This PDF file contains the front matter associated with SPIE Proceedings Volume 13231, including the Title Page, Copyright information, Table of Contents, and Conference Committee information.

In this paper, photonic nanojet (PNJ) is applied to the field of particle manipulation, and further research is carried out based on single microsphere, dual-microsphere, and two-layer microsphere. First, the single microsphere model is analyzed to reveal its photonic nanojet generation mechanism and manipulation effect for nanoparticles, but it can be found that its manipulation effect is limited in some directions. Then, a dual-microsphere model is introduced, which effectively improves the manipulation effect by increasing the symmetry of the structure, improving the manipulation accuracy of the particles and the ability of multi-channel manipulation by the manipulation of pumping phase. Finally, a two-layer microsphere structure is designed to further increase the channel width and improve the particle trapping efficiency and manipulation flexibility. This study provides new ideas and methods for the development of particle manipulation, and provides reliable means for micromanipulation and biological sample analysis in biomedical fields.

In order to solve the problem of fragility of optical fibers, the extraction mode and extraction protection of the lead-out section of the optical fiber embedded in carbon fiber composite material was studied. The fsFBG sensor was embedded into the carbon fiber composite laminate by prepreg laminates manual laying, and the carbon fiber composite material was formed using a vacuum bag-assisted molding method in a heated curing oven. During the test, the fsFBG sensor was laid axially at different angles to the carbon fiber filaments in the unidirectional prepreg laminates, and embedded between the layers of carbon fiber composite, and the cross-section of the molded material was observed through the microscope, and it was found that when the sensor axially was parallel to the carbon fiber filaments, the resin-rich area around the fiber was the smallest. The research conclusions can provide a certain technical reference for the implementation of optical fiber detection of composite material.

A detailed analysis regarding the surface roughness of Side-polished Fiber (SPF) has been presented in this work using the Gray Level Co-occurrence Matrix (GLCM) technique. The flat areas of the SPF surface exhibited texture characteristics with higher mean values of contrast and entropy, and correspondingly lower values for the angular second moment (ASM), homogeneity, and correlation parameters. Such attributes corresponded to the smaller residual thickness on the flat areas for the polished surface of the fiber optic. Similarly, a stronger intensity for the light transmission with uneven distribution of gray levels along with the appearance of fine texture was also observed with their rich local features primarily oriented in a direction parallel to the fiber-core. Employing the Random Forest (RF) method of feature importance ranking which was based on the Gini coefficient and out-of-bag error estimation, this study assessed the sensitivity of various GLCM texture parameters in classifying roughness levels of the SPF polished surfaces. A feature subset comprising variance, ASM, entropy, and contrast was identified as an optimal set. Utilizing this subset, a validation experiment for analyzing the roughness of the SPF polished surfaces has been conducted via RF classification. The results demonstrated an RF classification accuracy of 95.65%. This research explores the impact of surface roughness on the mechanism of light coupling in SPF optic sensors employing environmental materials and its influence on sensor sensitivity. It lays the foundation for reconnoitering ways to precisely identify the high-sensitivity areas on SPF optic surfaces, thereby aiming to focus on the development of a rapidly emerging technology of a micro-probe type "lab-on-fiber" for photonics applications.

In the 0.9 μm & 1.0μm structure pumped in cavity, the resonator contains two thermal lenses in addition to two end mirrors. Based on the propagation circle theory, the focal length of the thermal lens of the quasi-three-level laser in the cavity is obtained. The temperature simulation results of two gain mediums are carried out by COMSOL, there is a serious thermal effect in the gain medium of Nd:GdVO₄ quasi-three-level laser, which limits the improvement of laser performance. Trying to reduce the thermal lens effectthe is first considered. It lays a good foundation for further analysis of the thermal stability cavity (double thermal lens) with double thermal disturbance and its dynamic characteristics.

Near-infrared-II afterglow luminescence phosphors, which holds lower auto-fluorescence and up to 1,000-fold reduction in scattering losses, have achieved great attention as optimal probes for bio-imaging. Er³⁺, Nd³⁺, Ho³⁺ doped fluorides are ideal near-infrared luminescent materials as well as NIR-II persistent luminescence phosphors. Although they have been used for biological imaging, their afterglow luminescence properties are not yet ideal, and their afterglow mechanism still needs further research. Here, we have conducted a detailed study on the afterglow properties of Er³⁺, Nd³⁺, Ho³⁺ doped β-NaYF₄ and provided their persistent luminescence mechanism, providing direction for improving the afterglow properties.

Long afterglow luminescence (LAL) phosphors hold potential for diverse applications. However, too many factors make it impossible to obtain a general afterglow mechanism, which hinders the exploration of the novel afterglow phosphors. Here, we take trivalent rare earth (RE³⁺) doped Li₂SrSiO₄ as an example for research, use X-rays as the excitation source to ensure host-band charging method regardless of the band gap and use RE³⁺ ions as the luminescent centers achieving the stability of emission wavelength in different hosts. The data results indicate that Ce, Pr, Tb, Dy, Sm, and Tm, which are easily variable in valence, exhibit afterglow emission, while Er, Nd, and Ho, which are not easily variable in valence, do not exhibit afterglow emission. A general afterglow mechanism based on the afterglow properties of Li₂SrSiO₄:RE³⁺ was proposed, in which the electrons and holes were generated under X-ray excitation formed excitons, subsequently bound by RE³⁺ where the ability of RE³⁺ ions to bind excitons is determined by their valence change trend.

Currently, the detection techniques for assessing environmental stress in active microalgae are fraught with complexities, expensive, and poor timeliness. Therefore, this paper introduces an algal fluorescence excitation and detection device based on spontaneous chlorophyll fluorescence, aimed at investigating the effects of marine pollutants on algal stress. In the experiments, different concentrations of mercuric chloride (HgCl₂) solution were added to algal samples. Under the pollutants stress, the fluorescence intensity of the algae weakened, and it continued to decrease as the stress time to the pollutants increased; under the same stress duration, higher concentrations of pollutants resulted in faster decreases in fluorescence intensity. Similarly, this device was also used to detect the stress effects of cadmium chloride (CdCl₂) and sodium hypochlorite (NaClO) solutions on Chlorella. This paper proposes a simple, convenient algal fluorescence excitation and detection device for studying the impact of heavy metals and common inorganic substances in bleach on the fluorescence excitation characteristics of Chlorella. Experimental results demonstrate the feasibility of using the proposed algal fluorescence excitation device to detect the concentration and stress time of pollutants stressing the algae.

High-power picosecond lasers have a wide range of applications in high-precision drilling, solar cell cutting, and ultrafast spectroscopy. The main oscillator power amplifier (MOPA) technology is an effective scheme to generate high-power picosecond pulses. The thermal effect of the laser gain medium significantly impacts both the laser power output and beam quality. This paper prioritizes constructing a thermal effect model of the gain medium and simulates the temperature field distribution inside the crystal under different pumping modes. Then the pulse string picosecond laser output was successfully realized using the self-developed picosecond fiber seed laser and a two-stage end-face pumped traveling wave amplifier. The maximum average output power of 26.1 W, 28 W, and 29.6 W was obtained when the pulse string contained 2, 5, and 10 sub-pulses, respectively, corresponding to pulse energies of 130.5 µJ, 140 µJ, and 148 µJ at a repetition rate of 200 kHz.

Femtosecond laser processing is a high-precision method for processing Carbon Fiber Reinforced Polymer (CFRP) composites due to its high peak power and short pulse duration, resulting in low damage. This method holds great potential for application in the aerospace industry. This paper investigates the ultrafast dynamic response mechanism of the polymer matrix (resin matrix) within CFRP composites under femtosecond laser irradiation using a numerical model. The computation of the evolution of electron density in the resin material under femtosecond laser irradiation and the analysis of trends in instantaneous local optical property changes are presented. The prediction of ablation morphology of the resin matrix under different fluences is also included. This study offers guidance for femtosecond laser surface cleaning of CFRP composites.

The Femtosecond Laser-assisted Etching (FLAE) technique represents an optimal approach for fabricating three-dimensional microfluidic channels. In this study, we introduce a novel approach utilizing birefringent crystals for temporal and polarization shaping to generate orthogonally polarized pulse sequences, effectively controlling the polarization dependence of the etching process, and achieving high-precision and high-efficiency microchannel fabrication in fused silica. Experimental results demonstrate that polarization-independent etching can be achieved by manipulating the sub-pulse delays and polarization states. Additionally, we found that four-pulse sequences offer a higher etching rate compared to dual-pulse sequences under the same conditions, thus enhancing manufacturing efficiency. Incorporating slit beam shaping on top of temporal and polarization shaping has successfully adjusted the longitudinal and transverse dimensions of the microchannels, improving their cross-sectional roundness and quality. Overall, we propose a method for fabricating polarization-independent microchannels and optimizing their cross-sectional profiles.

Lasers feature a potential to steer chemical reactions in combustion flames through resonant excitation of precursors, which changes the species ratio for material synthesis. In this study, diamond deposition using an O₂/C₂H₂/C₂H₄ flame with NH₃ additions was investigated under the CO₂ laser excitation of the wagging mode of the C₂H₄ molecules. The diamond crystallinity is restored and improved by the resonant laser irradiation. The diamond crystallinity is restored and improved by the resonant laser irradiation. Field-enhanced thermionic emission current was monitored to determine the diamond incubation time and the subsequent growth. Optical emission spectroscopy (OES) was employed to investigate the emission intensity ratio between CN and CH species in the activation zone. It was found that the emission intensity ratio of I(CN)/I(CH) increases with the NH₃ addition given a fixed laser power density, while the ratio decreases with the augment of laser power density at a fixed NH₃ concentration. A correlation between I(CN)/I(CH) ratio and diamond deposition was established. Large areas of well-faceted and high-phase-purity diamond film could be formed within a short incubation time at a low I(CN)/I(CH) ratio. On the contrary, a high I(CN)/I(CH) ratio results in long incubation time (if diamond nucleates) and deteriorated diamond films. The innovation of this study lies in demonstrating the capability of laser resonance excitation modulation reaction pathways and providing crucial insights into nitrogen addition and resonance laser energy coupling in diamond deposition using combustion chemical vapor deposition.

The synthesis of new materials plays an important role in organic solar cells.The novel selenophene-containing polymer donor was synthezed by using selenophene based on the D18-Cl structure of D-A type. The novel polymer named D18- Cl-2Se shows a more complementary absorption spectrum with a broad-band gap and a suitable energy level with a deeper HOMO energy level. It means the device will have a higher Voc and Jsc. This study provides a good way to design polymer donors by introducing selenophene to construct high efficiency organic photovoltaic cells.

One of the reasons why the current optics used in 193 nm lithography do not have sufficiently high reflectivity and have poor optical timing is the lack of a low-refractive-index material with low absorption, low scattering, low residual stress, amorphous structure, and good aging resistance. In this study, we investigated the effect of the AlF3 content in MgF2-based low-refractive-index materials on the microstructure and optical properties of Mg1-xAlxF nanocomposite coatings prepared by thermal evaporation. Based on these findings, this study successfully solved the problems of large absorption, easy crystallization tendency, and poor aging performance of thermally evaporated AlF3 films. A novel low-refractive-index nanocomposite material with improved absorption reduction, scattering suppression, and aging resistance was obtained, which can be applied to the study of reflective optics for 193 nm lithography.

In recent years, the study of ultrafast electron dynamics within metals has garnered widespread attention. Specifically, the interband transition threshold (ITT) in metal films, a key determinant of material optical properties, is crucial for understanding and designing new photonic materials and devices. This study investigates the effect of metal film thickness on ITT and its underlying mechanisms using transient reflection spectroscopy. It was found that ITT showed a redshift trend as the thickness of gold film decreased to less than 60 nm, a phenomenon attributed to the combined effects of strong electron-electron interactions and surface interface effects. This reveals how film thickness can regulate interband transition behavior in metals, thereby influencing their optoelectronic properties. These findings not only enhance our understanding of the electronic structure and optical properties of metal films but also provide a theoretical and experimental basis for the development of new nanophotonic devices.

Since the rapid development of semiconductor industry, the key nodes keep shrinking and defect detection played a vital role in produce yield improvement. The dark filed detection method has been widely used for un-patterned wafer. In this paper, a model is built for calculating and analyzing the scattering field of particles as defect, based on which the measured configuration is optimized, including the incident angle, polarization and scattering collection channels. Simulation shows the measurement accuracy and precision are improved after the measured configuration optimization, and may provide a reference for further defect detection.

This study employs step concentration technology to significantly reduce the severe thermal effects experienced by Tm: YAG crystals under high-power pumping. Firstly, the thermal distribution and thermal stress of Tm: YAG crystals with three different step concentrations are simulated respectively. It has been observed that the thermal conduction and distribution within the crystal vary with the concentration and length of the crystal. In the experiment, the output performance of LD-pumped Tm: YAG lasers with three different step concentrations was compared. In the continuous operation, the measured slope efficiencies were 35.34 %, 38.34 %, and 40.82 %, respectively. In the Q-switching operation, the slope efficiencies were 10.32 %, 10.87 %, and 12.56 % at the repetition frequency of 300 Hz, and the beam quality factor M2 was 1.63,1.52 and 1.46, respectively.

Exploration of laser interactions with Carbon Fiber Reinforced Polymer Composites (CFRP) is gaining traction in micro-engineering of complex materials. This study harnesses ultraviolet (UV) picosecond pulse laser technology to modify the surface morphology of CFRP. Through a detailed microstructural analysis employing a three-dimensional surface morphology analyzer and scanning electron microscopy (SEM), the effects of UV laser power and scanning speed on CFRP surfaces were examined. The investigation determined that at a constant repetition frequency of 500 kHz, increasing the laser power while maintaining a scanning speed of 800 mm/s led to reduced surface roughness, with Sa and Ra values declining from 15.159 µm and 4.138 µm to 6.473 µm and 3.538 µm, respectively. Furthermore, at a laser power of 9W, a reduction in scanning speed resulted in decreased residual resin, achieving a clean surface at 400 mm/s without resin recast and minimal fiber damage. These results highlight the importance of optimizing laser parameters for effective CFRP surface cleaning, paving the way for improved processing of composite materials.

Vector ray tracing (VRT) model is used to simulate the propagation process of rays entering layered particles. The (1, 2, 2) exiting rays causing one of the primary twin rainbows of the layered droplet are extracted, and the primary rainbow fringe of the rays is obtained. When the core-shell ratio approaches 0, the layered droplet with a tiny core is approximately homogeneous and their rainbow scattering angle curves are highly consistent. According to the number of exiting rays at the same elevation angle in the same scattering section, the rays are partitioned and the hyperbolic umbilical fringe is obtained.

Bioaerosols have a certain impact on environmental quality and human health. In order to quickly identify bioaerosols and carry out timely and effective prevention and treatment. This study will optimize and improve the classical convolutional neural network LeNet-5 model, and combine attenuated total reflection Fourier transform infrared spectroscopy ( ATRFTIR ) technology to classify 15 bioaerosols. By changing the two-dimensional convolution kernel into one-dimensional convolution kernel to adapt to one-dimensional spectral data, the convolution layer and pooling layer are added to optimize the network structure, and the dropout algorithm, batch normalization and ReLU activation function are used to enhance the generalization ability and robustness of the network. The results show that the accuracy of the model reaches 100 % when the training times reach 80 times. Compared with the nearest neighbor ( KNN ) and Partial least squares Discriminant Analysis( PLS-DA ), the accuracy of the improved LeNet-5 model on the test set is significantly improved, showing its excellent performance in the rapid and accurate identification of bioaerosols, which provides new ideas and methods for the rapid and accurate identification of bioaerosols.

Ceramic-reinforced metal materials are indispensable in industrial equipment such as aircraft engines and nuclear reactors, but the difference in coefficient of thermal expansion (CTE) between ceramics and metals limits the service life of ceramic films. The fabrication of transition layers between metal and ceramic films is a common solution strategy, but the process is inevitably complicated, costly, and material-restricted. Here, we use a high-energy laser beam to impact ceramic nanoparticles to modify the metal surface and ultimately harmonize the thermophysical properties at the interface between the substrate and ceramic film. The test results show that the superalloy substrate modified by ZrC and 8YSZ laser additive is favorable for L-YSZ bonding, while the superalloy substrate modified by Al₂O₃ is favorable for Al₂O₃ thin film bonding, and the interfacial adhesion of L-YSZ and Al₂O₃ films was improved by more than 3.6 and 9 folds, respectively

The data obtained from Raman spectroscopy is characterized by high dimension and complexity. In this study, dimensional reduction techniques, including LASSO, random forest, and principal component analysis, were employed to refine the datasets. An optimal model was then constructed using Artificial Neural Networks, which achieved an average accuracy of 0.943 when subjected to 10 times 5-fold cross-validation. Based on the feature importance ranking map of four algorithms, the species differences of five subgroups of leukocytes induced by nucleic acid and protein vibrations were found. The visual representation between feature selection methods and variations in Raman shift characteristics demonstrates the intricate interplay and serves as a robust foundation for our forthcoming “Raman intra-group correlation analysis”.

Laser-Induced Breakdown Spectroscopy (LIBS) combined with traditional mathematical methods for quantitative analysis of material composition often relies on specific prior knowledge, leading to issues such as poor analysis accuracy and weak generalization performance. In order to mitigate the impact of prior knowledge on the analysis method and simultaneously enhance analysis accuracy, this study proposes a 1d CNN model based on the ResNet-18. The model is specifically designed for the quantitative analysis of four elements (Cu, Mo, P, S) in steel. Subsequently, to better serve edge computing scenarios, the research focuses on lightweight processing of the algorithm model, making it easily transferable to low computational power devices. A total of 40 steel samples were collected for constructing the dataset, and optimizations were made regarding the loss function utilized during model training. Experimental results indicate that the proposed method achieves RMSE values of 0.0096 for the four elements. Even after reducing the model parameters by almost 90%, the RMSE for the four elements remains at 0.0131, demonstrating no significant performance degradation. This validates the effectiveness of the proposed method.

The wave manipulation in the waveguide is of great importance for integrated terahertz (THz) signal processing and communication. Here, a design of metallic waveguide with meta-holes (MWMH) is proposed to realize focusing in the waveguide with unlimited focal length. When the MWMH is used to realize focusing with a focal-length of 45 mm, the gain at the focus can reach 26.8 dB and the focusing efficiency is 52.77% of the incident power. The full width at half maximum (FWHM) is 3 mm, and the depth of focus (DOF) is 22 mm. Furthermore, the MWMH for focusing with a focal-length of 10 mm and 0 mm are demonstrated, as illustrations of its flexible wave manipulation functions. The proposed MWMH with flexible wavefront manipulation functions opens up new possibilities for the development of THz integrated photonics devices, and has great potential in non-destructive testing, spectral imaging, and 6G wireless communication.

Cross-linked polyethylene cable has the advantages of safety, convenience, and simple maintenance, and has gradually become the main power transmission cable. However, the internal moisture content of the XLPE insulation sheath of buried cable will lead to the decline of power cable insulation performance. The accurate detection and location of water content distribution in power cables is very important for the safe operation of the power system. This paper presents a method of measuring the cable interior using reflection terahertz time-of-flight tomography. However, the tolerance of the terahertz optical path is very important for the usability of the test device. Through the test results of the angle tolerance of the terahertz optical path system in the insulating sheath, the angle incident tolerance of the system is finally obtained, and the location and area of the leakage defect of the insulating sheath are accurately measured within the range of the angle tolerance, the potential application of terahertz time-domain spectroscopy in cable detection is verified in this paper

The non-equilibrium plasma jet at atmospheric pressure produces low-temperature plasma in an open environment, which has broad application prospects. Based on the emission spectrum of the argon plasma jet, this paper studies the variation of irradiance, electron temperature, electron density, and metastable particle number when the gas flow rate and axial distance are used as independent variables, respectively. The results show that with the increase in gas flow rate, the irradiance generally shows an increasing trend. At the same gas flow rate, the irradiance decreases with the increase of axial distance. With the increase of gas flow rate, the electron temperature decreases gradually, and the electron density increases gradually at the same axial distance. At the same gas flow rate, the electron temperature and electron density increase first and then decrease with the increase of axial distance. The number density of metastable particles increases with the increase of gas flow rate, and increases, decreases, and then increases with the increase of axial distance.

In order to investigate the impact of the resonator type on the beam quality of a solid-state laser, a diode pump module was built using Nd:YAG as the gain medium. A basic resonator, measuring 185mm in length, was then assembled with two different types of mirrors. There are five types of mirror fitting modes: flat mirror with flat mirror, flat mirror with concave mirror with a curvature radius of 4000mm, flat mirror with concave mirror with a curvature radius of 3800mm, concave mirror with a curvature radius of 2800mm with convex mirror with a curvature radius of 3000mm, and concave mirror with a curvature radius of 2600mm with convex mirror with a curvature radius of 3000mm. To determine the correlation between the peak power of the laser output and the beam quality of various resonators, the peak power and spot size were measured, and the M2 factor was calculated and analyzed.

Spatial distributions of pump and oscillating beams are altered by thermal effect in high-power end-pumped solid-state lasers. This study revealed a specific pump power range within which the pump beam and fundamental-mode oscillating beam almost completely overlap in the Nd: YAG gain medium under thermal effect, which results in high optical-optical conversion efficiency and high beam quality. When pumping power ranges from 105 W to 115 W, the output power and the optical-optical conversion efficiency are higher than 42 W and 38%, respectively, with beam quality less than 2.3. The maximum output power and optical-optical conversion efficiency are 45 W and 42.1%, respectively, with M_x ²=2.14 (M_y ²=2.32) when the pump power is 109 W. Outside of this range, the values rapidly deteriorate.

The side of the lens placed in the AA region has distortion and a large lateral vision dark in the part of the lens. Cut one lens into two from the middle and place them at the seams of screens to achieve seam elimination. The darkened area of the picture is smaller, while reducing costs. Further, because this traditional lens usually needs to open a separate mold, the cost of mold opening is high, and it is difficult to match the seam elimination of various cases in one mold, thereby increasing the cost. The electronically controlled liquid crystal lens does not need to open the mold, and the production cost is low. The use of electronically controlled liquid crystal lens can further reduce the cost, and the scheme is simulated and verified.

For the current fiber grating displacement sensor range is small and the sensor can't display the displacement value on the spot, a large range of self-displaying fiber grating displacement sensor is proposed, through all levels of the transmission mechanism in the sensor, converting the amount of stretch in the wire rope into stress on the fibre grating, which causes the change of the central wavelength of the reflected light of the fiber grating. The sensor adopts double grating structure, which can achieve automatic temperature compensation. Sensor internal mechanical digital display structure, through the sensor digital display window can be directly observed in the field to the displacement value. Calibration experiments and static characteristic analysis of the sensor, the results show that: the measurement range of the sensor for 0 ~ 1000mm, the accuracy can be within ± 5mm.

In this study, by redesigning the membrane layer structure of the traditional Kretschmann model of the surface plasmon resonance sensor, the problem of small measurement range of the solution concentration of the original structure and the reduced sensitivity of the sensor when measuring liquids with higher concentration was solved. In this paper, the transfer matrix method was adopted to calculate the attenuated total reflection intensity, and the surface plasmon resonance curve was obtained using the angular modulation method, and its feasibility was verified by simulation. The final experimental results show that for common transparent liquids such as NaCl solution, glucose solution, sucrose solution, etc. The membrane layer structure proposed in this paper can expand the originally small concentration measurement range to a full concentration range measurement, which is very effective for expanding the measurement range.

When using optical fiber sensors to monitor the health of carbon fiber composite structures, it is necessary to study the optimal arrangement of fiber optic sensors on composite structures. According to the performance characteristics of the composite structure, a finite element simulation model was constructed, and the weak position and modal mode shape matrix of the model were obtained by analyzing the modal changes of the model. Based on the Modal Assurance Criterion (MAC) criterion, the modal order and the number of sensors are optimized, and the target modal matrix required for sensor arrangement is obtained. Finally, based on the improved Gray Wolf Optimizer (GWO), an optimal arrangement model of optical fiber sensor was proposed, and the optimal arrangement scheme of the sensor was obtained.

In this paper, we propose a novel optical encryption scheme of vector light field based on the large-format metagrating device. The pixelated metagratings are utilized as vector light field modulation units to modulate the phase of incident light pixel by pixel, so as to precisely manipulate the propagation directions of directional vector light beams and accurately project them to specific positions in image space. In combination with the ciphertext amplitude information provided by image masks, the optical target images are eventually reconstructed on a given imaging plane. We experimentally fabricate large-format metagrating array elements (90 mm×90 mm) and satisfactorily accomplish the tasks of image encryption encoding and optical decoding, capturing the reconstructed images with fine visual quality. Metagrating elements are simple to design and can be easily fabricated on a large scale with low cost, contributing to the promotion and practical applications of optical encryption technology.

A new method for fabricating porous cone by temporal-spatial shaping femtosecond laser–assisted molding is proposed. In this method, high-depth micro cone arrays can be efficiently fabricated by Bessel beam with long focal depth. besides, combining with sugar to be sacrificed, porous cone can be molded with the fabricated cone template. Furthermore, hydrophilic bottom layer is realized with the Hydrophilic treatment by Poly-dopamine. This may have potential applications in Solar-driven seawater desalination.

In this paper, a directly pumped passively Q-switched Nd³⁺ -doped phosphate fiber laser using Cr⁴⁺:YAG as a saturable absorber is reported. The Nd³⁺ -doped phosphate fiber preform with minimal internal defects were prepared by the double-peeled isolation extrusion method and drawn into optical fibers. The core-clad size of the fiber was 234/356 μm, with a transmission loss of 1.1 dB/m at 1053 nm. Subsequently, a passively Q-switched fiber laser was constructed based on the homemade Nd³⁺ -doped phosphate fiber, and the effects of parameters such as the reflectivity of the output coupler mirror, the transmittance of the saturable absorber, the length of the fiber, and the pumping power on the characteristics of the output laser pulse were investigated. After optimizing the key parameters, the laser achieved a peak pulse energy of 388 μJ and a maximum peak power of 21.8 kW. The results provide fundamental theoretical and experimental guidance for the development of passively Q-switched fiber lasers with high peak power, demonstrating significant practical value and theoretical significance.

High manganese steel is widely used in rotary tillage blades, and its wear resistance is general. After laser biomimetic processing, the wear resistance of rotary tillage can be improved. This study used CO₂ continuous laser to perform biomimetic laser biomimetic surface processing on high manganese steel, and investigated the effect of biomimetic scale distribution on wear performance. The experimental results show that as the number of biomimetic scales increases, the wear of the sample decreases and the friction coefficient increases, indicating that biomimetic scales provide protection for high manganese steel. Finally, the study revealed the wear resistance mechanism of biomimetic scales.

In order to understand the current research status of cigarette filters using laser drilling methods for ventilation and harm reduction, and provide ideas for related work on new product development and improvement, this article reviews the factors affecting the ventilation effect after filter punching, the mathematical model and CFD simulation study of cigarette smoke flow, and the study of cigarette draw resistance, ventilation rate and key substance release rules. The results show: The most popular online laser drilling technology for filters has good ventilation stability, but there are still some problems such as uneven hole shapes and side-cut oval holes, which make the ventilation effect of cigarette filters deviate from the original design intention. Furthermore, the mathematical correlation between cigarette filter laser drilling parameters - filter ventilation - key substance release - cigarette sensory quality should be found to reduce the trial and error cost of cigarette manufacturers and play a guiding role in the development and production of traditional cigarettes. Perforated cigarettes have the effect of reducing scorch and harm, but perforating holes will have a negative impact on the appearance quality of some cigarette products. Making perforated cigarettes more beautiful while ensuring ventilation and reducing char in cigarettes will be the future direction of laser perforation of traditional cigarettes.

In this paper, a correction method based on U-Net convolutional neural network to correct the morphology of conical and spherical microlens with period from 30 μm-100 μm is proposed. Maximizing the utilization of the nonlinear characteristics of the convolution neural network and the encoder/decoder to capture the characteristics of the different scales, we employ the U-net network to describe the inverse process of lithography. By constructing and training the UNet convolutional neural network, on the basis of learning a large amount of data, we can obtain the inverse process model of direct writing lithography. After optimization, the average absolute error of conical microlens is decreased from 0.68 μm to 0.22 μm. For spherical microlens array, the full-width-half-maximum of intensity distribution is improved from 18 μm to 10 μm.

A four-frame imaging ultra-fast CMOS image sensor for inertial confinement fusion diagnosis is studied. Based on the 0.18 μm standard CMOS technology, the design and simulation of the CMOS image sensor are completed. And the logic reliability of the CMOS imaging sensor based on the in situ pixel division scheme is simulated and verified. The simulation results show that the CMOS image sensor can capture four images at a time, and the time resolution of each image could be controlled at about 300 ps, the frames interval between two adjacent images could be controlled at about 600 ps.

Mulberry silk fabrics are very popular due to their soft lustre, comfortable handle and smooth texture. Currently, the traditional textile testing methods are deficient to provide a fast and sensitive directional detection way or quantitative characterization data to study different process stages of the textile. Here, we used crepe de chine as silk samples for microscopy detection. Both confocal fluorescence microscopy and fluorescence lifetime imaging microscopy (FLIM) methods have been applied into observing samples at different process stages to obtain their surface morphology and fluorescence lifetime distribution. The confocal results showed that the samples had autofluorescence under excitation at several wavelengths. The fluorescent intensities of different samples from a series of process stages of the silk manufacture or the air-dried pure sericin were obtained under the 640 nm excitation, which was used in the following FLIM experiments. FLIM results showed that in undyed group, the lifetime values of the raw silk fabric were around 2400 ps. The lifetime of the sample with partial sericin left were similar to those in the raw silk fabric while the intensities were decreased. The optical properties of the dyed fabrics were similar to the undyed group, but their lifetime values were lower than those of the undyed group, suggesting that the silk fabrics had different optical properties due to the factors including the residual amount of sericin and dyeing condition. Briefly, FLIM can provide a non-destructive method for real-time quantitative investigation of the silk fabrics at different process stages, providing information for parameters such as the residual amount of sericin.

When the traditional processing method is used to process hard and brittle monocrystalline silicon, it will encounter a variety of problems, so it is necessary to use laser processing method. Laser processing is a new processing method, and there are few relevant studies on laser processing silicon convex microlens array, and no polishing. Therefore, the morphologies of silicon microlens arrays fabricated by femtosecond laser are studied in this paper. The results show that when the fixed green light is 100KHz, the power is about 36W, and the speed is 1500mm/s, the 3D dynamic processing effect of femtosecond laser is better. The morphology compensation research is carried out, and the surface roughness is greatly improved by using mirror jet polishing.

The direct design method is employed to fashion the double free-form surface of the COB light source, addressing issues of limited energy utilization and uneven illuminance or intensity in the light source's illumination area. This approach integrates the principles of edge lighting, Snell's law, and Fermat's principle to directly undertake the secondary light distribution design for the COB light source, without relying on optimization algorithms. This ensures swift calculations and attains a high energy utilization rate along with excellent illuminance and intensity uniformity. Using a COB surface light source with a diameter of 25 mm as an illustrative case, a free-form surface lens with a central height of 38 mm was crafted to yield rectangular light spots exhibiting uniform illuminance and intensity distribution on the receiving surface. The resulting root mean square error for intensity stands at approximately 0.38, while the energy utilization rate reaches 91.68%. Similarly, the root mean square error for illuminance is around 0.25, with an energy utilization rate of 90.26%.

Aiming at the problems of the high cost, poor real-time performance, and the inability to perform vector flow velocity detection of current flow velocity sensors, this paper proposes a vector flow velocity sensor based on wavelength-division multiplexing of fiber Bragg gratings (FBGs) embedded in the flexible films. Using the small size, low cost, high sensitivity of FBG, and the elasticity, waterproofness, and corrosion resistance of flexible materials, this sensor effectively achieve rapid measurement of underwater vector flow velocities. It demonstrates great potential in applications such as marine environment monitoring, underwater auxiliary navigation, and underwater robotics.

Temperature measurement plays a pivotal role in both everyday life and industrial production. The utilization of flexible temperature sensors has gained significant attention due to their exceptional flexibility, which allows for greater adaptability in various application environments. This paper introduces a straightforward and efficient approach to manufacturing a graphene-based flexible temperature sensor. Laser-induced graphene (LIG) was synthesized from phenolic resin (PR) irradiated by flat-top shaping femtosecond laser. The resulting LIG was thoroughly characterized using SEM, Raman spectroscopy, and XPS. The flexible temperature sensor was prepared based on LIG. The sensor has a sensitivity of 0.78% /°C and a linear response over a temperature range of 25-75°C. The application potential of PRbased LIG extends to human physiological health monitoring, wearable devices, and various other fields.

A method for designing an end-to-end shaping network of a differentiable light field is introduced to address challenges related to illumination inconsistency and limited energy utilization in the domains of augmented reality and indoor lighting. Distinct from traditional shaping algorithms, this method eliminates the need for pre-optimization, boasts a straightforward principle, and demonstrates exceptional capabilities in achieving high uniformity and energy utilization. Furthermore, its versatility allows for application to a diverse array of arbitrary shaping patterns. Simulation results reveal that diffraction patterns exhibit remarkable consistency under multi-color LED irradiation, with an energy utilization rate approaching 96% and a significantly low RMSE value of 0.03.

Driven by the miniaturization of integrated electronics and the increasing demand for ultrafast information transmission in communication systems, investigations into functional devices based on spoof surface plasmonic polaritons (SPPs) have garnered significant attention. However, the characteristics of spoof SPPs are related to geometric parameters of the unit structure, the functions of devices that composed by unit structures cannot be altered by changing the sizes of structures. The next focus to be investigated is the reconfigurable and active control of the device. Herein, we report a reconfigurable and direction-controllable coupler for spoof SPPs to spatial radiated waves. By changing the rotation angles of unit cells, it becomes possible to independently control the reflection phases. Through manipulation of different phase gradients, various reflection angles can be achieved at a fixed frequency. The results confirm that the proposed coupler holds great promise for applications in reconfigurable functional devices.

In this paper, combined with the idea of phase optimization and computational imaging, an optimization design method of diffraction microstructure of large field of view diffractive lens is studied. The off-axis aberration of the diffractive lens is regulated, and the back-end image restoration algorithm is combined to finally achieve a large field of view and high-quality imaging effect. Based on the quadratic phase profile, the microstructure height of the diffractive lens is numerically optimized. A quadratic phase diffractive lens with an aperture of 500 μm and a focal length of 500 μm is designed, fabricated and experimentally verified. Finally, it is proved that this method can achieve 60° (±30°) large field of view diffraction imaging effect.

In recent years, processing with femtosecond lasers for micromachining has emerged as a new technology with significant roles in high-end manufacturing. By loading phase onto the incident femtosecond laser through diffractive optical elements (DOEs), it can form the desired light field distribution through diffraction. In response to various issues and limitations of traditional DOE processing techniques, this paper proposed a new DOE processing method based on femtosecond laser direct writing on fused silica. Utilizing the saturation phenomenon of fused silica during femtosecond laser processing, craters with dimensions of several hundred nanometers can be processed on the surface of fused silica. Through the control of the parameters of femtosecond laser, the processing of craters with high precision and high controllability on fused silica with can be achieved. This phenomenon can be used to realize the processing of DOE phase distribution according to the specific laser wavelength. Compared to traditional methods, this processing method has the advantages of high precision, high efficiency, and high flexibility. The DOEs processed by this method based on fused silica have high diffractive efficiency, can be used in various high-fluence applications and have good diffraction effects.

In the current research domain, the development of Fiber Bragg Grating (FBG) evanescent field sensors faces challenges of high manufacturing costs and poor repeatability. To solve this problem, we developed a novel FBG evanescent field sensor, which combines FBG with multi-mode fiber (MMF) to excite evanescent field through a simple fiber fusion technology, thus realizing a low-cost and high-resolution detection scheme. In a high reflectivity FBG, multiple cladding modes are excited when the forward guidance mode in the multimode fiber is coupled with the backward guidance mode of the FBG in the cladding. The evanescent field fiber sensor is highly sensitive to the surrounding refractive index without changing the fiber structure, and exhibits a full width half height (FWHM) of 78 pm and a quality factor (Q-factor) of 1.9×10⁴ at the standard cladding mode resonance, which is superior to most reported evanescent field fiber sensors on these parameters. The proposed fiber grating sensor significantly expands its application potential in the fields of biosensing and chemical analysis.

In the aerospace, military industry and energy sectors, there is a growing demand for dynamic pressure measurement in high-temperature environments. At present, common electrical pressure sensors are difficult to meet the requirements of high temperature and high frequency response at the same time. Combining the characteristics of high temperature cofired ceramics (HTCC) and the structure of fiber optic Fabry-Perot sensor, this paper proposes a realization method of fiber optic Fabry-Perot pressure sensors based on HTCC and high-temperature sintering technology. Based on the theoretical analysis of HTCC materials, a high-temperature resistant pressure sensing film based on HTCC was designed and fabricated. The ceramic sintering process is further used to package and integrate HTCC sensor. The specific experimental results are as follows. Static pressure sensitivity is 1.80 nm/MPa. The goodness of fit linearity reached 0.9998. The resonant frequency of the sensor reaches 495.8 kHz. The survival time at high temperature of 800 °C is more than 80 h. The sensitivity to temperature is 0.0046 nm/℃. The sensor studied is suitable for dynamic pressure measurement in high temperature environment.

The implementation of low wavenumber Raman detection relies on high-performance optical filtering components. Reflective volume Bragg gratings exhibit excellent wavelength and angular selectivity, suitable for the narrowband, high-efficiency filtering requirements of low wavenumber Raman detection. Based on the derivation of the Kogelnik theory, an analysis of the simulated reflective VBG diffraction efficiency and bandwidth influencing factors is conducted. Finally, specific parameters are determined through the analysis to design a reflective holographic filter with a peak wavelength of 785nm and a bandwidth of 0.4nm. Raman spectra as low as 50cm-1 can be measured.

Advances in bandgap engineering of various III-V compound semiconductors have led to innovative infrared detector architectures such as InAs/GaSb barrier-type structures. This barrier-type structure detectors are characterized by enhanced carrier transport optimization, a significant reduction in interface state density, and superior thermal stability, alongside a notable reduction in dark current and noise levels. These improvements not only substantially enhance the fundamental electrical characteristics of semiconductor devices but also expand their application flexibility and environmental adaptability through meticulous bandgap engineering. This article reports a study on optoelectronic properties based on a graded barrier InAs/GaSb T2SLs long-wave infrared detector for the first time, with detailed analysis from two aspects: electrical and optical properties. The surface leakage current is measured through variable area testing. The study correlates effective bandgap and activation energy across temperatures, providing insights into bulk dark current components. In addition, the temperature dependence of blackbody responsivity is also analyzed.

This study adopts the method of fracture morphology to reveal the fatigue failure mechanism of fiber bragg grating sensors under cyclic loading. The mirror district, mist district, and sawtooth district of the fiber optic cross-section confirm that it follows the fracture law of hard and brittle materials. The failure is caused by initial defects on the surface of the optical fiber, which induce cracks during the process of increasing stress. When the crack size reaches the critical value, it leads to fracture. Due to the higher brittleness of the optical fiber compared to the coating layer, the grain boundary friction intensifies during cyclic loading, leading to grain boundary fracture. In addition, cyclic loading accelerates stress corrosion, resulting in additional damage and promoting crack propagation. Through the analysis of experimental data, an S-N curve function model of the fiber bragg grating sensor was established under the conditions of constant temperature at 300℃, 10Hz vibration frequency, and 0.1 stress ratio. The results showed that its fatigue strength limit was about 330MPa. This provides a basis for scientifically predicting the service life of fiber bragg grating sensors in practical applications.

In order to solve the problem of wavelength shift of the laser monitor, a device based on billet split lens for measuring wavelength is designed. Taking the red light emitted by He-Ne laser as reference, measuring the distance of the interference fringes, the width of the cut part of the split lens is calculated, and then the wavelength of the measured is calculated. The device has the advantages of simple operation and high measurement accuracy, which is expected to be applied to the measurement of the emission wavelength of the laser monitor, and is of great significance to the optimization of the working performance of the laser monitor.

As a new type of DBR tunable laser, Modulated Grating Y-branch (MG-Y) laser has great advantages in the field of optical fiber sensing and demodulation. However, due to the complex tuning relationship of MG-Ylaser and the wavelength switching interval of 50GHz cannot meet the requirements of the existing FBG demodulators, this paper proposes a characterization method of MG-Y laser based on k-means clustering combined with combinatorial optimization algorithm, which the final test time is about 8 hours. Theoretical and experimental tests show that the designed MG-Y laser has an wavelength interval of 0.02nm in the 40nm range, with a better wavelength stabilitythan0.006nm and an output power flatness within 1.6dBm. Compared with the direct traversal current method, this method reduces the amount of test data by 90% and improves efficiency by more than 50%.

The output waveform and the lasing optical spectrum of a sinusoidally modulated gain-switched Fabry-Perot diode laser (LD) is experimentally observed and investigated. Under a weak modulation, the LD maintains single-mode oscillation, with the linewidth of a single mode increasing due to carrier density fluctuation, which is independent on modulation frequency. In the vicinity of the relaxation oscillation frequency with a strong modulation, the LD outputs a regular pulse with duration of hundreds of picosecond and emits multimode spectrum with spectral half-width at half-maximum (FWHM) of approximately 2 nm, where the mode competition is suppressed and the gain is shared. As the modulation frequency further increases to twice the relaxation oscillation frequency, the laser output pulses exhibit a period doubling of the modulation frequency. The LD output pulse with spectral FWHM of 2 nm is introduced into a Michelson-type interferometer, the measured coherence length is around 184 μm with a moderate average power of 11 mW. Such a short coherence laser is suitable for application in low-coherence interferometer.

The process defects involved in phase-shifted fiber grating fabrication by the scanning exposure method are analyzed, which include phase shift impreciseness, stained point on phase-mask, unstable UV energy, non-uniform motion of scanning platform and so on. And the fabrication process defects of are divided into three destabilization situations: πphase-shift deviation, random phase shifts, and grating chirping. The mechanical simulation of phase-shifted fiber grating and distributed feedback fiber laser based on the coupled-mode theory and transmission matrix methods are carried out to analyze the effect of disturbance-induced defects during fabrication on the spectrum of phase-shifted fiber grating and the lasing performance of distributed feedback fiber laser.

Organic light-emitting diodes (OLEDs) utilizing full-fluorescent emissions, exhibit notable advantages, including costeffectiveness and excellent color stability. Additionally, managing excitons within fluorescent WOLEDs further complicates the matter. In this study, this article had successfully developed high performance fluorescent OLEDs by precisely controlling the concentration of phosphorescent-sensitized red fluorescent emitters within the emissive layer. The emissive layer consists of a blend of phosphorescent sensitizer Ir(ppy)₃ with red fluorescent emitter DCJTB. The resulting red fluorescent OLEDs ’s current efficiency is 10.88 cd/A, power efficiency is 11.39 lm/W. At a brightness of 1000 cd/m^2, the efficiency values are 3.98 cd/A, 6.38 lm/W. The proposed strategic approach offers a promising path towards practically deploying high-performance red fluorescent WOLEDs in academic and industrial contexts.

In this study, a series of three-color and four-color white organic light-emitting diodes (WOLEDs) were fabricated by controlling the movement of the exciplex emission recombination zone (RZ) and adjusting the intensity of yellow exciplex emission layers. These devices were based on blue exciplex emission layers (TCTA: TPBi), green exciplex emission layers (TCTA:PO-T2T), and yellow exciplex emission layers (TAPC:PO-T2T), in addition to red phosphorescent materials. The three-color WOLED demonstrated maximum power efficiency (PE) of 14.49 Im/W, current efficiency (CE) of 12.69 cd/A, and external quantum efficiency (EQE) of 5.58%. The four-color WOLEDs attained a high color rendering index (CRI) of 93 at 7V, with color coordinates of (0.3869, 0.4050). As far as we know, this represents one of the better data points where a CRI of 93 has been achieved in a WOLEDs using only one phosphorescent material.

Utilizing dual-end pumping technology within semiconductor lasers, a continuous output of 0-18.92W was realized in a Tm: YAP laser, with a consistently measured central wavelength of 1989.01nm. Next, build a Ho: YAP acousto-optic Q-switched dual pulse laser resonator with a repetition rate of 1kHz, Ua=9V, Ub=6.5V, and Tb=2 μs. Tc=2 μs. When the pumping power is 18.92W, the maximum average power output of the Ho: YAP dual pulse laser is 1.89W, with a center wavelength of 2117.64nm and a line width of 0.64nm. The dual pulse laser is stable, with both pulse widths of 68.80ns and a pulse interval of 2 μs.

The structure of the porous transport layer in PEM electrolysis for hydrogen production is reconstructed using computed tomography, and liquid flow is simulated and analyzed with the Boltzmann method, focusing on how pore structure and porosity influence the hydrodynamic characteristics of the porous transport layer. Results indicate that pore structure and porosity influence the permeability, flow rate, and uniformity of liquid water flow distribution in the porous transport layer, which further impacts the stability of the PEM electrolyzer and hydrogen production efficiency. This provides a theoretical foundation for optimizing the design of the porous transport layer in PEM electrolysis for hydrogen production, and demonstrates the potential of combining CT reconstruction technology with fluid simulation in studying the porous transport layer.

By constructing a mathematical model of a four layer fiber optic grating sensor, the influencing factors of strain transfer in welded encapsulated metalized high-temperature fiber optic grating sensors were studied and analyzed. The relationship between single physical quantity and dual parameters and axial strain transfer rate was studied, and the theoretical analysis was validated using finite element method. The results showed that the strain transfer rate was 91.1% at a temperature of 300 ℃, and the Poisson's ratio had a relatively small effect on strain transfer. The thickness was inversely proportional to the strain transfer rate. In contrast to the welding layer, the smaller the elastic modulus of the coating, the more conducive it was to strain transfer. When the length of the welding layer was 4mm, the strain transfer rate reached 99.5%. Theoretical and simulation results showed high consistency, with an error within 0.004. This verified the correctness of the strain transfer function model selection and theoretical calculation, and provided a theoretical reference for further optimizing the selection of sensor materials and welding design.

At present, the laser methane sensors used in the market are designed according to the requirements of AQ 6211-2008 standard. Compared with the standard, there is still some room for improvement in detection accuracy, response time, and power consumption of laser methane sensors. Therefore, a new type of laser methane sensor based on TDLAS methane gas detection technology has been developed. By conducting error tests on three sensors, there is a good linear relationship between the sensor test values and the standard gas, indicating that the sensors have high testing accuracy. The power consumption of the sensor has been tested, and the maximum power supply distance can reach 6 km. Test the sensor response time for less than 15 seconds. The above indicators are all better than the standard requirements. The application of this sensor will improve the detection accuracy and stability of coal mine safety monitoring system, which is of great significance for ensuring coal mine safety production.

The performance of power batteries directly impacts the range, safety, and reliability of pure electric ships. Currently, mainstream power batteries primarily consist of lithium-ion batteries, including lithium iron phosphate and lithium ternary variants. However, temperature significantly affects the performance of lithium batteries. In low-temperature environments, lithium-ion battery cycle life deteriorates significantly, battery power characteristics rapidly decline, usable capacity diminishes notably, and challenges such as low temperature charging and lithium precipitation arise. At high temperatures, lithium battery self-discharge rates increase, capacity loss is pronounced, battery aging accelerates, and issues like overheating leading to thermal runaway, combustion, and explosion emerge. Hence, thermal management of lithium batteries is a critical area requiring breakthroughs in current technology. This paper reviews research progress in lithium battery thermal management system (BTMS) globally, detailing methods and advancements in low-temperature and high-temperature thermal management, and outlines future development trends in lithium BTMS.

This paper presents an infrared optical fiber spectrum sensor for detecting the rust of elevator wire rope. The sensor is composed of incident infrared fiber, receiving infrared fiber, fiber collimator, fiber angle regulator, condenser, fiber coupler, thread rod and fiber fixer. One end of the incident infrared fiber is connected with the fiber coupler, and the other end is connected with the fiber collimator. One end of the receiving infrared fiber is connected to a fiber coupler, and the other end is coupled to a condenser. The condenser is used to collect the beam of light emitted by the incident fiber and reflect the beam of light through the wire rope, and transmit the focused beam to the receiving infrared fiber. The horizontal angle of the incident infrared optical fiber collimator is adjusted by the optical fiber angle regulator, and the distance between the infrared incident optical fiber collimator and the infrared receiving optical fiber condenser is adjusted by the threaded rod. The incident infrared fiber, receiving infrared fiber, optical fiber collimator, optical fiber angle regulator, condenser, optical fiber coupler and threaded rod are fixed by the optical fiber fixer to form a whole, which is the sensor used for the rust detection of the elevator rope.

Quasi-continuous wave laser is widely used in the field of cigarette ventilation and char reduction, and laser perforation makes cigarette filters have stable ventilation rate and ventilation and char reduction effect. In this paper, in order to investigate the morphological characteristics and forming mechanism of laser perforation of cigarette filter splicing paper, scanning electron microscope and optical microscope are used to observe the laser perforated samples of cigarette, measure and analyze the size of the small holes of laser perforation of cigarette filters, and measure the physical parameters of the perforated cigarettes, such as the ventilation rate and the suction resistance, and come up with the following conclusions: (1) the microstructure of cigarette filter splicing paper is more complicated, with strong anisotropy, different paper materials after perforation have stable ventilation rate and ventilation and coke reduction effect. Strong anisotropy, different paper material perforation after the morphology of different features, by the laser perforation equipment and the paper itself characteristics of the multiple effects, improve the quality of perforation morphology can be from the laser perforation equipment and papermaking process in two aspects; (2) ventilation holes in the optical microscope is similar to the oval inside and outside of the two holes, there is a white edge between the inside and outside of the holes, the decision to ventilate the effect of the inner holes of the area, and therefore should be made to make the white edge As small as possible, under the premise of ensuring the ventilation performance of cigarettes as far as possible not to affect the appearance of the quality of cigarettes; (3) the filter receiving paper in the perforation there is a "side hole" phenomenon, "side hole" of the morphology of the normal holes with a certain degree of difference, which will have a certain effect on the ventilation effect of the filter of cigarettes. This will have a certain effect on the ventilation effect of cigarette filters. (4) Comparison of the physical property test results of the perforated samples with the results of optical microscope observation shows that there is a correlation between the ventilation rate of cigarettes and the area of the ventilation holes, and the measured ventilation rate and total ventilation rate of cigarette filters and the measured area of the ventilation holes conform to the quadratic curves.

In order to realize the micro vibration detection of mechanical parts, a set of vibration detection system of Swept Source Optical Coherence Tomography (SS-OCT) system is set up in this paper. the vibration detection principle of optical fiber SS-OCT system is analyzed, and the numerical relationship between optical path difference and spectral signal oscillation frequency of OCT system is obtained. The phase difference method of All-phase Fast Fourier transform (apFFT) spectrum analysis and OCT ranging technology are combined to improve the displacement resolution of the system. Through the calibration of the nanoscale displacement table, the system can achieve the nanoscale displacement resolution, and the feasibility of the SS-OCT system for vibration detection is verified.

Extraction of the line structured light center in the online structured light visual measurement system is a key technology, and its purpose is to accurately extract the strip at the center of the line structured light in the image. This is crucial for subsequent measurement and analysis. However, traditional methods (such as the gray center of gravity method and Steger algorithm) may not be able to extract effective laser light strips quickly and accurately when processing a large number of pixels. In order to solve this problem, this paper proposes an improved line structured light center extraction method based on the gray center of gravity method. This method first uses the neighborhood threshold method to identify the light strip area in the selected area, and then conducts in-depth analysis through the gray center of gravity method, and finally extracts the specified image coordinates to obtain complete information of the laser light strip. The experimental data indicates that this method can effectively enhance the efficiency of light strip extraction.

The combustion of industrial furnace is an indispensable part of metal smelting and industrial power generation. In order to solve the problem of full combustion of coal in the furnace, it is necessary to accurately control the CO concentration in the industrial furnace. In the high temperature and high pressure environment of the industrial furnace, we choose the direct absorption spectroscopy method in the tunable semiconductor laser absorption spectroscopy technology to measure the CO concentration. In this paper, a high temperature blackbody furnace is used to simulate the high temperature and pressure environment in an industrial furnace, direct absorption spectrometry is used to measure the concentration of 5000ppm CO gas in 100℃-1100℃ environment. When the temperature in the blackbody furnace is 100℃-600℃, the relative error of experimental measurement is controlled within 10%; When the temperature exceeds 700℃, the relative error of measurement exceeds 20%, the measurement error is large, which can not meet the requirements of industrial application measurement accuracy.

To address the issue of low matching accuracy between the prior spectral library obtained through vertical nadir acquisition and the measured spectra acquired through tilted acquisition, a spectral curve inversion algorithm based on a kernel-driven BRDF model is proposed in this paper. This algorithm is capable of inverting spectral curves at specified angles, thereby enhancing the matching accuracy with spectra obtained through tilted acquisition. Through a field multi-angle spectral measurement system, we collected multi-angle spectral information of common features used in military target recognition, such as dry grasslands and desert camouflage nets. Subsequently, spectral feature analysis was conducted, and the performance of various inversion algorithms was compared. The results indicate: (1) The reflectance of both types of features changes individually in a similar trend with variations in detection angles. (2) Curve inversion algorithms demonstrate favorable results for tilted curves, with coefficients of determination above 0.83 between inverted and measured spectra at tilted angles. (3) According to Spectral Angle Mapping (SAM), the inversion algorithm reduces spectral angles between inverted spectra and measured spectra at tilted angles, thereby enhancing spectral matching accuracy. This study enriches the relevant field of multi-angle remote sensing and holds theoretical and practical significance for high-spectral target matching detection.

Red light and infrared light are commonly employed in the acquisition of Photoplethysmography (PPG) signals due to the differential absorption properties of human tissues across various wavelengths. Hemoglobin (Hb) absorbs red light (660nm), which upon passing through the skin, gets absorbed and reflected by the skin. Minute fluctuations in pulse movements modulate the absorption of red light, enabling the estimation of heart rate. Infrared light (940nm), on the other hand, is predominantly transmitted through the skin and other tissues due to its lesser absorption by water and tissues. This property allows infrared light to penetrate deeper into tissues and traverse through the blood. The attenuation of infrared light can be attributed to its absorption by blood in the vessels under skin, which facilitates the estimation of blood oxygen saturation (SpO2). Thus, a single sensor that combines the red and infrared light can provide insights into both heart rate and blood oxygen levels, making it a standard application in medical monitoring and health tracking. In the experiments, fast Fourier transform (FFT) analysis was employed to obtain the hemoglobin SpO2 values. The optimization process focused on several variables: (i) the total collection period; (ii) processing of hexadecimal to decimal conversion and overflow values; (iii) sampling rate of the data; and (iv) the resolution of spectral analysis outputs. The optimization was intended to identify the minimum sampling rate and the minimum number of discrete data points at which the SpO2 accuracy could be secured. The findings revealed that with a sampling rate of 15 Hz and a collection period of 4.3 s, the SpO2 accuracy can be maintained at an acceptable level by 64-point FFT computation.

Temperature is one of the fundamental physical quantities in physics and a critical parameter in characterizing an object's properties. Therefore, temperature measurement has always been a crucial topic in industrial production. The existing temperature measurement technologies cannot measure the continuous temperature field distribution inside the objects, which is a important issue in industry. X-ray imaging provides a potential solution. In this work, X-ray imaging was used to measure the temperature field distribution of objects. A novel nonlinear fitting curve model was employed to reconstruct temperature from images and compare it with actual measurements. The practical effect of X-ray non-contact temperature measurement was discussed. The method was suitable for higher temperature conditions and facilitates noncontact temperature measurement of high-temperature objects, providing a new solution for detecting the internal temperature field of high-temperature in industry. Additionally, it provides an experimental way to verify the existing temperature field models.

Concept of utilizing W-type GeO2-doped silica fiber for high power coherent supercontinuum (SC) is firstly proposed. We reveal how the core diameter, inner cladding diameter and GeO₂ doped content of outer cladding dramatically influence dispersion characteristics of W-type fibers. W-type fiber with outer cladding of 80 % GeO2 doped silica and 5 μm core diameter can achieve all normal dispersion (ANDi) from 1.2 to 2.8 μm, and the fiber with such large core diameter can withstand high power SC. SC are numerically simulated in the W-type fiber pumped with femtosecond pulse at 1960 and 1560 nm. The results suggest that the fiber can produce SC with high coherence spanning from 1020 to 2530 nm. The Wtype silica fiber not only enables high power coherent SC generation in the near-infrared range but also facilitates the implementation of an all-fiber system.

Aiming at the point cloud data of hull shape obtained from laser scanner, which is characterized by large scale and many noise points, as well as the problems of low registration efficiency, slow convergence speed and poor robustness of traditional point cloud registration algorithms, a complex hull shape laser point cloud registration method based on improved iterative nearest point algorithm (ICP) is proposed. Firstly, a filtering method is used to denoise and the voxel filter is used for downsampling. After that, the key points are extracted from the hull shape point cloud by Intrinsic Shape Signatures algorithm (ISS), further construct the Fast Point Feature Histogram (FPFH) and find the corresponding point pair relationship, and use the random sampling consistency algorithm to filter the incorrect corresponding point pairs. Then, the Quaternion method is used to calculate the transformation parameters to complete the initial registration. The k-dimensional tree structure is established to enhance the operational efficiency of ICP algorithms, and aiming at the problem that ICP algorithm converges slowly and is prone to incorrect corresponding point pairs, the point-to-plane ICP algorithm by combining with distance constraints and normal vector included angle constraints proposed for fine alignment. The experiment indicated that in the registration experiments of ship hull laser point cloud data, compared with the traditional ICP algorithm, the proposed method has a higher registration efficiency and shortens the registration times, and can efficiently and accurately complete the large-scale ship hull shape point cloud registration.

The photoelectric stabilized platform is used for target tracking, which keeps the visual axis of the device stable and accurately points to the target through the servo system, but it is affected by the disturbance torque, which causes the tracking performance to decline. In order to overcome the influence of disturbance torque, the disturbance observer is applied in the three-loop servo control system of the photoelectric stabilized platform to improve the tracking accuracy of the photoelectric stabilized platform. The simulation analysis of the improved servo control system shows that the tracking position error range is reduced from 0.006° to 0.001°, which proves the feasibility of the method.

In the process of fire rescue, laser radar and millimeter wave radar are the best technical choices for the reconnaissance task of obtaining map information in unknown environment. Based on the technical characteristics of laser radar and millimeter wave radar, a large amount of smoke is generated in the limited test environment. Through the comparative test, the influence of smoke on laser radar and millimeter wave radar mapping is analyzed, so as to explore the technical application method of radar mapping

Pulsed Plasma Thrusters (APPTs) are constrained by the limitations of propellant material and supply methods, which result in low system efficiency and propellant utilisation rates. Notably, the spark plug, which serves as the inductive plasma source for the main discharge, consumes energy that does not effectively contribute to the thruster's impulse and also impacts the operational lifespan of the thruster. This study aims to explore effective methods to improve the performance of the thruster system through laser coupling, this study experimentally investigated the performance of a laser-EM coupled pulsed plasma thruster using polytetrafluoroethylene (PTFE) and aluminium as propellants under various energy conditions. A comparative analysis with the performance of a conventional APPT revealed that the laserEM coupled APPT can utilize propellants, including metallic materials, and the ablation of the propellant can be precisely controlled by the laser. Under the same initial energy conditions, although the single pulse ablation mass is reduced, the system specific impulse and efficiency are significantly enhanced.

MXene, with their exceptional optical and plasmonic properties, exhibit broad application prospects in the fields of sensors and optoelectronic devices. A deep understanding of the carrier dynamics within these materials is crucial for optimizing the performance and design of these applications. Here, we employ transient absorption spectroscopy to systematically analyze the ultrafast dynamic characteristics of two-dimensional Ti₃C₂T_x MXene across ultraviolet, visible, and near-infrared bands. The experimental results reveal in detail the complex dynamic processes of electrons in MXene materials under photoexcitation, including significant ground state bleaching effects, excited-state absorption phenomena, and absorption changes closely related to surface plasmon resonance. Furthermore, by selecting and analyzing the kinetic curves of these processes, we gain a deeper understanding of the carrier dynamics behavior of MXene materials at different time scales. These findings not only significantly enhance our comprehension of the light absorption mechanisms of MXene materials but also hold extreme value in guiding the innovative applications of highperformance optoelectronic devices based on MXene in key technological fields such as energy conversion and thermal management.

Weak light environment poses challenges for target detection. It is difficult for the existing target detection algorithms to track the target in the noise-flooded image. In order to improve the accuracy of the target detection algorithm, it is necessary to process the low-light image first. In this paper, a time-domain filter is used, which combines the dynamic detection of time-domain filter and the denoising ability of spatio-temporal filter to provide help for target detection under low light conditions. This paper focuses on the motion compensation filtering by calculating the associated parameters of the front and back frames through multi-direction edge filtering. The down-sampling differential pyramid is used to avoid the discontinuity of the partition blocks. A convolutional strong edge detection method based on multi-directional template is proposed to improve the edge detection function of traditional spatial filtering template. Finally, kernel correlation filtering (KCF) is applied to the image to realize target detection. By comparing the target detection rate and accuracy before and after filtering, it is proved that the algorithm can effectively improve the detection ability of low-light level image. By comparing with other algorithms, it is proved that the proposed algorithm has more advantages than the uncombined traditional algorithm.

Moving target detection is always a hot research field, which is widely used in many fields, especially in military field. In this paper, we use the gyroscope data to quickly screen the moving objects under the motion camera. Firstly, the feature points are extracted according to the curvature feature of the point target. Then, the camera is calibrated to obtain the external and internal parameters of the camera, and the gyroscope error is corrected according to the original dense background track recorded by fitting the gyroscope data, and the obtained correction value is compensated back to the original image coordinates of the feature points, to obtain the corresponding world coordinates. Then the point correlation of the feature points in the world coordinate system is carried out to form a stable track. Finally, according to the motion characteristics of the feature points, the moving target trajectory is selected to realize the detection of the moving target under the motion camera. According to the experiments in this paper, the feasibility and high efficiency of the gyroscope modified screening target in the world coordinate system can be proved.

In order to address the challenge of high-precision angular deformation measurement of the star sensor bracket for the Macau Science satellite-1, a PSD-based autocollimation method for angle measurement using common-path polarized light difference was proposed previously. A measurement system was developed, enabling high-precision measurement of the bracket's angular deformation under vacuum and high-low temperature conditions. However, deficiencies such as large non-linear errors in PSD and significant effects of scattered light on measurements within the system were identified. To address these challenges, this study proposes a CMOS-based angle measurement method using common-path polarized light difference. Additionally, a centroid algorithm for spot detection was designed, and simulations were conducted using Zemax. Finally, a setup was constructed, and calibration experiments based on PSD and CMOS were carried out across different measurement ranges. The results revealed that within the measuring range of ±500″, the maximum calibration deviation for PSD was 3.1″, while for CMOS, it was 1.2″. These findings demonstrate the enhanced measuring range and precision achieved by the proposed CMOS-based method.

Vibration detection and analysis can provide raw data for early detection, diagnosis, and prevention of mechanical faults. Meanwhile, fiber Bragg grating(FBG) sensors offer advantages such as strong anti-interference capability, high precision, and high signal-to-noise ratio compared to traditional electro-mechanical sensors. Addressing the limitation of traditional fiber optic grating-based vibration sensing systems, which is constrained by the Nyquist theorem, an FBG-based OFDR vibration sensing system is proposed. Leveraging the Doppler effect, this system achieves the capability of measuring high vibration frequencies at low repetition rates. Additionally, an adaptive orthogonal demodulation algorithm is introduced to mitigate the spectral broadening issue caused by the non-negligible grating length. Experimental results demonstrate that this system can measure vibration frequencies as high as 30 kHz with a repetition rate of 10 Hz. Comparative analyses between experimental and simulated data validate the performance advantages of the proposed demodulation algorithm.

Multispectral object detection technology has important application prospects in the fields of autonomous driving and so on. Conventional multispectral object detection algorithm rely solely on deep neural networks to learn multispectral image sample information, lacking the guidance of prior knowledge, and not fully utilizing infrared, visible, and other spectral information, resulting in decreased accuracy of object detection in complex scenes. To address this problem, this paper proposes an object detection algorithm based on infrared visible sample augmentation and illumination guidance. The algorithm adopts the MMDetection framework and extracts multispectral object features based on a designed sample augmentation method based on the fusion of positive and negative samples in multispectral images. Based on a designed adaptive weight allocation method guided by illumination, it enhances the algorithm's adaptability to the lighting environment. Finally, through the design of a multi-task loss function, it achieves high-precision and robust object detection in complex scenes. Experimental results on datasets such as FLIR and M3FD show that the proposed algorithm has significant advantages over comparative algorithms such as CFR_3 and GAFF in terms of average detection precision.

The article introduces the methods for detecting road surface smoothness and the working principle of the laser profile analyzer. Through specific applications in engineering practice, the advantages of the laser profile analyzer in road surface smoothness detection are discussed. And discussions were conducted on the design of detection schemes, analysis of detection results, and other aspects, providing reference for the application of laser cross-section instruments in road smoothness detection.

The electrical mixer is limited by operation bandwidth and parallel processing capacity, and is suffering from increasingly serious electro-magnetic interference. By introducing photonic properties, microwave photonic technology has many advantages compared to the traditional microwave technology, such as low loss, large bandwidth, high parallel processing capacity, anti-electromagnetic interference and so on. In this work, a Stimulated Brillouin Scattering (SBS) based microwave photonic mixer with high image rejection capacity is proposed. Due to the high wavelength-selectivity and wideband tenability of the SBS process, the image rejection ratio of the mixer exceeds 40dB over the IF range of 80 MHz to 2 GHz and the RF range of 2 to 40 GHz.

In this paper, a Fabry-Perot interferometer filled with ultraviolet curing adhesive sensitization of high sensitivity fiber optic temperature sensor is proposed, by filling the F-P cavity with ultraviolet curing adhesive, due to the high coefficient of thermal expansion of the ultraviolet curing adhesive, the traditional fiber optic temperature sensor is achieved by primary sensitization. Combined with the optical vernier effect sensitization mechanism for secondary sensitization of the fiber optic Fabry-Perot interferometer, the sensor achieves a compact polymer-core sensing probe fiber optic interferometer structure and exhibits a temperature detection sensitivity of -17.55 nm/℃. This paper uses the F-P cavity peak phase spectral tracking algorithm for the vernier response spectrum collected by the vernier effect to obtain the peak spectral tracking and realise the high sensitivity detection.

This paper proposes an optical image encryption method based on RNA encoding and computational ghost imaging. Four sets of random sequences obtained from Chen's hyperchaotic system are used to construct the speckle matrix required for calculating the ghost imaging system. The initial values of the hyper chaotic system is provided by encrypted images, by which one image corresponds to one encryption is achieved. RNA codons are used to encode and calculate the chaotic sequence, increasing the key space and improving the security of the system. The speckle matrix and target image are inputted into the computational ghost imaging system, as RNA encoding and codon substitution on the image received by the barrel detector are performed to obtain an encrypted image. This method effectively reduces the size of transmitted keys, improves transmission efficiency, and enhances the security of the system. It has certain reference and reference significance for optical based image transmission and encryption.

The bubble is a part of the particle, and the study of the scattering characteristics of the bubble is of great significance to the optimization of the particle measurement technology. Current light scattering techniques are less efficient for calculating large bubbles. In this paper, the scattering characteristics of ellipsoidal bubbles are studied. The scattering Angle and intensity distribution characteristics of bubbles irradiated by axial Gaussian beams are simulated by geometric optical approximation method. The effects of diffraction, divergence factor and phase shift are considered in the calculation, the influence of Gaussian beam waist radius on scattering intensity distribution is analyzed.

Aircraft icing poses a serious threat to flight safety. In response to the problem of limited sensing range and susceptibility to external interference of traditional ice sensors, a distributed aircraft ice detection method based on phase-sensitive optical time-domain reflectometer (φ-OTDR) system and fiber Bragg grating (FBG) array is proposed, in which a mapping relation between wing vibration frequency and its icing state is established. Experiments have shown that the system can effectively measure vibration signal of piezoelectric transducer (PZT) with a signal-to-noise ratio (SNR) over 51.58 dB. In a wind icing tunnel, an experiment of a complete icing and de-icing process on a wing model was conducted, which shows that by measuring the vibration frequency of the wing model, its icing state can be detected.

We introduce a novel deep learning-based framework to decrease data acquisition time and enhance the 3D reconstruction resolution of sparse view THz-CT. Using asymmetric convolution blocks and channel attention mechanisms, our network ASE-UNet effectively suppresses terahertz image artifact in extreme sparse views. Furthermore, a preprocessing step involving integrating bandwidth power effectively converts time-domain data into detailed spatiotemporal data. The results show that our method delivered superior reconstruction quality and is more efficient in data usage than traditional iterative algorithms

New super-resolution optical imaging methods are emerging, but there are still deficiencies in the experiments to verify these methods. The problem is that when we need to image and verify experimental samples, we do not know the Ground Truth of the samples. Therefore, we propose a method to generate experimental samples with known Ground Truth. For imaging optical methods, we introduce a super-resolution nanoprobe that can scan in two dimensions, and in the detection optical path of the actual wide-field experiment, we modify the point spread function of the system to a single helix point spread function. By using a series of single helix point spread function samples collected from the wide-field imaging experiment, combined with the scanning of the optical needle, we finally generate images scanned by the optical needle using this generation method. These images are composed of single helix point spread functions, and their Ground Truth is known. Therefore, it is proved that using our method to generate images of some samples captured by imaging systems with known Ground Truth is a feasible scheme for imaging technology verification.

We design, fabricate, and characterize a polarization-insensitivity 8-bit optical tunable delay line (OTDL) on the 3-μm-thick silicon-on-insulator (SOI) platform, employing low-loss waveguide spirals and rapid-calibrated integrated optical switches. The spirals integrate mode converters and Euler bends, have high fabrication tolerance, low wavelength sensitivity, and propagation loss as low as 0.32 dB/cm within 140 nm bandwidth. The 4-cm-length waveguide spiral has polarization dependent loss (PDL) less than 0.3 dB within 140nm bandwidth. OTTDL utilizes optical switches with extinction ratio (ER) of up to 50 dB for path switching. The switch integrated multimode interferences (MMIs), thermo-optic phase shifter and variable optical attenuators (VOAs). VOAs not only enhance the delay signal-to-noise ratio, but also facilitate rapid calibration in OTDLs. With maximum delay time of 3570 ps and resolution of 14 ps, our OTDL holds significant promise for future applications, particularly in the integration of delay line arrays for microwave photon radar systems.

As LCD televisions advance towards larger dimensions and ultra-high-definition resolutions, the issue of elevated energy consumption has become increasingly conspicuous. In pursuit of further power reduction, the industry has explored numerous avenues, including advancements in LCD panel transmittance and the integration of Local Dimming techniques. Amidst these efforts, the field-sequential color liquid crystal display (FSC-LCD) technology has garnered significant interest for its inherent power-saving attributes. Nonetheless, FSC-LCD technology has yet to attain mass production, partly hindered by the backlight's RGB LEDs' diminished luminous efficacy. This investigation introduces RGB Mini-LEDs as a replacement for conventional LEDs in the backlight system of FSC-LCDs. The research encompasses the experimental prototype's hardware design and assembly, leading to an energy efficiency index assessment. The outcomes reveal that the prototype successfully attains a top-tier energy efficiency rating, fulfilling the GB24850-2020 standards for a fourth-tier efficiency index applicable to 4K displays (3840*2160 resolution) and demonstrating substantial energy conservation capabilities.

In the air-breathing engine test, the component concentration in the inlet flow field is a key parameter, but there is a lack of online methods to measure this parameter in real time. Tunable diode laser absorption spectroscopy (TDLAS) is a mature low-cost non-contact flow field measurement technology, but it is primarily utilized for small-scale laboratory applications. To measure the component in the mesoscale hypersonic flow field in real time, this paper conducted the engineering application research of TDLAS component measurement and achieved the TDLAS application in measuring the component and temperature in the mesoscale hypersonic flow field. We developed a multi-component detection system consisting of multiple lasers, collimating mirrors, and detectors, measured data is transmitted to the computer for processing and can realize uninterrupted long-term monitoring. Through on-site testing, it has been shown that the designed system solves the problem of long-distance optical path layout and signal transmission in vacuum environments. It can measure signals normally under testing conditions, reflecting the state changes of corresponding components in the TDLAS optical path in the vacuum chamber in the flow field.

With the continuous development of laser communication technology, UAV-based laser communication ATP system is gradually developing towards lightweight and miniaturization. This paper presents a multiplex system based on fourquadrant detector, which integrates tracking and communication. By using a four quadrant detector, the precision tracking detector and communication detector in conventional laser communication systems are combined into one. This can reduce the weight, size and power consumption of the fiber optic terminal. The receiving unit uses the diversity receiving and merging function of the four quadrant detector to improve the signal-to-noise ratio and improve the communication performance.

With the rise and development of microelectronics as well as the optoelectronics industry, micro photoelectric devices, like miniature cameras, pose a serious threat to the privacy and security of personal and public information. To be able to quickly and accurately detect micro photoelectric devices, this paper, which is based on the previous theoretical research of our group, designs and builds a portable detection system for micro photoelectric devices from three aspects: system design, hardware selection and software design. In the actual test, the detection time of our system meets the real-time requirements, and the detection accuracy reaches more than 90%.

Infrared division-of-time (DoT) polarization imaging is a common polarization imaging mode, and it is usually necessary to use an infrared polarized radiation source composed of a blackbody and a polarizer to provide polarized radiation incidence and realize system calibration. The traditional visible-light polarized radiation source only needs to consider the energy attenuation caused by the transmittance of polarizer, that is, the emitted radiation is completely polarized radiation. However, in the thermal infrared band, it is necessary to consider the nonpolarized spontaneous radiation and polarized reflected radiation of the polarizer, which will bias the ideal polarized radiation estimation and affect the calibration accuracy of the infrared DoT polarization imaging system. In this paper, the influence of non-ideal infrared polarized radiation source composed of blackbody and polarizer on the calibration of infrared DoT polarization imaging system is studied, and a calibration model of infrared DoT polarization imaging system is proposed. The experimental results show that the modified model can improve the calibration accuracy of key parameters of the system, restrain the over-calibration, and obtain stable polarization imaging effect.

The detection of microplastics based on the principle of laser-induced fluorescence (LIF) is a promising technique for in situ detection of microplastics, however, the convenient and sensitive detection of the weak fluorescence signals of microplastics is a problem that needs to be solved urgently. In this paper, based on the TracePro software, the fluorescence intensity of microplastic particles with different particle sizes received by the detector under two irradiation methods is theoretically simulated and experimentally verified. The results show that under the same conditions, the fluorescence intensity detected by the oblique fluorescence detection system is larger than that of the orthogonal fluorescence detection system, and thus a kind of oblique fluorescence detection system for microplastics is proposed.

Under the dual carbon target, the development of offshore wind power has been vigorously promoted. In order to save costs, there will be a large number of land-based converter stations jointly built by multiple owners to concentrate the transmission of offshore wind power in the future. Different from the situation of a single owner, when multiple owners jointly build, the construction cost, construction period, electricity cost, electricity price, etc. of the station electricity system of the onshore converter station need to be reasonably shared. In response to this characteristic, this paper analyzes the four topological structures from four aspects: reliability, initial investment, measurement difficulty and applicable scenarios, and puts forward the technical and economic evaluation results of each scheme. When one or more transformers are installed in each unit, it is recommended to use a station power topology structure of a single 500kV station transformer+single unit connection or two station transformers per unit.

Doppler frequency shift, laser linewidth, phase noise and other interference in inter-satellite coherent laser communication pose new challenges to system carrier recovery. In this paper, a new optical phase-locked loop based on the loose tail phase discrimination method is applied to the QPSK homodyne coherent receiving system, and its modeling analysis is carried out. The optical phase-locked loop can achieve carrier recovery, which meets the high accuracy requirements of QPSK modulation for frequency and phase. The simulation analysis shows that the optical phase-locked loop can track the frequency offset of 10MHz/s, and can still work normally when the signal optical power is -50dBm, which is 5dB higher than the classical Costas optical phase-locked loop. It is one of the solutions for carrier recovery in coherent laser communication receiving system under QPSK modulation system, and provides a reference for coherent demodulation verification of QPSK homodyne coherent laser communication system.

Range-gated technique is useful for improving the accuracy of 3D target attitude measurements. The 3D super-resolution range-gated imaging technique and 3D inversion algorithm are introduced. In this paper, the characteristics of high-speed moving targets are analyzed. Nanosecond sensor gate is selected to capture instantaneous images to eliminate the effect of target movement. Based on this design, a dual-camera range-gated imaging measurement system is analyzed. Through imaging experiments on different targets, the system is feasible and for a target 20m away, the root-mean-square error of the measurement is 0.69cm. At the same time, the possible errors caused by the introduction of dual camera system and a reasonable solution is analyzed. The results show that the proposed system can effectively measure the 3D attitude information of high-speed moving targets, improve the ranging accuracy, meet the requirements of real-time 3D imaging, and provide a basis for subsequent data processing and ranging performance improvement.

Doppler wind lidar has gradually replaced traditional meteorological masts with its advantages of high precision and long-range detection, becoming the main method of wind field measurement. In this paper, the observation research was conducted in Zhangbei test site to test the dual-lidar virtual mast method through the combination of two wind lidars for synchronous scanning. On the basis of achieving pointing calibration and time synchronization, the dual-lidar system is used to measure the horizontal wind speed and wind direction at a height of 136 m of the mast. An environmental sensitivity error analysis is also carried out for 1-second wind speed data. The results show that the highly-synchronous dual-lidar system has the ability of replacing the met mast. By comparing with the wind speed of the 136 m cup anemometer in the mast, the mean deviation between the 10-minute and 1-second wind speeds of the dual-lidar system is within -0.04m/s, and the goodness of fit exceeds 0.98. In terms of error, turbulence intensity, wind veer, and flow inclination angle are significant environmental factors that cause second level wind speed errors, resulting in a total uncertainty of 1.9%.

With the aid of the particle swarm optimization algorithm (PSOA), the layout of 10x10 vertical cavity surface emitting laser (VCSEL) array is optimized to improve the output optical power. The simulation results show that, for the optimized VCSEL array with PSOA, the peak junction temperature is lowered by 6.55K, and the non-uniformity of the junction temperature distribution is improved by 32.56% when compared with the conventional VCSEL array without PSOA. As a result, the output optical power is increased by 89.86%. Furthermore, both the VCSEL arrays with and without PSOA are fabricated and the experimental results are consistent well with the simulation results.

The infrared imaging system represents the culmination of modern science and technology, finding extensive applications in aerospace, weapon electronics, security, industrial testing, and other fields. Target detection probability is a crucial parameter for evaluating the performance of an infrared imaging system and is closely linked to its design. While the Johnson criterion considers minimum resolvable temperature difference (MTRD) to assess the performance of infrared imaging systems, there exists an issue regarding low accuracy when applying infrared focal plane array (FPA) detectors. This paper proposes utilizing the targeting task performance (TTP) metric, that incorporates system sensitivity by considering a partial weighted integral of target background contrast exceeding the system contrast threshold function as a measure of information quantity within the system for simulating target detection performance in an infrared photoelectric system. In this study, we selected an uncooled infrared FPA detector and employed night vision integrated performance model (NV-IPM) software, along with control variable analysis to investigate how changing various system parameters affects the imaging performance of our proposed infrared photoelectric system. The purpose of this study to provide fundamental parameters for infrared imaging system optimizing future designs before research and development.

Due to the complexity of Micro-Electro-Mechanical System (MEMS) devices, errors are inevitable in the data capture process, and calibration using traditional methods encounters several challenges. Due to the geometrical characteristics of target satellites, which are generally polyhedral, a plane-based ranging error compensation method is used to achieve error correction of point cloud coordinates. The paper proposes a point cloud measurement error prediction model based on random forest, which is applied to the calibration of MEMS LiDAR point cloud data, and the analysis of the actual experimental data shows that the method can effectively improve the quality of the point cloud data, which verifies the effectiveness and feasibility of the proposed method.

Metasurfaces, as artificial structures capable of precise manipulation of optical wavefronts, demonstrate immense potential in the fields of optoelectronics and wireless communications. However, traditional design methods for metasurfaces often rely on intuition and trial-and-error, which are not only inefficient but also struggle to meet complex design requirements. The rise of deep learning technologies in recent years has offered a new perspective for addressing this issue. This study designs and improves a novel deep convolutional network architecture that integrates Wasserstein GANs and attention mechanisms for the efficient inverse design of metasurface structures. After testing on internal and external test sets and random spectra, the attention-based WGAN network model achieved an image accuracy of 0.98 and a spectral accuracy of 0.97, proving its efficiency and accuracy in designing elliptical metasurface structures.

In the dual-phase grating system of X-ray phase-contrast imaging, the reduction in structural requirements for the absorption grating relaxes the constraints on its aspect ratio and period, thereby broadening the applicability of X-ray phase-contrast imaging techniques in a wider market. Traditionally, the extraction of phase-contrast information primarily relies on phase-stepping methods or Fourier transform algorithms, which often introduce artifacts and blurring into the images. To achieve higher quality image restoration, this study introduces generative adversarial networks (GANs) for high-quality image reconstruction. Our approach uses ideal images as labels and images containing object stripe information as inputs, utilizing GANs for feature learning to facilitate the transformation from object stripe images to high-quality phase-contrast images. The network also employs transfer learning to process previously unseen object stripe images and generate corresponding phase-contrast images. This technique not only significantly enhances image resolution but also substantially reduces artifacts and blurring in the image processing, paving the way for high-precision demands in medical diagnostics and industrial inspection.

The three-wavelength demodulation method plays a significant role in high-speed fiber Fabry-Perot sensing signal processing. It has been applied to demodulate extrinsic Fabry-Perot interferometric interference signals with low-fineness. However, there will be significant errors when it applied to high-finesse Fabry-Perot signals formed by high reflectivity. To address this issue, this paper proposes a three-wavelength arctangent phase demodulation method specifically for high-finesse Fabry-Perot interference signals. By transforming the multi-beam interference signal, the method satisfies the cosine model, enabling high-precision demodulation of optical path variation. Further experiments were conducted on thin-film Fabry-Perot signals at different temperatures, and the results demonstrate that the proposed improved three-wavelength demodulation method achieves a measurement error of less than 6 nm

The reflective optical system is widely used in the military and civilian fields. Satisfactory assembly is the premise to ensure the performance of the optical system, and the identification of misalignment errors is the pivotal step of assembly. In this paper, the neural network was used to identify the non-ideal misalignment errors in the assembly process. The wave aberration was studied and the assembly model of a two-mirror reflective optical system was established. The misalignment errors of the secondary mirror were randomly generated and combined, and the corresponding Zernike coefficients were obtained through simulation. The misalignment errors identification model of neural network was established. And finally, the validity of this model was verified. The method proposed in this paper can achieve efficient and accurate identification of misalignment errors, which is of great significance for improving assembly efficiency and accuracy.

Background estimation and motion target detection under moving platform are key technologies in motion camera system, which has attracted much attention in recent years and is widely used in security monitoring, UAV detection and other optoelectronic detection systems. When the camera is mounted on a moving platform, the movement of the platform causes a corresponding displacement of the image background captured by the camera. Therefore, the stationary background estimation method based on a stationary camera is no longer applicable in this case. In this paper, we propose a method for calculating the image motion information using the dynamic template phase matching method. Homologous signal trajectories are then established based on the image motion information to compensate for the inverse motion of the background image. Finally, a more accurate stationary background image is obtained using the background modeling method.

Poor stability of spectral signals has been a key issue limiting the development of laser-induced breakdown spectroscopy (LIBS) technology. Unlike traditional LIBS where the sample is punctured at the focal point, this study proposes a method using an out-of-focus large spot to excite the sample. A Cu-Zn alloy target was selected as the experimental object, and the obtained spectra were pre-processed. By calculating the relative standard deviation (RSD) and signal-to-background ratio (SBR) of the spectra for Cu (514.325 nm) and Zn (468.010 nm) elements in the Cu-Zn alloy target, it was found that as the sample moved back and forth along the optical axis with the laser focal point as the center, the spot became larger and the spectral signals became more stable. The RSD showed a tendency of decreasing and then increasing, while the SBR showed a tendency of increasing and then decreasing. At a distance of 2-3mm from the focal point, the spot size became about 2 times the focal point, and the RSD was the lowest at this point. The RSD of the spectral signal for the Zn (468.010 nm) element in the pre-focal area decreased to 1.5%, which was 1/12 of that at the focal point, while the RSD of the Cu (514.325 nm) element decreases to 0.6%. Mathematically, the 2-3mm range from the focus represented the inflection point of energy density change and had the highest electron density and lowest electron temperature, resulting in the best stability. Compared with other methods to improve the spectral stability of LIBS, the proposed method of outof-focus large spot excitation is simple, convenient, easy to operate, and has good practical value for wider application and dissemination.

This article focuses on the photovoltaic power generation system at expressway toll stations as the research object. Firstly, the necessity and significance of the layout of the photovoltaic power generation system at expressway toll stations are discussed from the perspectives of power generation efficiency, operation cost, energy consumption, and business promotion. Subsequently, the structure, working principle, and functions of each power-consuming unit of the photovoltaic power generation system at toll stations are introduced in detail. The three working states of the photovoltaic power generation system are analyzed, providing theoretical basis and technical foundation for the application of photovoltaic toll stations on expressways, which is conducive to promoting the green development and construction of expressways and has certain practical value.

Evaluating the uncertainty of a hyperspectral color measurement system is the best method to assess the accuracy of its chromaticity measurement results. Based on the analysis of uncertainty evaluation methods for measurements, combined with the characteristics of color measurement, the uncertainty of measurement results is evaluated. Firstly, the methods for calculating luminance and chromaticity uncertainties are analyzed according to the "Guide to the Expression of Uncertainty in Measurement" and CIE chromaticity calculation formulas. Then, by analyzing the influence of various factors during the measurement process on chromaticity measurement, the uncertainty of spectral reflectance is obtained. Subsequently, based on the uncertainty of spectral reflectance, the uncertainties of luminance and chromaticity are calculated. Finally, the cross-validation results with the standard reference instrument CM-700d demonstrate the feasibility of the uncertainty evaluation method for color measurement results, laying a theoretical foundation for further research.

In recent years, China is the world's largest PV producer, the most complete PV industry chain, the largest PV market and the largest PV power generation capacity. Under the dual-carbon target, the future development trend of China's PV market is very important. Based on the sample data of China's annual cumulative PV installations from 2001 to 2022, its regression equations were obtained by MATLAB software using cubic polynomials, exponential curves, Peel's growth curves, linderuo's growth curves, quadratic exponential smoothing, and BP neural network training models, respectively. After comprehensive analysis, the cubic polynomial curve and exponential curve fitting are better in terms of continuity, growth, reliability and rapidity, but the exponential method accelerates the error with the increase of extrapolation year, so it is recommended to use the cubic polynomial curve. Finally, the cubic polynomial is used to forecast the annual cumulative installed capacity of PV (including distributed and centralized) in China from 2023 to 2030. Comparing with the results predicted by the China Photovoltaic Industry Association (CPIA), the prediction results of this paper are on the small side, which is mainly due to the neglect of the effects of favorable policies, technological breakthroughs, and increasing domestic and foreign market demand

Energy conservation and emissions reduction are at the forefront of China's economic development agenda due to the country's rising energy demand. The paper examines the energy economy system of Heilongjiang Province, China, with a focus on governments and businesses as research subjects. Using game theory, a hybrid strategy game model between the government and energy companies is constructed to analyze a variety of factors, including government inspection costs, short-term profits of energy companies, and incentive levels. The findings of the study indicate that collusion between local governments and businesses can be effectively curbed by implementing measures such as cost reduction and increased government penalties. Governments should establish a robust and effective energy economy development system, which would facilitate the coordination of relationships among different entities within the energy economy system, with the aim of improving enterprise efficiency in the implementation of national low-carbon economic policies.

When a small hole leakage occurs in the natural gas pipeline, it is difficult to be detected. To detect small hole leaks in natural gas pipelines more quickly, effective inspections need to be conducted on the natural gas pipeline. Therefore, this paper proposes a deep learning detection method based on a distributed feedback fiber laser (DFB-FL) vibration sensor, known as NL-Net. The DFB-FL vibration sensor has high strain resolution and is highly sensitive to acoustic signals, making it suitable for capturing pipeline leak signals. NL-Net consists of multiple local feature extraction blocks (LFLBs), which can deeply analyze the features in the signal and classify leaks of different sizes. Experimental results demonstrate that NL-Net achieves a classification accuracy of up to 97.4% for different leak sizes, with a testing response time of only around 10ms and rapid convergence. The combination of NL-Net with the DFB-FL vibration sensor-based natural gas pipeline leak system enhances its practical applicability, contributing to the development of a more efficient and reliable natural gas pipeline infrastructure. This integration offers effective analytical algorithm support for future research endeavors focused on improving the safety and efficiency of natural gas pipeline systems.

Camera-LiDAR joint calibration is the basic requirement for data fusion of two sensors in autonomous vehicle. In order to minimize the re-projection error of the joint calibration and enhance the accuracy of the fusion of image and laser point cloud data, a Levenberg-Marquardt algorithm is designed to optimize the external parameters for the joint calibration of the camera and LiDAR. Firstly, the least square function is constructed based on the difference between image pixel coordinates and point cloud re-projection coordinates. To reduce the number of optimization parameters, we employ the Rodriges transformation, a formula that enables us to represent the rotation matrix using a vector of only 3 parameters. Then, the Levenberg-Marquardt algorithm is utilized to optimize the joint calibration parameters and solve the optimized re-projection error. The results demonstrate that the optimized re-projection error is 0.226, which is reduced by 53.5% compared with before optimization, and the accuracy of joint calibration is improved. Finally, visualization of the calibration results validates the effectiveness of the optimization algorithm.

Optical communication technology is the future direction for realizing high-speed broadband networks in space. However, the performance of optical communication will be limited by atmospheric turbulence in the pathway. Adaptive optics have been proved effective in suppressing atmospheric turbulence, but adaptive optics have reduced efficacy in strong atmospheric turbulence due to light intensity scintillation. When light intensity scintillates, current wavefront recovery algorithms will have reduced spatial resolution and poor wavefront recovery accuracy. In this paper, a novel wavefront recovery algorithm is proposed to set up a light gatherer for every sub-aperture of the Schack-Hartmann wavefront sensor influenced by light intensity scintillation. Distributed light gatherer is set for every sub-aperture with insufficient light intensity, and gatherer will keep ADU accumulation until the set accuracy threshold is satisfied. Then, use mode method to get the distribution of aberration phase. This reconstruction algorithm is numerically simulated and experimentally verified under the condition of light intensity scintillation. The results show that, when the atmospheric turbulence has a scintillation factor of 0.50, the recovered wavefront processed by the distributed light gathering method is significantly improved compared with the results of the conventional recovery algorithm: the wavefront recovery error is reduced from 1.34λ to 0.82λ, which is 0.52λ less, and the accuracy effect is improved by 39%. The proposed algorithm can effectively enhance the accuracy of center-of-mass computation under the light intensity scintillation condition caused by atmospheric turbulence and improve the performance of adaptive optics system.

Considering basic scenarios like electrochemical energy storage configuration projects, hydrogen production configuration projects and more, this study establishes a general framework for the life-cycle economic analysis of offshore wind power projects against the background of new power system construction. This framework overcomes the incompleteness of the previous economic analyses of offshore wind power projects by ignoring energy storage and other supporting facilities. Additionally, considering the perspectives of project investment and capital base, a life-cycle economic quantitative model of offshore wind power projects for the aforementioned three scenarios is established. A case application is produced to calculate the key indicators for the offshore wind power project under the three scenarios. The results show that the net present values (NPVs) are all negative across all three scenarios, indicating that the current offshore wind power does not have the conditions to achieve grid parity without external support. On this basis, this study further calculates the financially feasible minimum on-grid electricity price of the project and screens out the key factors affecting the on-grid parity of offshore wind power grids. It is found that the issue of offshore wind power parity requires supporting facilities and cost reduction.

The streak tube with a large effective photocathode area, high spatial resolution, and high temporal resolution are essential for improving the detection accuracy of the streak tube imaging lidar (STIL). In this paper, a three-dimensional streak tube with single-lens focusing system is developed in CST STUDIO SUITE to systematically investigate the dependences of the dynamic spatio-temporal resolution on the geomagnetic fields. The electro-magnetic distribution in streak tube is calculated by adopting discretized Maxwell’s equations and Finite integral method (FIM). Monte Carlo (M-C) sampling is used to determine the initial distribution of electrons in the visible photocathode. The photoelectrons trajectories are tracked by using the particle-in-cell (PIC) method. All simulations are conducted under both shield (no magnetic field applied with the 3D model) and unshielded (49524.5 nT magnetic field applied with the 3D model) conditions. The results show that the shielding structure can significantly reduce the spatial dispersion of streak tube, and greatly improve the spatial resolution. In addition, there is little difference in temporal resolution, with or without a shielded structure.

In the context of the “dual-carbon” strategy, the integration of renewable energy with agriculture has emerged as a novel approach, offering a new model to address land tension during urbanization, enhance the efficiency of utilizing urban idle spaces, and foster sustainable green urban development. This paper introduces the design of a rooftop greenhouse system based on renewable energy and the Internet of Things (IoT), built upon the study of photovoltaic power generation and rooftop greenhouses. Initially, we propose a feasible solution for rooftop greenhouse space agriculture and construct an architectural model to optimize the layout of photovoltaic arrays. Subsequently, we design a greenhouse remote monitoring system with STM32 as the control core, employing LoRa modules for information transmission from the collection terminal and enabling remote interaction with the upper computer through the NB-IoT module. Next, we introduce an improved APSO-optimized fuzzy PID algorithm (APSO-FUZZY-PID) and compare its control effects with two other temperature control models. The results demonstrate that the APSO-FUZZY-PID control model achieves higher efficiency and accuracy. Finally, the optimized GWO-BP neural network is employed to forecast the photovoltaic greenhouse temperature. Our MATLAB simulation analysis reveals that the GWO-BP prediction method exhibits higher accuracy compared to traditional prediction methods.

Zoom optical systems are versatile, serving applications from daily life, including photography, monitoring, and microscopy, to aerospace and national defense construction. With increasing applications, their performance standards are escalating. This paper introduces a 50mm-150mm three-configuration continuous zoom optical system. Employing a positive compensation structure, it achieves optical zoom in the visible band (390nm-760nm). Composed of six spherical glass lenses, it boasts a compact design with a total length of 40mm and a max aperture of 66mm, ensuring an F-number superior to 5 at long focal lengths. This system meets miniaturization demands while maintaining a high MTF (>0.32) across the entire field of view in the visible light band. The design fulfills high-performance criteria and offers valuable insights for the design of visible-band zoom optical systems with high magnification ratios and miniaturized footprints.