mode(SM), linear-polarized ytterbium-doped all-fiber master
oscillator power amplifier (MOPA) system consisting of two stage amplifier which could be used in coherent detection.
With a pump power of 17.5W at 976nm, the system emitted up to 12.7 W of single-frequency radiation at a wavelength
of 1064 nm with the polarization-extinction ratio (PER) more than 35dB and signal-to-noise ratio (SNR) more than 40dB.
The final-stage amplifier operated with a high conversion efficiency of 73% and the gain of the whole amplifier achieved
31 dB, it has nearly diffraction-limited beam quality.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81922P (2011) https://doi.org/10.1117/12.900736
Narrow linewidth fiber lasers are intensively studied during these years, for their wide use in coherent
optical communication, optical fiber sensing, high-precision spectroscopy and many other industrial and military
applications. A usual technique to suppress linewidth is narrow band filtering in the resonating structure of the laser.
However, it is hard in fabrication for a tradition optical filter to achieve an ultra narrow pass band such as
kilo-Hertz. In this paper, the parallel feedback structure is proposed and experimentally studied. A fiber laser with
ultra narrow linewidth (15Hz detected) is achieved in laboratory, basing on the parallel feedback mechanism in a
fiber ring cavity. In multimode fiber, each transverse mode has a different propagation constant. Equivalently, when
a light beam propagates form single mode fiber to multimode fiber, it will split into a few parallel light paths with
different propagation constants. The parallel feedback structure of a fiber ring laser is carried out by introducing
one or more pieces of multi-mode fiber into its resonant cavity. Lasing light in the cavity must fit the restrictions of
all light paths, thus linewidth of the laser output is suppressed. Ultra narrow linewidth can be achieved by carefully
adjusting the amount and length of multi-mode fiber pieces. The narrowest linewidth achieved in laboratory is
15Hz detected by a delayed self-heterodyne interferometer with a 100km fiber delay line. In this work, we focus on
pressuring linewidth, and mechanism of selecting and stabilizing mode isn't employed. Therefore, the narrow
linewidth fiber laser isn't single-longitudinal-mode (SLM). A similar ring laser structure with bidirectional output
is also experimental implemented, achieving a bandwidth of the same order. The bidirectional ring laser is the basic
component of a laser gyroscope, and its linewidth is one key limiting factor of the gyroscope accuracy. This narrow
linewidth bidirectional ring laser is a good candidate for accurate fiber laser gyroscope. Theory analysis and
experiment shows the fiber ring laser based on parallel feedback structure is robust against environmental
disturbance, achieving high stability and ultra narrow linewidth. The parallel feedback mechanism in optical
circuits can also used in other applications demanding narrow linewidth.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81922Q (2011) https://doi.org/10.1117/12.900742
In this paper, both numerical simulation employing finite element method (FEM) and experimental work by using
laser ultrasound technique was done to investigate the wedge wave modes in wedges with different apex angles. We
focused not only on the wedge waves propagating along the wedge tip, but also the dispersion characteristics of the wave
modes. Firstly, finite-element method was used to simulate the laser induced wedge waves and different orders of wedge
wave modes could be clearly observed for different apex-angle wedges with non-dispersion. Then pulsed laser excitation
and optical deflection beam method for detection was built to investigate the wedge waves experimentally. The wedge
waves at different positions were recorded by scanning the excitation laser source along the wedge tip and the
dispersions and phase velocities of the wedge waves were obtained by using 2D Fourier transformation method. The
numbers of wedge wave modes were observed on wedges with different apex angles is in good agreement with
Lagasse's empirical formula and our numerical simulation.
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Huanqin Wang, Ying Wang, Jun Xu, Deyong He, Tianpeng Zhao, Hai Ming, Deyi Kong
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81922R (2011) https://doi.org/10.1117/12.900747
A LED-array-based range imaging sensor using Time-of-Flight (TOF) distance measurement was developed to capture
the depth information of three-dimensional (3-D) object. By time-division electronic scanning of the LED heterodyne
phase-shift TOF range finders in array, the range images were fast obtained without any mechanical moving parts. The
design of LED-array-based range imaging sensor was adequately described and a range imaging theoretical model based
on photoelectric signal processing was built, which showed there was mutual restriction relationship among the
measurement time of a depth pixel, the bandwidth of receiver and the sensor's signal-to-noise ratio (SNR). In order to
improve the key parameters of sensor such as range resolution and measurement speed simultaneously, some optimized
designs needed to be done for the proposed range imaging sensor, including choosing proper parameters for the filters in
receiver, adopting special structure feedback automatic gain control (AGC) circuit with short response time, etc. The
final experiment results showed the sensor after optimization could acquire the range images at a rate of 10 frames per
second with a range resolution as high as ±2mm in the range of 50-1200mm. The essential advantages of the proposed
range imaging sensor were construction with simple structure, high range resolution, short measurement time and low
cost, which was sufficient for many robotic and industrial automation applications.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81922S (2011) https://doi.org/10.1117/12.900755
Narrow-linewidth high-power fiber pulsed sources have many applications, such as laser remote sensing and
spectroscopy. In this article, an all fiber 1064nm single-frequency pulsed laser in Master Oscillator Power Amplifier
(MOPA) configuration and the corresponding experimental results are presented. The laser consists of four
Polarization-Maintaining (PM) fiber amplification stages. In the final stage, 1.8m long large mode area (LMA)
double-clad gain fiber with core diameter of 25μm and numerical aperture (NA) of 0.06 is utilized. In the system,
considering the low power of the seed laser, a continuous-wave (cw) seed laser is externally modulated by an
acousto-optic modulator (AOM). The modulated pulse repetition frequency (PRF) of the first and the second
amplification stage are chosen to be 10KHz to minimize the Amplified-Spontaneous-Emission (ASE). Then another
AOM is inserted to change the PRF from 10KHz to 100Hz, which also eliminates build-up of optical power emitted
within the same bandwidth of the ASE filter. Besides, in order to prevent the pulse steepening in the amplification stage,
the modulated pulse in the first AOM is pre-shaped and last pulsed shape with almost flat top are demonstrated. The
pulse energy is increased by more than 80% through that special pulse shaped method. In the end, pulse energy of 100μJ
with 500ns pulse duration and 100Hz repetition rate is obtained. Near diffraction limited beam quality (M2 ~ 1.1) is also
proved by coiling the fiber at a diameter of 10-cm.
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Kai-hua Sun, Ling Yuan, Zhong-hua Shen, Xiao-wu Ni
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81922T (2011) https://doi.org/10.1117/12.900756
In this paper, the propagation characteristics of surface acoustic wave (SAW) and longitudinal wave in the iron-based
alumina functionally graded materials (FGMs) were studied by using laser based ultrasonic technology, and then the
ultrasound signals were analyzed to evaluate the properties of FGM. SAW and longitudinal wave were excited on FGM by
using Nd:YAG pulsed laser and then detected by Polyvinylidene Fluoride (PVDF) transducer and laser interferometer,
respectively. By analyzing the dispersion of SAW in the FGM the surface properties of materials were evaluated, and the
internal nature and layered structures of FGM were determined by analyzing longitudinal wave and echo signals. The
experimental results validate the correlation properties of FGM and demonstrate the feasibility and validity of the method
by using SAW and longitudinal wave.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81922U (2011) https://doi.org/10.1117/12.900763
A 3D laser scanning system for rock surface measurement was developed based on structured light measuring technique.
The structure of the system was designed. A fast calibration method for the 3D laser scanning system was presented in
detail. After the system was calibrated, the measuring precision was verified in the depth direction. Experimental results
proved that the measuring precision of the system is better than 0.02mm. And the system can achieve high performance
during practical application.
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Ziming Zhao, Xiangyang Hao, Songlin Liu, Song Zhao
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81922V (2011) https://doi.org/10.1117/12.900779
In the process of hole-repairing in point cloud, it's difficult to repair by the indeterminate boundary of
fragmentary area in the edge of point cloud. In view of this condition, the article advances a method of Fragmentary area
repairing on the edge of point cloud based on edge extracting of image and LS-SVM. After the registration of point cloud
and corresponding image, the sub-pixel edge can be extracted from the image. Then project the training points and
sub-pixel edge to the characteristic plane that has being constructed to confirm the bound and position for
re-sampling. At last get the equation of fragmentary area to accomplish the repairing by Least-Squares Support Vector
Machines. The experimental results demonstrate that the method guarantees accurate fine repairing.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81922W (2011) https://doi.org/10.1117/12.900780
A key application of laser range finder (LRF) is measurement of range to a target. Many
modern LRFs are capable of transmitting laser pulses that are nanoseconds in duration. These
pulses provide excellent range precision. However, randomness in the detected laser signals places
limits on the precision.
The first goal of this paper is to quantify the range precision limits of LRF. The randomness
in the time between photon arrivals, which is called shot noise, is discussed. System-dependent
noise sources such as dark current and detector gain variation are considered. The effect of
scene-dependent parameters including background light. Finally, a noise mitigation strategy, gain
equalization is described and tested on simulated.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81922X (2011) https://doi.org/10.1117/12.900784
High-power diode laser system is still belonging to the novel laser system currently. To realize the output of fiber
coupled high power diode laser will greatly enhance the applications of diode laser. In this article, we simulated beam
shaping and fiber coupling of diode laser with optical design software ZEMAXR, and discussed the problems would be
attended in the process of fiber coupling. Experiments on the beam shaping and fiber coupling were studied. Shape the
diode laser beam, homogenize fast and slow axis beam quality, and then realize high power diode laser output through
polarization coupling and wavelength coupling. Finally through the self-developed fiber coupling device, we achieved a
multi-wavelength high-power fiber-coupled diode laser output, the fiber core diameter 600um, NA 0.22. Before fiber
coupling the power of the diode laser was 773W, after fiber coupling, the output power was 664W, and the efficiency of
the fiber coupling is up to 85.9%.The fluctuation of the power is less than 1%.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81922Y (2011) https://doi.org/10.1117/12.900791
The Gd2O3 hollow microspheres have been successfully fabricated via carbonaceous polysaccharide microspheres
as templates and urea as a precipitating agent, which involved the deposition of an inorganic coating on the surface of
carbon microsphere, followed by heat treated 800°C for 4h. The obtained high uniform Gd2O3 microspheres with a
spherical shape and hollow structure are uniform in size and distribution. The possible mechanism of evolution from
glucose to carbonaceous polysaccharide microspheres and the chemical reaction of each step to form the final hollow
spheres are proposed. The rare earth ion Ln3+ doped Gd2O3 (Ln = Er, Yb and Tm) hollow microspheres show bright
up-conversion luminescence with different colors coming from different activator ions under ultraviolet or 980 nm light
excitation, which may open new possibilities to synthesize other hollow spherical materials and extend their applications.
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Ting-ting Zhang, Yu-bin Wei, Chang Wang, Tong-yu Liu
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81922Z (2011) https://doi.org/10.1117/12.900794
The online monitoring of the Coal Mine inflammable and explosive gases based on optic fiber sensing technologies, is
the main research of spontaneous combustion forecasting system of coal goaf area. In use of the LabView's virtual
instrument development capability, CO concentration monitoring virtual system has been established based on the
tunable diode laser absorption spectroscopy(TDLAS) technology. According to comparison of the results of the virtual
simulation system and the actual monitoring system, indicate that the virtual system can reflect the impact of second
harmonic by dynamic parameters such as concentration, temperature and pressure truly and accurately, provide
theoretical guidance and reference for the overall design of the gas monitoring system.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819230 (2011) https://doi.org/10.1117/12.900795
In the present letter, the transparent oxyfluoride glass ceramics containing Ho3+-Tm3+-Yb3+:NaYF4 were
successfully prepared by melt-quenching at 1400°C and subsequent heating at 650-680°C for 1~2 hours . X-ray
diffraction (XRD) with Cu Kα radiation (λ=0.154nm) investigation revealed that NaYF4
nano-crystals in the glass
ceramics was fabricated. Their sizes were determined by Sherrer's equation. The emission spectra red green and blue
up-conversion (UC) under 980nm laser diode (LD) pumping and absorption spectra were measured. Luminescence
measurements confirmed the partition of RE ions in nano-crystals NaYF4. The blue red and green UC radiations
correspond to the transitions 1G4-3H6, 1G4-3H4 of Tm3+, 5F4,
5S2-5I8, 5F5-5I8, of Ho3+ ions, respectively. This is
similar to that in Tm3+-Yb3+ and/or Ho3+-Yb3+ co-doped glass ceramics. To obtain upconversion fluorescence
mechanisms, upconversion fluorescence intensity versus LD pump power were analyzed in view of energy levels of rare
earth. Up-conversion mechanisms were discussed and the ratio between red, green and blue UC emission bands was
found to be varied as a function of temperature of heat treatment and pump power. This result could be mainly attributed
to the cross-relaxation between Ho3+ ions. The excellent optical properties and its convenient, low-cost synthesis of the
present glass ceramic imply that it is an excellent substitution material for the unobtainable bulk NaYF4 crystal and may
have potentially applications in tunable visible laser or many other fields.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819231 (2011) https://doi.org/10.1117/12.900800
A method for measurement of the absolute phase by using femtosecond laser spectral interference technique has been
reported. Theoretical simulation indicates that the interference fringes of double femtosecond laser pulses are
significantly different when phase difference between the double femtosecond laser pulses is different. An experimental
apparatus based on a Michelson interferometer devices is built, in which one femtosecond laser pulse is split into two
pulses in half by a beam splitter (BS), each pulse is reflected by mirrors and the two pulses are then reunited. The double
femtosecond laser pulses interfere with each other and are focused on a spectrometer to record the spectral interference
fringes. By applying Fourier transformation to the recorded spectral interference signal, we retrieve the absolute phase
between the double femtosecond laser pulses. Theory analysis and experiment results show that this method is
reasonable and efficient, which present a new application of femtosecond laser interference. We believe that the method
reported in this paper provides a useful approach for measuring the absolute phase which should have applications in
determining thickness and measuring refractive index of optical samples.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819232 (2011) https://doi.org/10.1117/12.900804
Laser fuze has been widely used in a variety of large-caliber ammunitions, such as missile, aerial bomb and rocket bomb,
due to its typical advantages of proactivity in target detection, sharp directivity of probe field and strong antielectromagnetic
interference ability. Recently a new kind of small laser fuze adapted to small-caliber ammunitions is
being actively developed. Designed the mathematic model of the laser echo waveform based on Gauss beam and
deduced time domain of echo impulse power with varied sharps of target (such as plane target, circle target and mutant
target). Echo impulse waveform of laser fuse with the noise interference, such as sunlight and raindrop, also has been
studied based on the modeling. The test experiments show that the system can detect weak laser echoed wave,
distinguish target and interferences signal by amplifying, modulating and processing the echoed waveform, and detect
vertical test board (gray iron) at 5m far away with no more than 90mA current. The test results in High overload
conditions indicates that the prototyping can work normally and steadily in the whole trajectory.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819233 (2011) https://doi.org/10.1117/12.900810
A conductively cooled, laser diode (LD) end pumped, injection-seeded single frequency Nd:YAG laser is designed and
implemented. A compact standing wave resonator with dual-end-pumping arrangement is constructed, and two
fiber-coupled LDs with maximum output power of 150 W independently are used as the pump source. A composite
Nd:YAG rod is utilized as the gain medium with the aim of reducing thermal lens. The optimized ramp-fire technique is
applied to build reliable single longitudinal mode oscillating. The laser is capable of producing a 10 mJ Q-switched pulse
at the pulse repetition rate of 100 Hz and 250 Hz. Due to the thermal effect in YAG rod, although the single frequency is
remained at 1000 Hz, the single pulse energy is decreased to 8.8 mJ. The M2 of the laser beam are no more than 1.3 for
all three operation frequency. At 1000 Hz with the output of 8 mJ, the linewidth of 54.2 MHz and the frequency jitter of
less than 3.5 MHz (rms) over 2 min are detected by heterodyne technique.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819234 (2011) https://doi.org/10.1117/12.900811
Currently, the output laser energy was enlarged mostly by using laser application technology
and different pump styles were used, which made the laser volume large. In this thesis, the output laser
energy was increased by improving the quality of laser crystal and using new style doped laser crystal,
which can increase the capacity usage ratio of solid laser, and the beam quality was improved as well. In
the paper, a new double-doped Nd:Ce:YAG laser crystal pumped by Xe-lamp and the plane-plane
resonant was used as main oscillator of laser. There were two advantages using the method. Firstly, the
absorption spectrum and emission band spectrum of Ce3+ were analyzed, which can create energy
transition between Ce3+ and Nd3+. The Ce3+ ion in double-doped laser crystal can absorb pump light at
ultraviolet band and create stimulated emission, which located at the absorption band of Nd3+ and made
more Nd3+ ion create energy level transition. The inverted population increased. As result the capacity
usage ratio of pumped energy was increased and the output energy of laser was enlarged. Secondly for the
advantage of the limitation of plane-plane resonant to laser beam was strong, the angle of divergence was
small at far field and the beam quality was good. Finally the pulsed laser energy was compressed to spike
pulse by using passive Q-switched, and the peak power was increased. The experiments were carried out
under the condition of passive Q-switched. When the input voltage was 800V, the laser beam was
obtained at the oscillator stage, whose output energy was 651.5mJ. The pulse width was 20ns. The slope
efficiency was 0.49%. Angle of divergence was better than 1.2 mrad. And peak power was 32.5KW. The
experiment result is accordant with theoretical analyses. This solid laser has important potential
application.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819235 (2011) https://doi.org/10.1117/12.900823
In the process of the registration of multi-view point cloud, it's difficult to extract the feature points at
present. In view of this condition, the article advances a new automatic registration method of multi-view point cloud
based on Image Registration and ICP Algorithm. After the registration of point cloud and corresponding image, the
feather can be extracted from the image that has plenty of textures compared with the point cloud. And it's beneficial to
improve the precision and efficiency for the next registration. The experimental results demonstrate that the new method
guarantees accurate fine registration.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819236 (2011) https://doi.org/10.1117/12.900828
In the intensive, complex and variable electromagnetic signal environment, traditional electronic receiver cannot
fully meet people's requirements. To overcome the "bottleneck" that appears in electronic receiving system and improve
the detection and interception capabilities of receiving system, the scheme that the acousto-optic signal processing is
introduced to coherent optical detection system is proposed. On the basis of traditional coherent receiving technology,
the effect of ups and downs of random noise is reduced by the use of acousto-optic device. And it improves selectivity of
signals and enhances the capacity of suppressing noise. Thus signals of smooth amplitude and the higher signal to noise
ratio (SNR) are provided for the back-end signal processing.
Based on frequency measurement principle of acousto-optic deflector, diffraction efficiency of incident light is
researched, when signals of different frequencies are as the driver of acousto-optic deflector. By the analysis of the
forming principle of ultrasonic grating and the phase mismatching factor, in theory spatial filtering of acousto-optic
deflector is got, which suppresses the impacts of unwanted signals on signal detection, meets the requirements of
instantaneous frequency measurement and enhances separation ability of signals arriving simultaneously. At the same
time, coherent optical detection system based on acousto-optic effect is constructed and experimental tests are carried out.
The experimental result is consistent with theoretical analysis. And it is conductive to detect and process weak signal.
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Jiajian Zhu, Wenbo Du, Xiaolin Dong, Xiaolin Wang, Yanxing Ma, Pu Zhou, Xiaojun Xu
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819237 (2011) https://doi.org/10.1117/12.900840
In this paper, we studied theoretically influence of the polarization-state fluctuation on coherent beam combining
(CBC) of fiber lasers. We investigated far-field intensity distribution of the coherently combined fiber laser beams
when the polarization-state varies with time and computed the visibility of the beam profile. The CBC of fiber
laser arrays with time-varying polarization-state was mathematically modeled and the effect of polarization-state
fluctuation was numerically evaluated. The dependence of visibility on the number of fiber laser was computed.
Numerical results showed that the polarization-state fluctuation has a serious influence of coherent beam
combining of fiber lasers in the case of small number, nevertheless, if the number of laser is larger than 10, the
minimal visibility can be as high as more than 80% in the case of random time-varying polarization-state
fluctuation.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819238 (2011) https://doi.org/10.1117/12.900843
The transient electrical signal generated by ultrafast photoconductive material irradiated by ultrashort pulse laser is
measured by the time-resolved pump-probe system. The usual
pump-probe experimental setup is used to study dynamic
change inside the material by measuring the change of the laser beam reflectivity or transmisivity. In this paper, the
experimental setup is improved to directly measure transient electrical signals generated by photoconductive material.
The improved experimental setup can directly reflect the carrier status inside the photoconductive material compared to
the usual experimental setup, and the response rate of photoconductive material can be studied by measuring the
transient electrical signal. The work process of the experimental measurement is described. Especially the detection
process of the pump-probe is analyzed in detail. The method of determining the zero of delay time of the experimental
system is presented. The measurement results showed that the width of transient electrical signals measured is on the
level of picosecond. Finally, the signal to noise ratio (SNR) of the improved experimental setup has been analyzed.
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Jiangtao Wu, Zhuqing Jiang, Lei Song, Yujia Wang, Shiquan Tao
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819239 (2011) https://doi.org/10.1117/12.900846
In this paper the imaging properties of volume holographic gratings with different illumination sources are investigated.
In the experiments, the recording material is a 2-mm-thick LiNbO3: Fe: Cu crystal in which a volume hologram is
recorded by two recording beams interfering at the wavelength of 532 nm. The grating recorded at wavelength of 532
nm can be Bragg matched at another wavelength of 640 nm by using a different reconstruction angle. The depth
resolution of the volume holographic imaging system at the wavelength 640 nm is obtained experimentally, which is in
accordance with the theoretical value. The volume holographic imaging with a white light is also conducted in the
experiment. The result shows that more lateral information about the object can be obtained according to the Bragg
degeneracy.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81923A (2011) https://doi.org/10.1117/12.900848
Double-pulse laser experimental results of generating approximately 100 ns temporal delay between the pulses with
polarization beam combining by two sets of flashlamp pumped electrooptical Q-switched laser is reported for the first
time. The interval of co-aligned double-pulse laser can be turned freely from 0 to several hundred nanoseconds. The
maximal relative timing jitter of double-pulse laser is less than 5 ns. The laser beam control is another difficult issue in
developing double pulse laser. Two 1/4 λ waveplates are inserted in the double pulse laser, and the thermal induced
birefringence can be effectively compensated, and the Q-switched laser pulse energy can be increased by 26 percent. The
repetition rate of double-pulse laser is 40 Hz, and output energy per double-pulse is more than 400 mJ.
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Zhiqun Ding, Hongxia Zhao, Xiaohui Fang, Jilong Bao
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81923B (2011) https://doi.org/10.1117/12.900850
A trace detection of C2H2 system using tunable diode laser absorption spectroscopy (TDLAS) technique is described,
which is suitable for monitoring incipient faults in power transformer. In this system, near infrared distribute feedback
laser diode (DFB LD) is used as light source, a 0.5m short optical path cell is used as absorbing cell , two InGaAs PIN
photo diodes are used as detector. Applying TDLAS technique and Wavelength modulation spectroscopy (WMS)
technique, and combining with ARM9S3C2140 processor controlling, the system has been implemented compact and
flexible. The concentration monitoring based on TDLAS method is obtained in situ and in real time, and the detected
precision is below ppm degree, which can meet the needs for power transformer incipient faults.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81923C (2011) https://doi.org/10.1117/12.900855
An efficient single-pass pumped extracavity singly-resonant optical parametric oscillator at 1.57μm eye-safe range using
a non-critically phase-matched KTP crystal is reported. The pump source is a diode pumped Gaussian unstable resonator
Nd:YAG laser with the high beam quality of M2=1.8. The signal energy of 65mJ with the pulse width of 9ns is obtained
under the input pump pulse of 196mJ 12ns. This result provided a clear demonstration that very high pump-to-signal
energy conversion (up to 33.2%) can be achieved from an extracavity OPO even by single-pass pumped method. The
repetition rate range of the all-solid-state OPO device is 30Hz.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81923D (2011) https://doi.org/10.1117/12.900865
Tunable diode laser absorption spectroscopy (TDLAS) based optical fiber methane sensing technology has a
number of advantages compared with conventional electronic methane sensor device, such as high Precision, passive and
intrinsically safe in explosive and hazardous environment as well as immune to electro-magnetic interference. In order to
accurately measure the oxidation rate of coal mine ventilation air methane oxidizer system, and Meet requirements for
accurate measurements to the oxidizer exhaust emissions, A Fiber optic methane monitor based on Distributed feedback
tunable diode (DFB) laser of 1.65um central wavelength is demonstrated. We use a reflective chamber of only a 10cm
effective optical path as sensing gas cell. By the data processing of fitting baseline method, we remove the effect of the
baseline tilt of background Spectral. The system achieves 0 to 0.1% measure range and 5.8*10E-6 minimum detection
sensitivity, and meets the requirements of high accuracy, real-time measure to the oxidizer exhaust emissions.
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Hualiang Zhang, Wei Zhou, Junbo Yang, Xiujian Li, Jichun Tan
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81923E (2011) https://doi.org/10.1117/12.900943
The amalgamation of parallel optical logic processors and parallel optical interconnections is essential for the
rapidly development of the parallel optical computing technologies. According to the light field distribution at the
filtering plane and the output plane of the 4-f optical correlator achieved by theory analysis, the 4-f correlator with
suitable filtering grating can implement free space optical Perfect Shuffle interconnection perfectly. The experiment
results of the left Perfect Shuffle and the right Perfect Shuffle indicate that, based on the 4-f correlators with filtering
grating, the parallel optical logic processors and the parallel optical interconnections can be accomplished perfectly by
the same optical structure, which may introduce the amalgamation of the parallel optical logic processor and the parallel
optical interconnection.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81923F (2011) https://doi.org/10.1117/12.900948
In the conventional coherent detection method, almost all the techniques of splitting and combining homologous
light source have been adopted, as a result of which the coaxial adjustment of signal and reference light
becomes quite complex and the energy utilization is rather low. This paper presents a new coherent detection
method with a shared line based on acousto-optic deflection. By the way of analyzing the optical structure and
the principle of frequency measurement, it proposes basic measures and solutions to improving the system's
accuracy and resolution of instantaneous frequency measurement. Best use has been made of the characteristics
of the diffracted spots so as to optimize the optical path structure and to make the effective superposition of 0
level spot and 1 level diffracted spot, thus realizing the tracking and measurement of electromagnetic spectrum
signal. Experiments show that application of the acousto-optic signal processing method in coherent detection
can overcome the contradiction between the frequency resolution and the instantaneous bandwidth of traditional
communication receiver and meet the demands of the communication system to high intercepted probability,
large instantaneous bandwidth, as well as rapid measurement of pulse. In comparison with the conventional
coherent detection method, this method can make the power of light source reduce by 50%, and receiver's
sensitivity much better than -65dBm, and then the intercept probability reached up to 100%. Moreover, the
frequency resolution is better than 100KHz.All this can achieve the seamless measurement of carrier frequency.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81923G (2011) https://doi.org/10.1117/12.900953
The model for simulating full-waveform LiDAR data was developed as a tool to explore the relationship between the
LiDAR's design, performance and the terrain characteristics. It is a part of work with the overall purpose to develop a
trade-off analysis tool for a spaceborne LiDAR system as a payload of a land-vegetation observation space mission. An
end-to-end propagation of a spaceborne LiDAR sensing pulse through vegetation canopies is considered by the model. It
consists of the modules characterizing the laser and the receiver optical system, atmosphere, land surface, optical
filtering and detectors. This tool can be used to evaluate the effect of instrument configurations on the retrieval of land
surface parameters, and to carry out trade-off studies during the instrument design.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81923H (2011) https://doi.org/10.1117/12.900958
As the result of the synthetic aperture radar technique applied to laser band, SAIL (synthetic aperture imaging ladar) can
provide range-Doppler image of targets with much more high-resolution than its counterpart in microwave band.
However, the complicated structure of coherent heterodyne detection and the significant impacts of laser atmospheric
effect, target depolarization, phase error arising from platform vibration on heterodyne detection efficiency degrades its
performance.
In this paper, an APD and semiconductor laser based range-Doppler imaging ladar is presented. The ladar combines the
(inverse) synthetic aperture technique and direct detection and can obtain the high-resolution image at a relative low cost
and complexity. In the meanwhile, owing to the poor coherence of semiconductor laser, the impact of atmospheric effect
on laser pattern can be released to some extent. Firstly, the system diagram is presented and the components are briefly
introduced; Secondly, the operation principle and performance are formulated detailedly; and then the parameters
determination of the chirped AM waveform is analyzed considering the extraction of the range and velocity and the fine
resolution. Finally, the 1-D range and 2-D range-Doppler imaging procedure are numerically simulated based on the
given target model, which shows that the proposed imaging ladar is effective and feasible.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81923I (2011) https://doi.org/10.1117/12.900966
A stable tunable external cavity diode laser (ECDL) which uses an intracavity electro-optic deflector incorporated
into a Littrow-type external cavity as a wavelength tunable element is proposed. The deflector comprises an
antireflection-coated rectangle Lead Lanthanum Zirconate Titanate (PLZT) electro-optic ceramic with a pair of
parallel trapezoidal electrodes on the up and down surfaces, which can simultaneously change the cavity length and
the beam-grating angle to achieve mode-hop-free tuning. The theory for mode-hop-free tuning will be presented in
this paper, and the model calculations predict that the laser can be tuned continuously by as much as 110GHz. This
new approach is simple in structure with no mechanical moving parts and has potential configuration of compact
grating-stabilized ECDL.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81923J (2011) https://doi.org/10.1117/12.900967
Direct Detect Doppler wind lidar retrieves the three dimensional wind by discriminating the frequency shift of the
atmosphere elastic backscatter signal. The wind measurement sensitivity of edge detect technology based on iodine
absorption lines highly depends on the aerosol backscatter ratio indicating the mixing ratio of aerosol to atmosphere
molecule in the measurement volume. This work adopt an extra nitrogen Raman channel in addition to elastic Mie and
Rayleigh scattering so as to retrieve the aerosol backscatter coefficient on site and in real time. The Doppler lidar
transmitter is a single longitudinal mode laser at 532 nm, and the lidar receiver analyzes elastic-scatter spectrum of
central wavelength at 532 nm, nitrogen Raman spectrum of central wavelength at 607 nm. The lidar prototype is
validated by experiment. Results show that this method is capable of measuring aerosol backscatter ratio profile of
low-altitude troposphere at the same time as wind measurement, which can define the wind measurement sensitivity and
improve the accuracy of wind speed retrieval.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81923K (2011) https://doi.org/10.1117/12.900981
In the process of 3D reconstruction of the target scene with the moving vehicle-borne single-line scanner, a method of
monocular visual positioning is used to locate the exact position of the moving scanner. Attitude sensor, camera and the
laser scanner are located on the same platform which is installed on the vehicle. Data can be collected synchronously.
We obtained a top view according to the observation of camera's attitude by IPM. A series of planform are acquired at
different moment. After dealing with these pictures with operations of extraction Speeded Up Robust Features (SURF),
matching characteristic points and RANSAC algorism, we calculated the transformation matrix between two adjacent
vertical views. The position and direction of the scanner at this moment can be calculated. On this basis, depending on
the sensors' synchronization control algorithm, the original point clouds data got by laser scanner can be registered as a
reference to the traveling track of the moving scanner, and then the 3D reconstruction of the target scene is established.
Experiment result shows that this method is easy to operate, time-efficient, low cost, and the accuracy of the method in
reconstructing 3D scene is demonstrated.
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Zi-nan Wang, Cui-yun Wang, Da-liang Wang, Ping Lu, Xiao-qi Yu, Lian-yu Xu, Yi Yang, Yun Jiang, Li-xin Zhu, et al.
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81923L (2011) https://doi.org/10.1117/12.900983
The distributed feedback laser (DFB) is a typical laser diode where the active region of the device is periodically
structured as a diffraction grating. The output of a DFB laser has one single longitudinal mode and a relatively narrow
line-width, usually several megahertz or one order less. However, applications such as coherent optical communication
and accurate fiber sensing demand an even narrower line-width. An effective method for compressing a DFB laser is
demonstrated. The line-width of a DFB laser, 200 KHz detected originally, is suppressed to sub kilohertz by adding an
external parallel feedback cavity. The DFB laser is normatively designed but without the output isolator. The parallel
feedback cavity is constructed by inserting several pieces of multimode fiber into a standard linear single-mode fiber
cavity. In multimode fiber, each transverse mode has a different propagation constant. Equivalently, when a light beam
propagates from single mode fiber to multimode fiber, it will split into a few parallel light paths with different
propagation constants. The external cavity and DFB cavity form a compound resonant cavity for light beams. Lasing
light in the compound cavity must fit the restrictions of all light paths, thus line-width of the final output is suppressed.
When a passive external cavity is used, the line-width is suppressed to 1.25 KHz, detected by a delayed self-heterodyne
interferometer with a 100km fiber delay line. By adding an erbium doped fiber amplifier (EDFA) into the external cavity
for loss compensation, the result is updated to 430 Hz. This line-width suppressing method can be applied for other types
of fiber lasers in a similar way. The parallel feedback mechanism is also suggested for general laser cavity designing to
achieve ultra narrow line-width light source.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81923M (2011) https://doi.org/10.1117/12.900985
A multimode optical fiber device for the transmission of Nd:YAG laser of 7mJ per pulse is designed. The
device is composed with an optical taper, with the front section of 5mm, and a 50m multimode fiber, with a core
diameter of 0.6mm and numerical aperture of 0.22. Applying the beam quality analyzer, energy meter, CCD
camera, rapid responding detector and other measure instruments, the transmission characteristics of the fiber
device under different conditions are experimentally investigated. In the experiment, the propagation efficiency
and it's stability, spot distribution, divergence angle, far-field beam quality, pulse broadening and other
parameters of the fiber device under different conditions are studied. It has been found that the fiber's
propagation efficiency is unequal with different incidence angle, and for normal zero angle of incidence, the
efficiency is bigger than that with oblique incidence. The divergent angle of the beam out of the fiber is varied,
and the angle is larger, when the fiber is being swung. It is definite that the output beam's divergence angle be
always less than that decided by the fiber's numerical aperture. The results of the experiment show that the beam
mode out of the multimode fiber has almost no relationship with the mode of the input laser, and mainly decided
by the fiber's modes. When the fiber of the device is being swung, the mode and intensity distribution of the
output beam of the fiber are in random variation, and the peak-to-peak value of the light spot' intensity
distribution is more than 20%. Otherwise, the fiber's propagation efficiency is invariable with the fiber in
different motion. The results of the pulse broadening caused by the fiber-optic transmission indicate that the
pulse broadening is less than 1ns for the 52m multimode fiber device, and may be ignored for a laser detecting
system with a response time of ns scale. Other output characteristics of the fiber are also studied, such as the far
beam quality in different moving conditions. The beam images out of the fiber device are illustrated in the paper.
The study may be a reference for engineering practice.
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Lirong Ge, Min Shui, Xiao Jin, Zhongguo Li, Yinglin Song
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81923N (2011) https://doi.org/10.1117/12.900989
The nonlinear absorptive and refractive dynamics of semiconductor zinc oxide (ZnO) are investigated using a modified
time-resolved pump-probe system with phase object performed at 532 nm on picosecond timescale. The measurement
method is based on method with a phase object for measurement of optical nonlinearities and standard time-resolved
pump-probe system. The sample's nonlinear optical properties can be determined by measuring the normalized
transmittance with/without an aperture in the far field. The experimental results show that the nonlinear response of ZnO
is a combination of bound-electronic and free-carrier nonlinearities mechanism. With the theory of two-photon induced
free-carrier nonlinearity, we fitted the experimental results and the nonlinear parameters of ZnO, such as two-photon
absorption coefficient β, two-photon induced free-carrier absorption cross sectionσ and life time of the free-carrier τr are
obtained.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81923O (2011) https://doi.org/10.1117/12.901002
To meeting the testing requirements of high-precision optical surfaces, the absolute testing technology was used for the
optical testing process. Three-Position absolute measurements with the advantage of few requested testing and testing
conditions are often easily satisfaction were used to high-precision spherical surface shape testing. However in the error
process of three-position absolute measurements, cat's position error has an important impact on finally measurement
results, so three-position absolute measurement simulation and error analysis is necessary. In this paper, optical design
software ZEMAX were used to built the model of three-position absolute measurement and three-position absolute
sphere testing algorithm was used to get actual surface. Finally, some experiments about how to determine the location
of standard cat's eye position were carried on and the experiment's result shows that defocus is the most important factor
in cat's eye position measurement.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81923P (2011) https://doi.org/10.1117/12.901003
Due to its breakthrough the electro-optical time response limitation for picosecond dynamics of processes, many research
groups around the world operating in different fields from physics and chemistry to biology, medicine and material science,
utilize laser setups capable of providing subpicosecond pulses and femtosecond-level time delay lines. However
the signal amount of Femto-picosecond Dynamics is about at an altitude of 1%, but the fluctuation of femtosecond probe
pulse at its best can only reach about 5%. Real-time correct the probe pulse is the only effective way to realize
subpicosecond time-resolved detection precision of transient absorption spectroscopy. So in this paper, reference pulse
was drawn into the measurement equipment through different methods to dispel the fluctuation of probe pulse. Firstly, in
the case of Subpicosecond time-resolved transient absorption spectroscopy, probe and reference beams have the same
spectral distribution and derived from the same source to measure the variation of transmittance in the excited volume.
Secondly probe pulse is spatially and temporally overlapped to the excitation pulse, reference pulse spatially overlapped
but temporally anticipated in respect to the excitation pulse. Finally reference pulse passes through the sample in a
different position. The detector can be a CCD camera or a double photodiode. The results shown that when reference
pulse passes through the sample in a different position and detected by CCD, the correction results can reach to 1%.
Which meet the femto-picosecond dynamics precise requirement.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81923Q (2011) https://doi.org/10.1117/12.901004
Incoherent Doppler wind lidar measures the wind by detecting the frequency shift of the laser backscattering from
aerosol and atmosphere molecules. The wind measurement sensitivity of edge detection technology like iodine vapor
filter depends on the aerosol load of probe volume. The current Direct detect wind lidar system has to obtain the
measurement sensitivity from the independent measurement or prior atmosphere aerosol data before accurate wind
retrieval. Otherwise, the variation of aerosol mixing ratio would introduce great uncertainty in the wind speed
measurement, which is unacceptable on airborne and space-borne Doppler lidar. This paper proposes a new method to
achieve real-time wind speed calibration by three adjacent frequency laser pulses alternately transmitted. Three laser
pulses are frequency locked to the middle and two wings of the iodine filter absorption line. Because the frequency of
triple pulses is changing rather fast, it can be approximately regarded as a synchronous measurement of both aerosol
mixing ratio and wind speed. By this way, we can not only ensure the wind measure accuracy, but also achieve the
reliable wind field measurement on a mobile platform.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81923R (2011) https://doi.org/10.1117/12.901008
Lidar system often use pulse range method, phase detection (PD) range method and linear frequency modulation
continues wave (LFM/CW) range method. Each method has its limit between range resolution and no fuzzy range. In
this paper, a Lidar system with high range resolution in a long distance is designed by using LFM/CW range method
cooperating with PD range method. A MCU is used to control the system working on LFM/CW range mode and PD
range mode alternately. In which LFM/CW range mode is used to obtain an approximate target range with low
resolution in long distance, and PD range mode is used to obtain a high resolution range value within one resolution of
LFM/CW range mode. Then use the PD mode's range value to amend the range from LFM/CW method, and achieve
high range resolution in long distance. This paper describes the system's principle. The simulation and experiment
results in typical object situation prove the system could achieve high range resolution effectively.
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Zhifang Zhao, Xiaomei Chen, Fengjun Zhang, Jie Chen, Sumei Zhou, Xiaoping Jiang, Desen Liu
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81923S (2011) https://doi.org/10.1117/12.901009
We fabricated a single-layer rotundity PMLA with the photolithography and ion-exchanging technique whose
parameters is developed in experiment. The theory show that the multiple imaging is obtained by both single-layer
PMLA and double-layer PMLA while the comprehensive imaging is obtained only by double-layer PMLA. The imaging
condition of comprehensive imaging for double-layer PMLA is analyzed that the magnification must be equal to 1 in this
paper. The ray trajectory equation of PMLA is accord with rotation-symmetric model, and the paraxial optical properties
of PMLA is obtained by ABCD law. At last, the location parameter of comprehensive imaging is obtained according to
the imaging condition.
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Xiao-lin Dong, Pu Zhou, Xiao-lin Wang, Yan-xing Ma, Wen-bo Du, Jia-jian Zhu, Xiao-jun Xu, Shao-feng Guo
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81923T (2011) https://doi.org/10.1117/12.901017
We have demonstrated a novel approach to obtain high power
narrow-linewidth fiber laser radiation by incoherent
beam combination of three single-mode fiber lasers utilizing a laser combiner. The central wavelength of the fiber laser
is 1080 nm with an optical bandwidth narrower than 0.3 nm. Each fiber laser channel is based on a direct pumped
oscillator. In every laser channel, a 976 nm wavelength, 105 μm fiber pigtailed laser diodes of 9-W maximal power are
employed, and the pump power is directly launched into the
double-clad Yb-doped fiber. The three single-mode fiber
lasers are then incoherently combined by a 4×1 laser combiner. More than 14 W total output power is obtained with a
combining efficiency of 90% above.
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Yunying Wang, Huili Wang, Shengtao Chen, Yi Qi, Huanying Liu
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81923U (2011) https://doi.org/10.1117/12.901019
There are lots of bubbles of different diameters in the sea. Our interest is the bubbles which are of micron order
diameters, because the life time for there bubbles are longest even to several hours. To detect the optical characters of
such small bubbles can be uesd to detecting the targets in the sea. The Mueller matrix can be used to describe the
scattering process of the laser transmitting in the medium which contains all the polarization information in an elastic
scattering process. A system is developed for measuring the Stokes vector of the micro-bubbles in lab. The Stokes vector
can be calculated by I||, I⊥, I+ and IL that separately correspond to the parallel intensity, perpendicular intensity, positive 45° intensity and right circle intensity of scattering light. The Mueller matrix of the micro-bubbles has been calculated by
the Stokes vector measured. The scattering of the bubbles introduced the circle polarization into the light beam
transmitted.
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Ling Yuan, Yi-ping Cui, Zhujun Gu, Zhong-hua Shen, Xiao-wu Ni
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81923V (2011) https://doi.org/10.1117/12.901027
Among complex materials, honeycomb sandwich structure has a lot of advantages. However, it is usually found
poor bonding or even debonding. Some convenient nondestructive methods should be found to measure the defect
efficiently.
Laser-generated ultrasound detection is a new nondestructive method with a bright future. Compared with
traditional methods, the advantages of non-contact and high resolution in spatial and temporal made it applicable not
only in measuring defects with high precision, but also in the characterization of various complex shapes. In this paper,
to detect the debonding of the honeycomb sandwich board, the
laser-generated ultrasound technology was used. By the
use of the finite element method (FEM), a 2D model dealing with laser-generated ultrasound in the honeycomb sandwich
board was presented. Take into account of the debonding problem, by adopting the scanned laser source, the propagation
of Lamb wave and longitudinal wave were studied. The debonding in the honeycomb sandwich board was assessed
though the characteristic of the Lamb wave and longitudinal wave in time domain and frequency domain.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81923W (2011) https://doi.org/10.1117/12.901032
A turbulent simulating device in inner field, which is used to research the process of laser propagation in atmospheric
turbulent, could avoid to be disturbed by many casual factors from the atmosphere disturb. For the sake of eliminating
uncertainty of the atmosphere disturb, a physical simulation turbulent system using phase plates based on Kolmogorov
spectrum is designed to carry out a beam spot scintillation experiment of laser propagation. The physical simulation
turbulent system employs two phase plates with micro-fabricated surfaces with the characteristic of Kolmogorov
spectrum. The formula of simulated atmospheric coherent length of the optical system is given for the motive of
adjusting different turbulent conveniently. With the movement in a cone-shape path optical system, the different
coherence length to simulate atmospheric turbulent can continuously be adjusted in a wide range. In the experiment of
beam spot scintillation, a He-Ne laser of 632.8 nm wavelength with 3.5 mm beam diameter is adopted as the propagation
source, which is expanded to 10mm diameter with the expanded lens. The beam passes through all the optical element of
the whole turbulent simulation system in sequence. Finally the beam spot reaches the CCD for picking spot images and
the detector of laser energy meter for collecting the power of spot scintillation. When the distance between the phase and
field lens is adjusted to a longer simulated coherent length, it is observed that whole spot is fractured due to serious phase
aberration. We measured the power of spot in one rotation period of the phase plate. The normalized power amplitude
distribution histogram and the normalized logarithm power amplitude distribution histogram of the intensity scintillation
data in the experiment are given in the paper.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81923X (2011) https://doi.org/10.1117/12.901036
Inventory checking is one of the most significant parts for grain reserves, and plays a very
important role on the macro-control of food and food security. Simple, fast and accurate method to obtain
internal structure information and further to estimate the volume of the grain storage is needed. Here in our
developed system, a special designed multi-site laser scanning system is used to acquire the range data clouds
of the internal structure of the grain storage. However, due to the seriously uneven distribution of the range
data, this data should firstly be preprocessed by an adaptive re-sampling method to reduce the data
redundancy as well as noise. Then the range data is segmented and useful features, such as plane and cylinder
information, are extracted. With these features a coarse registration between all of these single-site range data
is done, and then an Iterative Closest Point (ICP) algorithm is carried out to achieve fine registration. Taking
advantage of the structure of the grain storage being well defined and the types of them are limited, a fast
automatic registration method based on the priori model is proposed to register the multi-sites range data
more efficiently. Then after the integration of the multi-sites range data, the grain surface is finally
reconstructed by a delaunay based algorithm and the grain volume is estimated by a numerical integration
method. This proposed new method has been applied to two common types of grain storage, and experimental
results shown this method is more effective and accurate, and it can also avoids the cumulative effect of errors
when registering the overlapped area pair-wisely.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81923Y (2011) https://doi.org/10.1117/12.901040
Range-gated laser active imaging technology can apparently advance the imaging and identification performance for
long-range dim target. In the atmospheric conditions, the range-gated imaging system performance is generally affected
by many factors, such as wind, visibility, and so on. These influences are more apparent when the laser path is long. To
study the long-range performance of the range-gated imaging system, we carried out a series of outfield experiments
using an active imaging prototype system designed by ourselves. The laser active imaging prototype system includes a
YAG laser, an intensified CCD (ICCD), several lenses for imaging, time control board, and image collecting system. To
test the prototype system's performance and the influence factors, we chose many long range targets on the hills around
our lab and carried out lots of experiments. To test the visibility influence on the system, we fixed the prototype system
and chose a 3.7km telegraph pole as the target, and carried out imaging experiments in several days in different weathers.
To test the gated performance, we chose four close targets all in one sight about 4.2km far away, and got each target
image separately by adjusting the delay time. We get clear laser image of the beacon tower on the Great Wall in 10.9km
far away, and the farthest target we got was the mountaintop distance of 21km. By analyzing the result, we get more
knowledge about the ranging and imaging performance of the laser active imaging system, and the experiment data is
helpful for system design and application in the future.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81923Z (2011) https://doi.org/10.1117/12.901044
In the process of oil exploration and development, it becomes difficult to identify the lithology of cuttings due
to the small size of cutting particles produced by extensively used Polycrystalline Diamond Compact (PDC)
drill bit. Laser Induced Breakdown Spectroscopy (LIBS) is an appealing technique compared with many
other conventional analysis methods due to its simple set-up, on-line, real time, stand off and multi-element
analytical capabilities. In this paper, a newly developed approach for cuttings identification using
laser-induced breakdown spectroscopy was introduced. Principal component analysis (PCA) and partial least
squares (PLS) were applied to analyze LIBS spectra of three drill cuttings to perform cuttings identification.
With the purpose of reducing workload and improving predictive accuracy, 23 characteristic spectra ranges
were extracted as "fingerprints" from each integrated LIBS spectrum. Leave-one-out cross-validation method
(LOO-CV) was used to evaluate the predictive capability of this approach. All the LIBS spectra were identified
correctly under a lax criterion. The obtained preliminary results demonstrated the potential feasibility of cutting
identification using LIBS in combination with chemometric methods.
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Cuiyun Zhou, Xia Hou, Song-tao Du, Yuan Liu, Wei-biao Chen
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819240 (2011) https://doi.org/10.1117/12.901055
An all-fiber master oscillator power amplifier (MOPA) structured pulsed ytterbium (Yb)-doped fiber amplifier is
reported in this paper. This amplifier utilizes a single seed diode, which is current-driven to generate optical pulses.
The pulses repetition rate is tunable by changing the driven signal repetition rate. The seed pulses are then amplified
in a series of Yb-doped fiber amplifiers (YDFAs). The Yb-doped fiber has a large range of fluorescence spectra near
1μm. The cross section of Yb-doped fiber show that input signals ranging from 1000 nm to more than 1100 nm can
be amplified in this kind of fiber. This provides a large range of wavelength for amplification. The gain
characteristics of Yb-doped fiber amplifier were analyzed. The output pulse shape during the signal amplification
was also studied. In order to prove the ability of Yb-doped fiber's amplification, we can then perform actual
experiments by changing the seed diodes which operating at different wavelength. Here we choose 1030 nm (near
an absorption peak of Yb-doped fiber) and 1064 nm (a common wavelength of laser) as the seed wavelength for
amplification. The results of the experiment show that both these two wavelength operate well in Yb-doped MOPA
structured fiber laser. From the spectrum of the amplified output laser, we can see that the amplified spontaneous
emission (ASE) noise is 40 dB lower than the laser signal peak. When the pulses repetition rate is 50 kHz, the final
Double-clad Yb-doped fiber achieves a peak power of 14.4 kW without invoking deleterious nonlinear effects.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819241 (2011) https://doi.org/10.1117/12.901060
Laser-phased-array system provides an elegant means for achieving the inertial-free, high-resolution, rapid and random
beam steering. In laser-phased-array system, phase controlling is the most important factor that impacts the system
performance. A novel scheme is provided in this paper, the beam steering is accomplished by using crystal fiber array,
the difference length between adjacent fiber is fixed. The phase difference between adjacent fiber decides the direction of
the output beam. When the wavelength of the input fiber laser is tuned, the phase difference between the adjacent
elements has changed. Therefore, the laser beam direction has changed and the beam steering has been accomplished. In
this article, based on the proposed scheme, the steering angle of the laser beam is calculated and analyzed theoretically.
Moreover, the far-field steering beam quality is discussed.
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Hong Zhang, Chun-pin Yang, Wei Li, Chao Yang, Xi Chen, Fan Ji
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819242 (2011) https://doi.org/10.1117/12.901066
This paper presents the phenomenone of two fiber lasers coherent with each other without active control. The laser arrays
will spontaneously self-organize into in-phase supermode once the conditions are met. In the experiment, the method of
fused-biconical is used. It is significant to utilize evanescent-wave interaction to achieve the in-phase supermode. Only
the adjacent neighbor fiber are closed enough, the interfering pattern can be obtained. Of course, in order to obtain the
interference pattern of the laser output, every procedure must be perfect, such as the distance of the fiber cores, the
tapered slope. Otherwise the coherent pattern will not be achieved. In the paper, according to the coupled theory, the ideal
supermode of the two fiber lasers were analyzed. The intensity distribution of the supermode in the near field and far
field were obtained. In the experiment, the phenomen of two fiber lasers coherent with each other was observed.
comparing with the spectra of the lasers before interaction with each other, the modes of the spectra is diffrent with
spectra before combining, and also is not the simply superposition of the fibers which are pumped individually. Some
modes were restrained, some were promoted, then they are coherent with each other.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819243 (2011) https://doi.org/10.1117/12.901073
Laser Induced Breakdown Spectroscopy (LIBS), as an in-situ, real time, multi-element analysis tool, has been used in
many applications. While for oceanic applications, many difficulties arise due to lower ablation efficiency and shorter
emission lifetime of LIBS in water. The complexity of ocean environment makes LIBS performance even worse. To
evaluate the potential using of LIBS for oceanic application, extensive experimental investigations of LIBS have been
carried out with a nickel sample submerged in water under both single pulse and dual-pulse laser ablation. It was found
that, for short duration laser pulse ablation, the continuum emission lifetime was nearly equal to the duration of laser
pulse, with nickel atomic emission hardly appeared. As the laser pulse duration going up to 50 ns, several nickel atomic
lines were turned up on the continuum background. With dual-pulse laser ablation, the intensity of theses nickel atomic
lines were enhanced significantly, which demonstrated that dual-pulse had better LIBS performance. The LIBS signals
of nickel target within the wavelength range of 330nm-390 nm were obtained under dual-pulse laser ablation. And
severe self-absorption phenomenon was observed among those nickel atomic emission lines. The possible reason for
self-absorption has been discussed and was attributed to the relevant transmission energy levels. To verify the effect of
cations in water, LIBS investigation was carried out with the nickel target submerged in Na+, K+ solution or deep-sea
water. It was found that both intensity and signal to background ratio had been improved with the cations in water.
All those obtained results suggested that LIBS had great potential to be used in oceanic application.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819244 (2011) https://doi.org/10.1117/12.901098
We report high pulse energy generation from an Yb-doped fiber laser mode-locked or passively Q-switched by a
graphene saturable absorber. In the case of mode-locked operation, a ring cavity was used. The average output
power is 170 mW and the repetition rate is 1.04 MHz, corresponding to single pulse energy of 163 nJ. To the
best of our knowledge, this is the highest pulse energy reported for fiber lasers mode-locked with graphene
saturable absorber. In the case of passively Q-switched operation, a linear cavity was used. The average output
power is 12 mW and the repetition rate is 257 kHz, corresponding to single pulse energy of 46 nJ with pulse
width of 70 ns. We believe we are among the first to report the stable passively Q-switched operation by
graphene saturable absorber in a Yb-doped fiber laser as well. Graphene-based saturable absorber shows
promising potential to replace SESAM as mode-locker or Q-switcher for pulsed lasers in the near future because
of the good performance, easy fabrication, low cost and wide availability.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819245 (2011) https://doi.org/10.1117/12.901221
We developed a high accuracy thickness measurement system for glass substrates based on the optical design
of the astigmatic method. Reflective optical measurement systems are the most widely used glass thickness measurement
methods in current industrial production practice. The incline of glass in reflective optical measurement system is the
main factor of inaccuracy of thickness data. Compared with reflective optical measurement system, we found our design
could effectively eliminate errors of glass thickness caused by slightly shifts of glass tilt. The astigmatic optical system
includes a laser diode, a cylindrical lens, and a quadrant detector. This method measures the astigmatic focusing error
signal induced form the measured glass placed in the astigmatic optical system. The astigmatic focusing error signal is
converted into the thickness of the glass substrate. The proposed glass thickness measurement system is verified by using
a coordinate measuring machine (CMM). On the validation of our system using tri-ordinate measuring machine, the
accuracy of the proposed system is 0.2 μm, with a standard deviation of 0.7μm within the thickness measuring range of
1.2mm.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819246 (2011) https://doi.org/10.1117/12.901236
The fast steering mirror introduced in this paper using Giant Magnetostrictive Material (GMM) as the offset-generating
component, the FSM was actuated by the elasticity of the GMM, which was controlled by the magnetic field generated
by the current in the coil around the GMM. This fast steering mirror was applied in the tilt correction system for
atmospheric laser beam propagation, and the tilt introduced by the turbulent current was reduced by 90%, the stability
and concentration of the laser facula was enhanced greatly.
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Wen-bin Qin, You-qiang Liu, Yin-hua Cao, Zhi-yong Wang
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819247 (2011) https://doi.org/10.1117/12.901534
As the continual improvement of technology and beam quality, diode laser, with poor beam quality, no longer just apply
to pump solid-state laser. As a kind of implement of laser materials processing, high-power diode laser has been used in
manufacture, as a brand new means of laser processing. Due to the influence of inevitable unstable factors, for example,
the temperature of water-cooler, the current of power supply, etc, the output power of diode laser will be unstable. And
laser output power, as an important parameter, frequently affects the performance of the laser beam and the
experimental results of processing, especially in the laser materials processing. Therefore, researching the real-time
power measurement and control of high power diode laser has great significance, and for diode laser, it would improve
performance of itself. To achieve the purpose of real-time detection, traditional measuring method, placing a power
sensor behind the total-reflection mirror of laser resonant cavity, is mainly applied in the system of gas laser and
solid-state laser. However, Owing to the high integration level of diode laser, traditional measuring method can't be
adopted. A technique for real-time measure output power of high power diode laser is developed to improve quality of
the laser in this paper. A lens placed at an angle of 45° in the system was used to sample output light of laser, and a
piece of ground glass was used to uniform the beam power density, then the photoelectric detector received an optic
signal and converted it into electric signal. This feeble signal was processed by amplification circuit with a filter. Finally,
this detected electric signal was applied to accomplish the closed-loop control of power. The performance of power
measurement and control system was tested with the 300W diode laser, and the measuring inaccuracy achieved was less
than ±1%.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819248 (2011) https://doi.org/10.1117/12.901581
The hydroxyl radical plays a central role in the chemistry of the Earth atmosphere since it determines the
lifetime of many chemical species under both clean and polluted conditions. This paper gave a new method for
measuring tropospheric hydroxyl radical based on cavity ring-down spectroscopy(CRDS) which is a kind of
spectroscopic method and widely applied to measurements of gas species, metal clusters and radicals.
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Zhi-yuan Song, Shao-lan Zhu, Li-jun Dong, Li Feng, Hao-dong He
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819249 (2011) https://doi.org/10.1117/12.901928
The traditional technique of phase laser range finder is mixing high frequency signals with analog circuits and filtering
them to obtain the useful signal with low frequency. But the analog mixing circuits are susceptible to interference and
will bring amplitude attenuation, phase jitter and offset and this way has difficulties in achieving high precision ranging
and fast speed ranging at the same time. The method of this paper is based on under-sampling technique with digital
synchronous detection and referring to Digital down converter technique of digital IF receiver in radar system. This
method not only reduces the complexity of data processing, improves the speed and accuracy of phase detection at the
same time, but also reduces requirements for ADC devices and DSP chips in the ladar system by a lower sampling rate.
At the same time, the structure of electronic system is global simplified compared with traditional analog ladar system
and the anti-jamming is greatly enhanced. So this method has important research value.
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Li-jun Dong, Shao-lan Zhu, Chuan-dong Sun, Cun-xiao Gao, Zhi-yuan Song
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81924A (2011) https://doi.org/10.1117/12.901932
Three-dimensional imaging laser radar (3-D ladar) is widely used in area of modern military, scientific research,
agriculture and industry. Because of its many features such as angle-angle-range capturing, high resolution, anti-jamming
ability and no multipath effect ,but it has to scan for target searching, acquiring and tracking. This paper presents a novel
probability model of target acquiring which provides a theoretical basis for optimizing the scanning mechanism. The
model combines space and time, target moving velocity and ladar scanning velocity together. Then the optimum
scanning mechanism to obtain the maximum probability of acquisition and associated with different targets can be
gained. The result shows that this model provides a method to optimize parameter for designing of the scanner.
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Jia Xu, Jiang Liu, Sida Wu, Quan-Hong Yang, Pu Wang
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81924B (2011) https://doi.org/10.1117/12.902217
We report high energy low-repetition-rate graphene mode-locked
Er-doped fiber laser with a long ring cavity. The stable
227 kHz nanosecond pulse is generated at diode core-pumped power of 44 mW. Increasing the pump power to 110 mW,
we achieved the maximum output power of 15 mW, corresponding to single pulse energy of 66 nJ. The pulse width was
measured to be 16 ns. The spectral central wavelength was 1559.6 nm and 3dB bandwidth of the emission spectrum was
0.76 nm. The time-bandwidth product (TBP) of the pulse was ~1499, indicating that pulses were highly chirped. To
the best of our knowledge, this is the first report for graphene mode-locked Er-doped fiber laser in such low repetition
rate and high pulse energy.
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Shi-tu Luo, Xiang-lin Tan, Meng-chun Pan, Cheng-guang Fan
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81924C (2011) https://doi.org/10.1117/12.902223
Laser-generated ultrasonic non-destructive testing technology is a new cross-technology which utilizes lasers to excite and
detect ultrasound, possesses the characters of complete non-contact, fast response, non-destruction, wide band range, high
precision and low cost, can be used in some situations in which traditional piezoelectric ultrasonic testing is hardly
applicable. In this paper, the fundamentals, application fields and development trend of laser-generated ultrasonic
non-destructive testing technology are summarized. Firstly, the development and research situation of laser-generated
ultrasonic non-destructive testing technology are introduced. Secondly, the laser-generated ultrasound excitation
mechanism and ultrasound detection technology of laser-generated ultrasonic and are made a comprehensive review and
summary. Finally, the main technical difficulties, future resolving direction and development trend of this technology are
briefly analyzed. It is concluded that laser-generated ultrasonic testing technique will be applied more widely in the future,
however, revealing the mechanism of laser-generated ultrasound and improving photoacoustic conversion efficiency and
detection sensitivity are the key for the successful application of the technology, and also a focus of present research in this
technical field.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81924D (2011) https://doi.org/10.1117/12.902305
With the acceleration of globalization and regionalization of the world economy, port is playing an
increasingly important role for that it is an international transportation hub port interface and the support of
the international trade platform. How to effectively reduce labor costs, improve the working environment,
stable productivity, reduce the production cuts caused by human intervention and improve the management of
real-time monitoring of all the major ports has become a common issue faced. In order to achieve the
automatically stacking and reclaiming process of Stacker-Reclaimer in the bulk material yard, the source of its
control is expected to identify the stockpile in the bulk yard, including length, width, height, the starting
address, destination address, as well as Three-dimensional shape of the stockpile, since in the operation
process, stockpile changes the shape dynamically. As a result, the real-time three-dimensional shape and
coordinate of piles should be achieved. Based on the existing Stacker-Reclaimer in Qinhuangdao Port coal,
we study the large field of view real-time three-dimensional laser scanning imaging theory and technology.
The overall system design to achieving the three-dimensional laser scanning image is presented. The working
principle of the three-dimensional laser scanning imaging system is analysised. Moreover, the parameter
designation, the technical parameters and the composition of the whole system are all given. The research of
the thesis is also used for other large-scale three-dimensional modeling of piles and the volume computing. In
a world, the method has wide application prospect.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81924E (2011) https://doi.org/10.1117/12.902421
This paper analyzes the effects of thermal blooming on the Far-Field Irradiance Distribution, based upon the
steady-state thermal blooming model, which is introduced by Wallace. It uses the method of numerical simulation and
gives the relativity between thermal blooming and these parameters, including initial power,the radius and wavelength. The result reveals that a new void dimensional parameter can describe the extent of thermal blooming. When this dimensional parameter decreases, thermal blooming effect becomes more serious. The result can provide theoretic
analysis of thermal blooming effect on the Far-Field. In addition, when the wavelength or the radius changes, the result of Wallace model does not accord with the fact. The contradiction reveals the shortcoming of this model.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81924F (2011) https://doi.org/10.1117/12.902422
This paper describes the contents of a general "four-dimensional" computer code for the transient thermal blooming of multi-pulse laser beam propagation. The solutions of the scalar wave equation in Fresnel approximation and the hydrodynamic equations are obtained by means of the discrete Fourier transform method. Based upon the scalar wave equation and the equations of hydrodynamics, the paper makes a model for collimated multi-pulse laser, simulates the
transient thermal blooming numerically, and gives the laser beams irradiance distribution by changing respectively the
value of the propagation distance, the pulse-repetition rate, the power, and the time. Besides, we simulate the
thermal blooming of cw in order to make a contrast with multi-pulse laser. The results show multi-pulse lasers minimize
thermal-blooming; if the pulse-repetition rate decreases, thermal blooming decrease, and the quality of the beam is better.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81924G (2011) https://doi.org/10.1117/12.902439
The nonlinear error of a homodyne interferometer is presented: the amplitudes, the phase and the offsets. An improved
compensation method is introduced since the conventional Heydeman modal' calculation is very time-consuming. First,
the "zero drift" problem is solved with the polarization phase-shifting technology; second, a fast algorithm based on the
Heydeman method is introduced to calculate the errors; and third, electronic circuit is used to remove the nonlinear
errors timely. The test result shows that the nonlinearity of the homodyne interferometer could be reduced to subnanometer
over the measuring range of 20cm, and the accuracy can be improved more than tenfold by the dynamic
compensation method.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81924H (2011) https://doi.org/10.1117/12.902697
The recovery technology of unmanned aerial vehicle (UAV) is one of the difficulties of UAV development.
This paper presents an automatic UAV recovery guide system, which is based on laser detection technology.
The guide system overcomes the problem that the small-sized UAV is not suitable for accurate-point
recovery. Comparing to traditional recovery system, this system has some advantage, such as high precision,
round-the-clock, flexible and easy testing. Especially, it improved the application level of UAV recovery
system with corresponding orientation guide model and accurate orientation tracking technology. High
requirements are needed for UAV near field distance measurement with this method. This paper provides a
method for UAV close quarters navigation based on laser detection technology. It is a new application for
computer vision and photoelectric technology, with fast safe secret and nil interference. UAV recovery
system can lead the UAV to tackle net safely. According to current UAV technology development, using
laser tracking as terminal guide sensor measure equipment is feasible. The distribution of UAV collision
network callback system put the laser recovery guide system behind the tackle net. When the UAV enter the
callback phase, laser call back system made the UAV slide down follow the direct orbit by way of
searching tracking and orientation. The UAV recovery system setups biaxial automatic turntable, measure
the horizontal angle and pitch angle change, provide the deviation of current flight path and destine flight
path, also provides the distance information between UAV recovery system by the way of laser
measurement. This thesis analyzes the feasibility of this technology, provides the workflow of the UAV
when entering the call back process. This paper also presents the correction method of laser error. The
simulation result shows this distance measure system can lead the UAV call back safely.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81924I (2011) https://doi.org/10.1117/12.902741
Fresnel telescopy (short for Fresnel telescopy full-aperture synthesized imaging ladar) is a new high resolution active
laser imaging technique. This technique is a variant of Fourier telescopy and optical scanning holography, which uses
Fresnel zone plates to scan target. Compare with synthetic aperture imaging ladar(SAIL), Fresnel telescopy avoids
problem of time synchronization and space synchronization, which decreasing technical difficulty. In one-dimensional
(1D) scanning operational mode for moving target, after time-to-space transformation, spatial distribution of sampling
data is non-uniform because of the relative motion between target and scanning beam. However, as we use fast Fourier
transform (FFT) in the following imaging algorithm of matched filtering, distribution of data should be regular and
uniform. We use resampling interpolation to transform the data into two-dimensional (2D) uniform distribution, and
accuracy of resampling interpolation process mainly affects the reconstruction results. Imaging algorithms with different
resampling interpolation algorithms have been analysis and computer simulation are also given. We get good
reconstruction results of the target, which proves that the designed imaging algorithm for Fresnel telescopy imaging
system is effective. This work is found to have substantial practical value and offers significant benefit for high
resolution imaging system of Fresnel telescopy laser imaging ladar.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81924J (2011) https://doi.org/10.1117/12.902755
Airborne laser scanning (ALS) is an active remote sensing technique that can provide 3D information about the scene. Over the last few years, ALS has proved its capability of rapid acquisition of accurate topographic data. With
the advantages of high accuracy, ALS data has become an accepted data source for highly automated acquisition of
digital surface models (DSM) as well as for the generation of digital elevation models (DEM) which have been used in
many applications such as civic planning, military navigation and natural hazard risk assessment. To utilize the 3D data
provided by the ALS systems however, efficient methods for data processing and model construction needs to be developed. In this paper some recent technique on analysis and visualization modelling of ALS data will be presented. After the brief presentation of the ALS system, the computation of ALS data is introduced. The data processing chain for
producing DSM is outlined. A data filtering method is proposed for generating DEM. A 3D visualization modelling study
on ground scene is carried out and the framework of establishing visualization of DSM and DEM using ALS data is brought as well.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81924K (2011) https://doi.org/10.1117/12.903171
Pressure and temperature cross sensing restricted the application of bare fiber FBG , especially when FBG was
used to measure low hydrostatic pressure. Side-hole package is practical to overcome pressure and temperature
cross sensing and enhance FBG pressure sensitivity to measure hydrostatic pressure, but it aroused package
stability problem that the FBG spectrum seemed distortion, which will brought measurement difficulties. Novel
side-hole package was raised, with reasonable structure and mechanism, to improve the package stability and
eliminate FBG distortion. The theoretical analysis presented the stress and deformation in fiber core within
packages, and forecast the birefringence may be amplified in novel package according to the package structure,
which will support the measurement based on polarization spectrum technique. The experiment result proved
theoretical analysis and shown that the novel side-hole package provided stability support while kept the
advantage of the former side-hole package.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81924L (2011) https://doi.org/10.1117/12.903657
We report a passively Q-switched Yb-doped fiber laser with Cr4+:YAG saturable absorber and get stable
nanosecond pulse trains. Three kinds of laser cavity configurations, including a cladding-pumped ring cavity, a
cladding-pumped linear cavity and a core-pumped linear cavity were studied, and they all can effectively restrain
the generation of Stimulated Brillouin scattering and the generation of self-pulse. Cladding-pumped ring-avity
fiber laser with Cr4+:YAG as saturable absorber inside is established for the first time to obtain stable 1 μs pulse
trains. The amplitude fluctuation and timing jitter are below 5% (rms). Further more, we can also get stable pulse
trains by using a high reflective fiber Bragging grating as a resonator mirror in a cladding-pumped linear cavity
and a core-pumped linear cavity fiber laser respectively. In the cladding-pumped linear cavity fiber laser, the
tunable pulse repetition rate is from 9.1 kHz to 30.3 kHz and the minimum pulse duration is 156 ns. And in the
core-pumped linear cavity fiber laser, the tunable pulse repetition rate is from 15 kHz to 33 kHz and the minimum
pulse duration is 24 ns which much less than those reported before. Although the average output power is only
hundreds milli-Watts now, the laser uses a fiber coupler as the output of pulse trains, it is convinient to boost the
power with a stage of fiber amplifier. This kind of pulse laser can be used as a seed source, and amplified to tens of
Watts for practical applications in the future.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81924M (2011) https://doi.org/10.1117/12.903904
Chemical laser is one of the most widely used high power infrared sources. Thermal deformation of mirrors in a
resonator is a key factor which hinders the improvement of the beam quality in high power chemical lasers, and it has
been a matter of the utmost concern in the design of high power chemical laser systems. Water-cooled technique is one
of the most widely methods employed in cooling mirrors in high power laser systems. Several kinds of water-cooled
mirrors have been studied by researchers in the world. Research teams of the United States and Russia have done a lot of
work and their water cooled mirrors behave very well. In China, the study of micro-channel water cooled silicon mirror
has been carried out by Cheng Zuhai in detail and the research of water jet cooled mirror has been performed by Li Bin.
Both the two types of water cooled mirrors show excellent capabilities in alleviating the thermal deformation of mirrors.
However, the issues that how and to what extent the beam quality is improved when the water cooled mirrors are
involved have not been analyzed so far. In this paper, through numerical simulations, the beam qualities of linear
resonators with various types of water cooled mirrors are analyzed in detail, and the effects of the two types of water
cooled mirrors are compared. The thermal distortion of uncooled Si mirrors is characterized by Zernike polynomials and
the beam quality is characterized with Strehl ratio, β factor, and M2 factor, which degenerates as the beam oscillates in
the distorted resonator. The aberrance of mirrors non-uniformly heated by high energy laser mainly distributes on the
low-even-order Zernike polynomials. When the uncooled Si mirrors are replaced by water cooled mirrors, the distortion
decreases greatly and the beam quality is improved a lot. Although the performance of the water jet cooled mirror on
mitigating distortion is better than the micro-channel water cooled mirror, the resonator made up of two water jet cooled
mirror is not the best structure in improving beam quality. The resonator composed of an uncooled reflecting mirror and
a micro-channel water cooled reflecting mirror has the most prominent capability in improving the beam quality. The
research method of beam quality and some results in this paper are useful for the design of resonators with water cooled
mirrors and the evaluation of beam quality in high power chemical laser systems.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81924N (2011) https://doi.org/10.1117/12.904037
High spectral resolution lidars (HSRLs) have recently shown great value in aerosol measurements form
aircraft and are being called for in future space-based aerosol remote sensing applications. A quasi-monolithic
field-widened, off-axis Michelson interferometer had been developed as the spectral discrimination filter for
an HSRL currently under development at NASA Langley Research Center (LaRC). The Michelson filter
consists of a cubic beam splitter, a solid arm and an air arm. The input light is injected at 1.5° off-axis to
provide two output channels: standard Michelson output and the reflected complementary signal. Piezo packs
connect the air arm mirror to the main part of the filter that allows it to be tuned within a small range. In this
paper, analyses of the throughput wavephase, locking error, AR coating, and tilt angle of the interferometer are
described. The transmission ratio for monochromatic light at the transmitted wavelength is used as a figure of merit for
assessing each of these parameters.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81924O (2011) https://doi.org/10.1117/12.904139
Mesopause wind and temperature is of great importance for the research on atmospheric dynamics. Center for Space
Science and Applied Research, Chinese Academy of Sciences (CSSAR) has developed the first sodium fluorescence
Doppler lidar in China to probe the wind and temperature in the mesopause region (about 75-115km). This lidar system
employs a narrowband CW dye laser and a pulsed dye amplifier to excite sodium atoms existing in the mesopause region,
therefore to induce resonance fluorescence. Atmospheric wind and temperature profiles can be deduced from the
backscattered fluorescence collected by lidar receiver. The CW dye laser used in this lidar has narrowband linewidth
~100KHz with the help of some frequency-selective elements.
Pound-Drever-Hall technique and Doppler-free saturated
spectroscopy technique are applied in this laser to achieve long term laser frequency stabilization. The laser frequency is
locked at sodium D2a line with ~± 2MHz precision for hours. In order to obtain enough energy pulsed laser sent to
mesopause region, a pulsed dye amplifier has been developed to amplify the CW dye laser's power. It has three
amplification stages, output ~1.5W, 30Hz 589nm pulsed laser when the CW laser's power is about 200mW.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81924P (2011) https://doi.org/10.1117/12.900951
This article established the models of detection that groups of scattering particles flux with no relationship. According
to the MIE scattering theory under the generalized, we derived the scattering light intensity of a single aerosol particle scattering
of Gaussian beam and the luminous flux of ahead scattering formula. On the basic of the single particle scattering, we developed
the scattering luminous flux formula of the groups of scattering particles flux, obtained the total population prior to the scattering
luminous flux.Carried out using MATLAB editor and numerical calculation. The single particle flux and mass scattering curve
with the off-axis distance was be simulated. As the results shows that the different scattering angle, the detector receives the flux
is different; in the same axial distance, the luminous flux decreased quickly as the distance to the axiom increased. At the same
time, the luminous flux affected the waist radius largely. Waist radius of the smaller, the smaller flux. It affected the luminous
flux receiving when the groups of particles in different positions.
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Biological and Medical Applications of Photonics Sensing and Imaging
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81924Q (2011) https://doi.org/10.1117/12.895083
The ultrasonic imaging, X-mammography, CT imaging and MRI can be applied into the breast cancer diagnosis(BCD).
But some factors such as the spatial resolution, contrast and
price-performance ratio (PPR) limit their applications. So, a
novel BCD technology, that is, multi-spectral imaging is adopted into this paper. It can get more information of the
breast tumor and higher identity because it combines the advantages of the spectroscopy and the imaging technology.
And in this paper, the multi-spectral light source induced the breast cancer imaging detector(BCID) is designed, the
spectrum can cover from the UV to NIR. Meanwhile, a custom-built multi-spectral imaging spectrometer (MSIS) is also
developed. And, in order to overcome the stray-light of the
light-route system and improve the resolution and
light-passing efficiency of the system, the novel volume holography transmissive (VHT) grating instead of the plane or
concave grating is used as the diffraction grating in this MSIS. Experimental result show that the novel BCD technology
is feasible, it can offer not only the spectral information but also the image of the tumor. The spectrum resolution of the
MSIS for BCID based on VHT grating can reach 2nm. Compared with the others, this BCID has more compact structure,
faster speed, higher PPR and higher resolution and accuracy. Therefore, this BCID has the potential value in the field of
the BCD.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81924R (2011) https://doi.org/10.1117/12.898550
A novel technique based on single photon counting is developed for tracing the non-equilibrium process by recording
the fluorescence lifetime changes over time. Different from the conventional time-correlated single photon counting
(TCSPC) method, our technique uses a 'double-time' time-correlated strategy in the single photon counting, and it can
record a sequence of fluorescence decay curves with nanosecond-scale time interval. The key point of our technique is
to assign the photons to different groups according to the relative time between photon emission and the beginning of
non-equilibrium process. It is achieved by a specially designed setup. In this setup, the instrument response function,
contributed by the photon detector and signal processing circuits, is about 250ps. The time interval between two
adjacent fluorescence decay curves is adjustable in the range of 13.5~157ns, and eight curves can be measured
simultaneously. Compared with the direct waveform recording method, our novel method can provide significantly
better accuracy in the measurement of fluorescence decay curves. An aqueous solution of tryptophan is used to
demonstrate our method with laser induced temperature-jump technique, and the possible improvements are also
discussed. The technique we introduced here has potential applications in the fields of fast biodynamic research, such
as the protein folding/unfolding kinetics.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81924S (2011) https://doi.org/10.1117/12.899517
An analytical theory integrating the Rayleigh-Debye-Gans theory with fractal aggregate theory (RDG-FA) for a
better understanding of the optical properties of fractal-like tissue at a high-resolution scale is present. The
calculated optical properties of tissue are consistent with the reported values. And the optical properties are
related to the fractal dimension and the correlation length. In addition, the exponents of the inverse power law
spectral dependence of scattering coefficient and reduced scattering coefficient are piecewise linearly depending
on the fractal dimension, indicating that the exponents can serve as a tools for distinguishing the different tissue.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81924T (2011) https://doi.org/10.1117/12.899649
In this paper, polarization property of RBCs was discussed by polar decomposition. Experimental results were compared
with a three-dimensional Monte Carlo simulation for the erythrocyte suspensions with the same concentration. And there
is a good agreement for both experimental and simulative results. Furthermore, Mueller matrices were measured for
erythrocyte suspensions with different concentration under 10%, in this condition light coherent phenomena can be
ignored. Using polar decomposition, the conclusion comes out that degree of polarization (DOP) and diattenuator for
erythrocyte suspensions decrease with increasing concentration. Because when suspension concentration increases,
scattering coefficient will be changed increasingly simultaneously and DOP and diattenuator decreases with added
scattering times. These results will be referred as useful information for noninvasive diagnosis of blood.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81924U (2011) https://doi.org/10.1117/12.899879
The accuracy of the calibration model for the single and double integrating sphere systems are compared for a white light
system. A calibration model is created from a matrix of samples with known absorption and reduced scattering
coefficients. In this instance the samples are made using different concentrations of intralipid and black ink. The total and
diffuse transmittance and reflectance is measured on both setups and the accuracy of each model compared by evaluating
the prediction errors of the calibration model for the different systems. Current results indicate that the single integrating
sphere setup is more accurate than the double system method. This is based on the low prediction errors of the model for
the single sphere system for a He-Ne laser as well as a white light source. The model still needs to be refined for more
absorption factors. Tests on the prediction accuracies were then determined by extracting the optical properties of solid
resin based phantoms for each system. When these properties of the phantoms were used as input to the modeling
software excellent agreement between measured and simulated data was found for the single sphere systems.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81924V (2011) https://doi.org/10.1117/12.900124
The widely use of UV radiation led to the demand for improved understanding of the properties of instrumentation
used to measure this radiation. The UV radiometers are mainly influenced by the factors as operating conditions,
environmental conditions and the UV sources to be calibrated and measured. In addition, large errors can occur due to
out-of-band, non-linear, and non-ideal cosine or spatial response of the UV meters. Through a new designed
measurement system for cosine response property, we do some measuring experiments to 21 kinds of UV radiometers
and calculate the relative deviation of each UV meters. The cosine errors are existed universally. It is recommended that
keeping the UV source closing to a point source and perpendicular to UV detector when it is measured is very important.
We also design and fulfill an experimental system to reflect the measuring errors of UV radiometers when measuring
sources and calibrated sources are mismatched. The results show that if the measurement is of a broadband source, it is
wise to unify the measuring and calibrated source or the two sources have similar spectral distribution. If that is not
possible, we can calculate the spectral mismatch correction factor and spectral matching characteristic factor to correct
the measuring data. All the works above are to let the users in appropriate usage of UV Radiometers in a standardized
and comparable way and make the measurement quantities more accurate.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81924W (2011) https://doi.org/10.1117/12.900150
Due to highly scattering of light in biological tissues, the inverse problem of fluorescent molecular tomography (FMT) is
ill-posed by nature. Overcoming this difficulties requires regularization of the solution. Nevertheless, to choose a proper
regularization parameter is not an easy task in practice. This work applies a hybrid regularization method in
reconstruction. Instead of choosing a termination point for the original large-scale problem, this method achieves a
reliable solution by inner Tikhonov regularization on a projected subspace problem. The choice of regularization
parameter is realized in an iterative scheme. Numerical simulations are implemented to evaluate the performance of the
algorithm. Results are also compared with those of truncated singular value decomposition (TSVD) and least square QR
(LSQR). It is indicated that this hybrid method can reduce the computation time, as well as improve location accuracy of
the fluorescence target in heterogeneous media.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81924X (2011) https://doi.org/10.1117/12.900238
Osteoarthritis (OA) is one of the most prevalent chronic diseases which badly affected the patients' living
quality and economy. Detection and evaluation technology can provide basic information for early treatment. A
variety of imaging methods in OA were reviewed, such as conventional X-ray, computed tomography (CT),
ultrasound (US), magnetic resonance imaging (MRI) and near-infrared spectroscopy (NIRS). Among the
existing imaging modalities, the spatial resolution of X-ray is extremely high; CT is a three-dimensional
method, which has high density resolution; US as an evaluation method of knee OA discriminates lesions
sensitively between normal cartilage and degenerative one; as a sensitive and nonionizing method, MRI is
suitable for the detection of early OA, but the cost is too expensive for routine use; NIRS is a safe, low cost
modality, and is also good at detecting early stage OA. In a word, each method has its own advantages, but
NIRS is provided with broader application prospect, and it is likely to be used in clinical daily routine and
become the golden standard for diagnostic detection.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81924Y (2011) https://doi.org/10.1117/12.900344
The variation of the wavefront aberration with accommodation was investigated based on the eye model of
Gullstrand-Le Grand. The anterior lens radius was optimized at different accommodation to focus the image at the retina,
and the RMS and PV wave-front error of human eye were compared at different accommodation. The PV value of
wavefront aberration from 0.718 waves increases gradually to 0.904 waves and RMS value from 0.21 waves to 0.26
waves when accommodative stimuli varies from 0 to - 5 diopters. The change of PV value is 0.186 waves which is less
than the Rayleigh diffraction limit λ/4, and the change of RMS is 0.05 which under Marechal diffraction limit λ/14.
Therefore, the change of the wavefront aberration caused accommodation can be ignored when wavefront aberrations
in the human eye are corrected with surgery or wearing glasses.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 81924Z (2011) https://doi.org/10.1117/12.900550
Light based treatments offer major benefits to patients. Many of the light based treatments or diagnostic
techniques need to penetrate the skin to reach the site of interest. Human skin is a highly scattering medium
and the melanin in the epidermal layer of the skin is a major absorber of light in the visible and near infrared
wavelength bands. The effect of increasing absorption in the epidermis is tested on skin simulating phantoms
as well as on a computer model. Changing the absorption coefficient between 0.1 mm-1 and 1.0 mm-1 resulted
in a decrease of light reaching 1 mm into the sample. Transmission through a 1 mm thick sample decreased
from 48% to 13% and from 31% to 2% for the different scattering coefficients.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819250 (2011) https://doi.org/10.1117/12.900710
High temperature blackbody BB3500M is used as the primary standard of spectral irradiance at the National Institute of Metrology (NIM). In order to find out whether BB3500M is suitable or not in the realization of the spectral irradiance
scale, we investigated the temperature property of blackbody. On the other hand, a full description of the property of BB3500M can help us to evaluate the uncertainty due to BB3500M. In the experiment, feedback control mode was used to guarantee the temperature stability during the whole process. We measured the temperature drift in an hour, which is needed in transferring the spectral value to the standard lamp. Results show that the temperature change is less than 0.6
K when the temperature is near 3020 K. Also, we measured the uniformity of the bottom of the radiator of BB3500M,
the result showed that the non-uniformity is less than 0.5 K in the effective area around 2870 K.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819251 (2011) https://doi.org/10.1117/12.900790
The quantitative analysis of the effect of aberrations in human eye on vision has important clinical value in the correction
of aberrations. The wave-front aberrations of human eyes were measured with the Hartmann-Shack wave-front sensor
and modulation transfer function (MTF) was computed from the wave-front aberrations. Contrast sensitivity function
(CSF) was obtained from MTF and the retinal aerial image modulation (AIM). It is shown that the 2nd, 3rd, 4th, 5th, 6th
Zernike aberrations deteriorate contrast sensitivity function. When the 2nd, 3rd, 4th, 5th, 6th Zernike aberrations are
corrected high contrast sensitivity function can be obtained.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819252 (2011) https://doi.org/10.1117/12.900820
Based on the thermo-elastic mechanism of a pulsed laser in adipose tissue with inclusions, the physical model of generation and transmission of the ultrasound was established. The transient responses of the single pulsed laser interacting with adipose tissue were presented by means of numerical simulation, meanwhile the corresponding stress field and the transmission of the resultant ultrasound were also investigated. By analyzing the laser-induced ultrasonic waveforms in different positions, we found that when the laser acts on the adipose tissue with inclusions, the
inhomogeneity of the tissue leads to different ultrasound modes. This can be attributed to the difference of the optical absorption coefficient between adipose tissues and inclusions. The larger optical absorption coefficient of inclusion in the adipose tissue, the narrower of the full width at half maximum of laser ultrasound signal waveform. Full width at half
maximum of laser ultrasound signal waveform of a pure adipose tissue is wider than that of the adipose tissue with inclusions. The resultant ultrasound signal waveform has larger amplitude in the inclusions with larger optical absorption coefficient than in the pure adipose tissue. The laser ultrasound signal waveform of the adipose tissue with inclusions has
a multiple-interface reflected wave. These results can provide valuable information about further research on methods
and techniques of ultrasonic noninvasive detection of biological organization.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819253 (2011) https://doi.org/10.1117/12.901074
The internal components of optical Airy beams are numerically analyzed and experimentally verified. The Airy beams
can be divided into several different areas, and the isolated and the interactional components are investigated in detail. The Poynting vector and the angular momentum are employed to describe the evolution of the internal components of optical Airy beams during propagation. The results show that each component bears different functions and the optical
properties are attributed to the interaction of the internal components. The angular momentum can not be self-recovered to keep conservation during propagation when it is broken artificially. The unbalanced angular momentum does not influence the optical propagation properties of Airy beams.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819254 (2011) https://doi.org/10.1117/12.901075
When the pupil is dilated in dim light the higher-order aberrations increase and degrade badly visual performance.
So it is important that the wave-front aberrations of human eyes for scotopia vision with large pupil were developed.
Rod cells are dominant work for scotopia vision. Rod cells distribute in the periphery. The density of rod cells is
highest at 20ºvisual field and it drops by 50% at 50° visual field. Therefore, from the distribution of rod cells, the
research is significant for monochromatic aberrations of the eye across 50ºhorizontal visual field. Aberrations of the
human eyes in the horizontal visual field were measured with Hartmann-Shack wave front sensor. The
characteristic of third to tenth order Zernike aberration rms both temporally and nasally out to 50° is as follows:
considerable differences occur among subjects in the pattern of aberrations, particularly for the dominating
second-order aberrations; The third to tenth order Zernike aberrations increase with the visual angle, but the
increscent magnitude decreases as the Zernike order increases; in despite of imperfect symmetry, the increscent
magnitude is the same on the whole; the third-order Zernike aberrations increases up to 2.2 times from 0° to ±50°visual angle, the forth-order up to 1.6 times, and the fifth to tenth order up to 1.5 times.
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Yonggang Cui, Terry Lall, Benjamin Tsui, Jianhua Yu, George Mahler, Aleksey Bolotnikov, Paul Vaska, Gianluigi De Geronimo, Paul O'Connor, et al.
Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819255 (2011) https://doi.org/10.1117/12.901078
In this paper, we discuss the design of a compact gamma camera for high-resolution prostate cancer imaging using
Cadmium Zinc Telluride (CdZnTe or CZT) radiation detectors. Prostate cancer is a common disease in men.
Nowadays, a blood test measuring the level of prostate specific antigen (PSA) is widely used for screening for the
disease in males over 50, followed by (ultrasound) imaging-guided biopsy. However, PSA tests have a high falsepositive
rate and ultrasound-guided biopsy has a high likelihood of missing small cancerous tissues. Commercial
methods of nuclear medical imaging, e.g. PET and SPECT, can functionally image the organs, and potentially find
cancer tissues at early stages, but their applications in diagnosing prostate cancer has been limited by the smallness of
the prostate gland and the long working distance between the organ and the detectors comprising these imaging systems.
CZT is a semiconductor material with wide band-gap and relatively high electron mobility, and thus can operate at room
temperature without additional cooling. CZT detectors are photon-electron direct-conversion devices, thus offering high
energy-resolution in detecting gamma rays, enabling energy-resolved imaging, and reducing the background of
Compton-scattering events. In addition, CZT material has high stopping power for gamma rays; for medical imaging, a
few-mm-thick CZT material provides adequate detection efficiency for many SPECT radiotracers. Because of these
advantages, CZT detectors are becoming popular for several SPECT medical-imaging applications.
Most recently, we designed a compact gamma camera using CZT detectors coupled to an application-specific-integratedcircuit
(ASIC). This camera functions as a trans-rectal probe to image the prostate gland from a distance of only 1-5 cm,
thus offering higher detection efficiency and higher spatial resolution. Hence, it potentially can detect prostate cancers at
their early stages. The performance tests of this camera have been completed. The results show better than 6-mm
resolution at a distance of 1 cm. Details of the test results are discussed in this paper.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819256 (2011) https://doi.org/10.1117/12.902431
Since computer tomography (CT) image has been widely applied in clinic diagnostics, while for many applications the
information directly provided by CT images is incomplete corrupted by noise or instrument defect, there has great
demand to further the processing methods for improving the CT image quality. Among all image features, the edge
profile of clinic focus has obvious influence on accurately translating CT image. In this paper, the wavelet filtering
algorithm based on modulus maximum method is put forward to extract and enhance the CT image edges. Edges in the
brain lobe CT image can be outlined after wavelet transform, during which the wavelet assigned as the first order
derivative of Gauss function. Further manipulation through maximum threshold checking to the modulus have been
attenuated the pseudo-edges. After segmented with the original CT image, the edge structure has been distinctly
enhanced, and high contrast is achieved between the brain lobe microstructure and the artificially established edges.
The proposed algorithm is more efficient than the common first order differential operator, for the latter it even
deteriorates the edge features. The algorithm proposed in this article can be integrated in medical image analyzing
software to obtain higher accuracy for symptom interpretation.
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Proceedings Volume International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, 819257 (2011) https://doi.org/10.1117/12.903318
Video endoscopes play an important role in clinic practice for gastrointestine and bronchial tracts. Using these video endoscopes, a depressing type of early cancer which has recently been focused on can be identified with change in color tone such as reddening or discoloration. Some hemoglobin color enhancement processing algorithms have been developed to make this slight color tone change clear in real-time. In this paper, we will introduce a new algorithm which has been partially incorporated into a commercial endoscope system AQ-100. The basic principle of the algorithm is to adjust the RGB components based on the IHb value. Through Matlab simulation result and application feedback in clinic practice, this partially incorporated algorithm is confirmed effective in both simulation and clinic practice. Though the complete algorithm has a better effect in simulation, it still has some problems to be resolved before it can be applied into clinic practice.
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