This paper describes recent results from the Extremely High Temperature Photonic Crystal
System Technology (XTEMPS) technology program. The XTEMPS program has developed a
Photonic Crystal (PhC) based high efficiency IR emitter array for use in the emerging generation
of wide field of view high performance scene projectors. Cyan's approach provides high
dynamic range, multispectral emission from SWIR to LWIR and is uniquely capable of
accurately simulating very realistic system spectral signatures. The PhC array is fabricated from
refractory materials to provide high radiance and long service lifetime. Cyan is teamed with
Sandia National Laboratories for design and fabrication of the emitter and with Nova sensors to
utilize their advanced Read In Integrated Circuit (RIIC). PhC based emitters show improved inband
output power efficiency when compared to broad band "graybody" emitters due to the
absence of out-of-band emission. Less electrical power is required to achieve high operating
temperature, and non-Lambertian emission pattern puts a large fraction of the emitted energy
into a straight ahead beam. Both effects significantly boost effective radiance output. Cyan has
demonstrated pixel designs compatible with Nova's medium format RIIC, which ensures high
apparent output temperatures with modest drive currents and low operating voltages of less than
five volts. Unit cell pixel structures for high radiative efficiency have been demonstrated and
arrays using PhC optimized for up to four spectral bands have been successfully patterned and
fabricated into high yield wafers.
Recent advancements in gallium antimonide light emitting diode (LED) arrays have opened the way for the
development of LED-based infrared scene projectors. Infrared LED array technology offers the opportunity for
high frame rates, broad dynamic range, and high apparent temperatures. Since LEDs are narrow-band devices,
relative to blackbody emitters, performance of an LED-based infrared scene projector is highly dependent on how
effective and apparent temperatures are calculated in a detector system being tested. Because of this dependence,
methods used to compute effective and apparent temperatures are reviewed and applied to published radiometric
data from a gallium antimonide LED array. These calculations are used to investigate the effects of detector
spectral response, emitter array fill factor, emitter radiant flux distribution, and detector aperture size on the
apparent temperature of the LED array. This investigation leads into an analysis of the potential performance
advantages and technical challenges of an LED-based infrared scene projector system.
This paper describes results from the Extremely High Temperature Photonic Crystal System
Technology (XTEMPS) program. The XTEMPS program is developing projector technology
based on photonic crystals capable of high dynamic range, multispectral emission from SWIR to
LWIR, and realistic band widths. These Photonics Crystals (PhC) are fabricated from refractory
materials to provide high radiance and long device lifetime. Cyan is teamed with Sandia
National Laboratories, to develop photonics crystals designed for realistic scene projection
systems and Nova sensors to utilize their advanced Read In Integrated Circuit (RIIC). PhC based
emitters show improved in-band output power efficiency when compared to broad band
"graybody" emitters due to the absence of out-of-band emission. Less electrical power is
required to achieve high operating temperature, and the potential for nonequilibrium pumping
exists. Both effects boost effective radiance output. Cyan has demonstrated pixel designs
compatible with Nova's medium format RIIC, ensuring high apparent output temperatures,
modest drive currents, and low operating voltages of less than five volts. Unit cell pixel
structures with high radiative efficiency have been demonstrated, and arrays using PhC
optimized for up to four spectral bands have been successfully patterned.
High performance LWIR and VLWIR focal plane arrays have been produced on advanced HgCdTe/ZnCdTe materials. The ZnCdTe substrates typically are n-type with an infrared transmission over 65%. Mesa and planar ion-implantation-isolated heterojunction processes have been used to produce the arrays. The operability of 128x128, 10.6mm arrays reached 99.27% based on the criteria that the signal output is within +/-30% of the mean. Several 320x256 arrays with wavelength from 12mm to 13.75mm at 77-85K have also been produced. Excellent imaging pictures have been obtained at these temperatures.
Spectral radiometers and imaging radiometers have been used for decades to provide detailed information about the infrared properties of remote objects. Both of these senors provide complementary information. Even more information can be obtained using a fusion of these two instruments. A spectral imaging radiometer provides data absolutely registered in the spatial, spectral and temporal domain. In this paper we present SARIS, a new spectral imaging radiometer that will operate both from airborne and ground-based platform. SARIS will provide high speed, highly accurate, 16 X 16 spatial radiometric measurements with 1 cm-1 spectral resolution in the 2 to 5 micrometer spectral band. SARIS will measure up to 150 datacubes (a datacube is a complete spatial/spectral measurement) at a spectral resolution of 8 cm-1 and covering the spectral range from 3.5 to 5 micrometer. In this paper we present the mission, technical requirements and conceptual design of SARIS.
The Department of Defense, through the US Air Force's Wright Laboratory, Armament Directorate is sponsoring the development of two types of IR imaging spectroradiometers (project name: IRIS) to measure the spatial/spectral characteristics of various military targets. Design and analysis of several technical approaches were conducted during an initial phase of the program. The technical approaches investigated included: a dispersive imaging spectrometer design utilizing a fiber-optic reformatter (contractor: ERIM); an imaging acousto-optic tunable filter (AOTF) design (contractor: Westinghouse); a spatial/spectral Fourier transform infrared (FTIR) spectrometer (contractor: Bomem Inc./Canada); a spatially modulated imaging fourier transform spectrometer (contractor: Daedalus Enterprises); an imaging Fabry-Perot design (contractor: Physical Sciences Inc.). Two of these designs were selected for brass board prototype fabrication. An FTIR prototype being built by Bomem Inc., offers an instrument with high sensitivity and high spectral resolution with modest spatial performance. An imaging Fabry-Perot prototype being built by Physical Sciences Inc., offers high spatial resolution with moderate sensitivity and spectral resolution.
A Scophony Infrared Scene Projector (IRSP) is being used at Wright Laboratories Armament Directorate, Guided Interceptor Technology Branch, Eglin AFB, to evaluate thermal-imaging guidance systems. This hardware-in-the-loop testing system reduces the number of necessary field trials and has potential for in-laboratory simulation where the performance of entire seeker systems can be analyzed. The performance of an optical system, in terms of such characteristics as wavefront error, resolution, and transfer factor, can be measured with knowledge of the system MTF and PSF performance. A slow-scan calibration system was used to measure an image plane of the IRSP under three separate configurations of the system. MTFs and PSFs were derived for the IRSP without the use of the scatter screen, with the scatter screen in place, and with the scatter screen rotating.
Silver gallium selenide (AgGaSei) crystal for efficient second-harmonic-generation of C02 laser lines has been demonstrated using a pulsed laser. However, the use of this crystal in continuous wave (CW) lasers is limited due to its low laser damage threshold. In this paper, laser damage threshold measurements obtained using a 9 µm C02 laser will be discussed. The data obtained for the frequency doubling of 9 µm to 4.5 µm will be presented.
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