HgCdTe is a very important material for IR detector. The solid state recrystallization (SSR) is a very useful method to prepare HgCdTe single crystal. The defects in as-grown HgCdTe crystals grown by SSR method are introduced, the relationship between cause of resulting in these defects and crystal growth process is discussed simply in this paper. The research results have shown: if raw material purity is raised, stoichiometry is suitable and quench process is improved, the defects in HgCdTe crystals can be reduced and the quality of as-grown HgCdTe crystals can be improved.

A hybrid HgCdTe 128 X 4 FPA for LWIR detection was fabricated. HgCdTe epilayers were grown on GaAs substrates by MBE. The n⁺ on p photodiodes were formed by boron ion implantation. The detector array was passivated with a combination of CdTe and ZnS layers to provide a harmonious transit range between HgCdTe surface and passivation layers. And the combination layers of CdTe and ZnS present a low charge densities and very good electrical properties. The mean product of zero bias differential resistance and area for the diode array was measured to be 3 (Omega) -cm² with a cutoff wavelength of 10.05 micrometers . TDI CCD readout circuits designed and fabricated especially for this 128 X 4 LWIR FPA with charge capacity of 1 to 1.5 X 10⁷ electrons. This shows the characteristics of HgCdTe detector array of the epilayers grown by MBE on GaAs substrates, and also indicates than n⁺ p junction formation process and the surface passivation procedure are useful in the fabrication of HgCdTe FPAs.

The recent progress in MBE growth of HgCdTe at the Epitaxy Research Center for Advanced Materials, and the National Laboratory for Infrared Physics is described. It was found that the surface morphology is sensitive to the growth temperature and the flux ratio. The compositional reproducibility studied in a limited number of samples showed that a STDDEV for x-values of 0.0017 deviated from an average value of 0.229 was obtained. The epilayers showed excellent compositional uniformity across 2-inch wafers, the relative deviations for x-value and thickness were found to be 0.18 percent and 2.19 percent respectively. Ellipsometer was used for real-time monitoring the compositional variations during growth. The post growth annealing process was found to be effective in reducing the dislocation density, a reduction in dislocation density by approximately 50 percent could be obtained even by approximately 250 degrees C low temperature annealing. Electrical properties of epilayers are described, and a p-type in situ vacuum annealing process was demonstrated. MBE grown p-HgCdTe epilayers were successfully incorporated into 32 X 32 focal plane arrays detectors.

We measured refractive index of n type Hg_1-xCd_xTe with the null ellipsometric spectrum method over the visible light region, and the dispersion spectra with compositions x ranging from 0.2 to 0.46 have been obtained at different temperatures. The reflectivity has been calculated in the wavelength region above the absorption edge at temperatures from 77K to 300K. A peak over the visible light region appears just at the wavelength corresponding to the band-gap energy E₁(x,T) of Hg_1-xCd_xTe. E₁(x,T) can be described by an empirical formula.

This paper briefly presents the recent development of IR physics and photo-electronic device, the HgCdTe detector is successfully used in the scanning radiometer on the meteorological satellites. As an important developing direction for the photo-electronic device, the low dimensional semiconductor structures are investigated. The interface intermixing technique has been developed to modify the energy band structure of multi-quantum wells and consequently response wavelength of the quantum well IR photoconductive detector. The quantum wires have been successfully grown and demonstrate good optical properties.

Cd_1-yZn_yTe (CZT) wafers with (111) orientations, which serve as the common substrates for Hg_1-xCd_xTe (MCT) epitaxial deposition, were treated with different processes of mechanical polishing and chemical etching and then tested by x-ray diffraction unit with the same experimental conditions. The conclusion is that the sample surface treatment dramatically influences the values of DCRC FWHM. The most desirable process and its experimental conditions for accurate measurement of DCRC FWHM have also been reported in this paper.

The development and figure of merit of photoconductive HgCdTe multielement detector used in multi-spectral scanner in thermal IR band are reported in this paper. It focuses on the method of resolving the non-uniformity of spectral response curve for multielement device. The testing and scaling methods on the responsivity R_(Delta (lambda) 1) of figure of merit waveband, the detectivity R*_(Delta (lambda) 1) of waveband and the responsivity R_(lambda ) of monochromatic waveband are also discussed briefly, as well as the situation of aging test and environmental test under space environment condition. The test result shows that the technical index of the multielement device can meet the requirements of space multispectral scanner and its performance is stable and reliable.

A new method of studying the deep levels in Hg_1-xCd_xTe was proposed. Through analyzing the relation between mobility and temperature and that between carrier concentration and temperature, we obtained some important information about deep levels. First, the Fermi level was calculated from the measured electron concentration by using the Kane's band model. Then the hole concentration was obtained from this Fermi level. Compared with the electron concentration calculated by the electrical neutrality equation, the measured one had the contribution from the deep level at the temperature range of about 200K. The electron mobility was also theoretically calculated. Deep level's contribution to the measured electron mobility was also discussed. Finally, a two levels model, and a fitting method as well, was proposed.

HgCdTe (MCT) 256 X 4 TDI long wave IRFPA and SPRITE are both preferable devices of high performance IR imaging systems. As we know, IRFPA is better than 60, 120-element long wave photoconductive detectors. But the comparison between 256 X 4 TDI IRFPA and 8 X 4 sprite has never been discussed. This paper is focused on the comparison between the output SNR of the two detectors because they have different spectrum response. Generally speaking, a 8 X 1 sprite is only equal to 100-element photoconductive detector. But the results of our research show that 8 X 4 sprite detector can function similarly to 256 X 4 TDI IRFPA when applied in IR imaging systems whose object is in ambient temperature.

The transmission spectra and response spectra were measured in the same small region of Hg_1-xCd_xTe material over a temperature range 85K < T < 300K. The relationship between the cut-on wavenumber of the transmission spectra and the cut-off wavenumber of response spectra in the same temperature is shown and the empirical expression is deduced as following: v_cutoff equals 2.407 X 10^-2 + 1.401v_cuton - 1.199v_cuton².

Planar n⁺-on-p SWIR Hg_1-xCd_xTe(x equals 0.577 approximately 0.669) photodiodes passivated with ZnS were irradiated by Co⁶⁰ gamma source. The room temperature current-voltage characteristics of the photodiodes were carried out following the irradiation. And response spectrum, capacitance-voltage and noise spectrum of the devices were measured respectively before and after 1.0Mrads gamma irradiation. The results are found that the RT SWIR HgCdTe photodiodes are extremely hard to gamma irradiation with no perceivable deterioration in the device performance even upon irradiation of up to 1.0Mrads.

The low temperature current gain and the low frequency noise are important parameters of the preamplifiers of the integrated IR receiver system. Si/Si_1-xGe_x heterojunction bipolar transistors (HBTs) have potential advantages used in the preamplifiers at low temperature. In this paper, we analyze the characteristics of the current gain and low frequency noise of Si/Si_1-xGe_xHBTs at low temperature. They are influenced by the following factors: (1) the energy band offset of the emitter-base junction; (2) the high doping effect, the low temperature freeze out effect in the emitter region and base region; (3) the influence of germanium (Ge) content and profile in the base region on the transport performance; (4) the Si/Si_1-xGe_x interface recombination currents and surface recombination currents; (5) the collector-base heterojunction barrier effect. Then we give the physical analysis model and noise analysis model of Si/Si_1-xGe_xHBTs at low temperature. Based on this, we present the equivalent circuit and equivalent noise circuit at low temperature and simulate and optimize the characteristics of the current gain and the noise of Si/Si_1-xGe_x HBT for IR integrated receiver system. The current gain (beta) max equals 300, and the low temperature current gain (beta) max equals 8100 at 77K, at high injection level. We optimize the design of Si/SiGe HBT-based monolithically integrated preamplifier applied to IR receiver system at low temperature.

A relation equation of the best multiplication factor for APD photoelectronic detector is derived, a temperature compensation method of C30950E and its relative circuits are designed in this paper.

Diffractive microlens arrays have been designed to improve the performance of PtSi Schottky barrier IR image sensors. They have been fabricated on the surface of Si substrates by successive photolithography and Ar⁺ ion-beam-etching technique, which operate at (lambda) equals 4.0 micrometers with a lens diameter of 100 micrometers and the lens F number of 1.56. The practical processes and fabrication method are shown and discussed. The microanalysis and optical characteristics of the diffractive microlens arrays are also presented. The experimental and theoretical results are in good agreement.

In this paper, the compatibility of P⁺-Ge_xSi_1-x/p-Si heterojunction internal photoemission IR detector (HIP IRD) with its CMOS readout circuit is analyzed with a feasible approach presented. The experimental chip in which P⁺-Ge_xSi_1-x/p-Si HIP IRD and its NMOS readout switch are monolithically integrated has been fabricated with a 3 micrometers NMOS technology. The MBE grown detector without the dielectric cavity and anti-reflecting layer has a blackbody detectivity D*_{(500, 1000, 1}) of 1.1 X 10⁹cmHz^1/2/W at the temperature of 77K. The selective readout of the output signals of the detectors through the NMOS readout switch at 77K has been achieved. Therefore, the feasibility of fabricating monolithically integrated P⁺-Ge_xSi_1-x/p-Si HIP IR focal plane array with NMOS readout circuit was demonstrated preliminarily.

In this paper, the theoretical analysis of the quantum efficiency in an n⁺-p GaInAsSb IR photovoltaic detector is presented. The investigations of material parameters and the direction of the incident light are carried out for the near room temperature and 2.5 micrometers wavelength. The analysis results show that the direction of the incident light effects on the quantum efficiency. In addition, the quantum efficiency strongly depends on the carrier concentration in the p region. Moreover, other material parameters also effect on the quantum efficiency.

III-V antimonide compounds are of great interest for their applications, such as optical communication, environmental protection, remoting sensing of atmospheric and IR focal plane array for imaging. In this work, MOCVD growth and characterization of GaSb-rich and InAs-rich GaInAsSb quaternary alloy on GaSb substrate are investigated. The optimal growth temperature for InAs-rich GaInAsSb is a little lower than that for GaSb-rich films owing to the different melting points between these two kinds of epilayers. With the aspect of electrical property, there are two types of electrical conduction in the whole range of composition. InAs-rich GaInAsSb epilayers display n-type conduction while GaSb-rich films p-type. The origin of these two kinds of electrical conduction is believed to be related the intrinsic defects in the epilayers. A new structure of IR detector is proposed according to the different electrical conductions of GaInAsSb epilayers in the different range of composition. It is expected that the performance of the photodiode could be improved.

In this paper, the characteristics and applications of the window materials within the range of UV, cathode in near UV, and the analogue imaging system of the double-proximity type in near UV with the Au thin film cathodes were introduced.

The configuration of imaging photon-counting intensifier (IPCI) is introduced, and the differences between traditional II generation intensifiers and the IPCI are given. Based on the single channel photon-counting technique, the measurement principle and method of the IPCI's key performances, such as dark count and photon gain are discussed theoretically. The experimental system has been developed. Measurement work of the two performances mentioned above are carried out under the condition of different MCPs operating voltage and temperature. The experimental result and its comparison with traditional II generation intensifiers are presented.

A new type of filmed microchannel plate (MCP) is described which as been optimized for use in third generation image tubes. The glass structure is specially formulated for high temperature processing and superior electrical characteristics. The technique for preparing ion barrier film at the input of MCP has no effect on the electric performance of MCP.

Superconducting YBCO microbridge has been proven with high sensitivity and fast response speed. We have prepared successfully the High Tc superconducting IR detectors of this composition. When the temperature of blackbody is 500K the performance of detector is: D* equals 5.06 X 10¹⁰ cmHz^1/zW^-1; NEP equals 2.8 X 10^-14WHz^-1/2; R equals 8.87 X 10⁴VW^-1 and this performance can be held stable in two years. Using the detector we have done experiment at bolometric response from 300K to 600K and spectral response from 1 micrometers to 1224 micrometers . Experiment results show that the detector is nearing practical use and is the best detector for wide band.

According to the structure and work characteristic of the pyroelectric detector and on the basis of the performance evaluation technology of staring thermal imaging systems, the performance prediction technology for the pyroelectric array IR detector was developed and a software was presented in this paper, the performance model of this kind of detector is analyzed, some questions of this kind of detector are discussed and the software is introduced simply.

In this paper, an experimental research on the effect of the Miniature Stirling cooler on the noise of a photo-voltaic QD has been fulfilled. Based on strictly implements, the noise power spectrum densities of the QD under Stirling cooling have been measured and compared with that of Liquid N₂ cooling. The results showed that the Stirling Cooler will cause additional noise to the QD it cooled, but the increasing noise can be reduced if some means are taken.

The Langmuir-Blodgett (LB) films of hemocyanin dyes were prepared by LB technique. The films show pyroelectric effect. The pyroelectric coefficient measured by the method of integrated charges is 12 (mu) C m^-2 K^-1 at room temperature. The relationship between the orientation of DAEP in the films and temperature was studied by polarized FTIR spectroscopy and second-harmonic generation. The physical mechanism of pyroelectricity in the films was also discussed.

Based on the photon noise fluctuation theory linear filter theory the threshold specific characteristics and vision theories of the human eye, a new threshold detection theory and apparent distance detecting equation of LLL imaging system will be established and derived in this paper.

This paper presents a method for acquiring sine grating pattern of dynamic varying frequency using for measuring the modulation transfer function (MTF) of CCD. The measured results show that the spatial frequencies of grating patterns generated by this method can be continuously changed within the range of 0.2 to 80 lp/mm, the frequent of which is lower than 1 lp/mm. The modulation contrast of patterns is close to one. We have used them to measure the MTF of area array and linear CCD, and the result are satisfactory.

Sampling is a necessity in discrete imaging systems. In the event that the scene being sampled contains information with frequencies greater than half the sampling frequency, the resulting samples will contain aliasing error artifacts caused by spectral foldover of the periodic sampled image data. We analyze two models for the reduction of aliased signal energy in discrete imaging systems, microscan model and optical refiltering model. Microscan model means translating the image over the detector array by a subpixel distance and then resampling the image, thus increasing the spatial sampling rate to provide the discrete imaging system with a large aliasing-less bandwidth. Optical refiltering model means considering an optical prefilter which makes an image to have no frequencies greater than the Nyquist frequency, insuring that any aliasing information will not appear in the output image. Computer simulation is presented to compare these two models and relative merits of each of them are discussed. It is difficult to say which model is better due to their different schemes in dealing with the high frequencies. A performance tradeoff selection between microscan and refiltering must include the purposes, conditions and quality demands of the imaging process practically considered.

The recording of the hologram in the optical scanning holography (OSH) proposed by T.C. Poon is a process in which a Fresnel zone plate (FZP) is used to scan the object, but since the spacing between two adjacent rings of FZP at the center portion is greater than that at the edge portion, the resolution capability of the system, which can resolve the edge portion of the FZP, is not fully exploited. The fact that a circular grating (CG) has uniform spacings everywhere, enlightens us to suggest the CG optical scanning holography. It has been found that the optical transfer function of the system equals the Fourier transform of the intensity transmissivity of the projecting circular grating, and the point spread function of the system equals to a (delta) function. Also given in this paper are the principles of the CG optical scanning holography and the computer simulations.

The film model display device consists of the pyroelectric film, the liquid-crystal and information processing circuit. The device based on pyroelectric effect of ferroelectric material and electric-light effect of the liquid-crystal material. It can transform IR radiation into visible light. The paper derives relation of different parameters between various departments. With utilize relation to design and investigate the film model detection device, we study and made one cell, two cell and four cell display device. These are bases to study multi-cell image system.

In this paper, we described the experimental work on developing a demountable CCD-Digicon, an electron-bombarded charge-coupled devices detector, and give a description of a prototype tube and its technological process. One of our electrographic cameras that had been accomplished by ourselves years ago, can be used as a special processing chamber, to prepare photocathodes and achieve final indium seal of detector assembly in it.

The paper emphatically inquires into effective method that describes effects of smoke screen on thermal image. In order to accurately reflect and describe the impact of IR smoke screen on thermal image as far as possible, regarded as a kind of audio-visual scheme, visibility judgement of target is adopted. That is, statistical mean of discernible area of target in proportion to overall area of target is judged in the course of releasing smoke screen. Moreover, the data obtained is processed further and one kind of comprehensive evaluating method is given.

Under the condition of laying artificial smoke screen, studying transmission property of IR, laser and visible light, especially studying the effect of smoke screen on transmission of thermal image of target is of theoretical and practical significance. The paper is based on a field- testing during which artificial IR smoke screen was produced. In the course of testing, typical motor vehicle in operating condition was chosen as target. By combing the change of typical thermal image which was taken by AGEMA-880 thermovision before and after IR smoke screen producing with a large amount of data concerned, the nature and law are studied and analyzed that different types of IR smoke screen have an effect on thermal image of target and image quality of thermovision. Therefore, we further have put forward that the change of thermal image quality is reflected under the influence of smoke screen by fractal fitting error.

Since nonuniformity of IR imaging system seriously limits its working performances, we have done some research on measuring nonuniformity of RI image to improve its image quality. This article proposes a method in measuring nonuniformity of Group 1 IR Imaging System based on the practical measurement. By analyzing the result we can conclude that nonuniformity of Group 1 IR Imaging System limits its working performances at the level of about 5 percent.

This paper shows that the phase match between input signal and CCD pixel has influence on the measuring results of MTF by the analysis of the CCD sampling process. We have obtained the situation that MTF values of linear CCD change with the phase of input signal using the setup made by ourselves. The results accord with the theory results.

An adaptive optics system with the adaptive ability to different detected objects and seeing conditions is being investigated in Beijing Institute of Technology. When seeing conditions are good, and the Shack-Hartmann wave front sensor of adaptive optics system is working under very low light level, the subaperture of Shack-Hartmann sensor need to be adjusted larger than that when it is working under higher light level and the seeing condition is not good enough. By setting a motorized zoom lens in front of the Shack-Hartmann WFS of a conventional adaptive optics system, the subaperture array of the WFS can be adjusted from 8 X 8 to 2 X 2 in the pupil of the telescope with step by step if necessary. With this method, the overall performance of adaptive optics system can be boosted. Based on an adaptive optics system of the 1.2 meter telescope, a discussion on the noise analysis of Shack-Hartmann WFS associated with subaperture optimization is presented in this paper.

The methods of evaluating the astronomy-using CCDs in Yunnan Observatory CCD-testing Lab are introduced, concerning the evaluation of linearity, noise, gain, quantum efficiency and transfer efficiency, etc.

A new method of measuring the PRN of CCD device is presented the PRN of CCD device can be determined quickly and accurately by this method, the effect of illuminance distribution nonuniformity on the measurement of CCD device PRN is eliminated.

This paper presents a system for measurement of CCD parameters that combines a photo-injection system and auto- focus systems. In the photo-injection system, a reverse microscope with plano-achromatic objective is used to produce a small light spot of (Phi) 2 micrometers . In the auto- focus system, astigmatic auto-focus method is applied. The auto-focus signal is detected by a simulation quadrate simulated by CCD. A piezoelectric transducer with high sensitivity and resolution is used to drive the focusing objective for a real-time control of the position of the small light spot which was required to be injected into one of pixels of CCD measured.

Cadmium zinc telluride (CsZnTe) has been applied as a X-ray and gamma-ray radiation detector due to its large bandgap and high atomic number which gives low leakage current and good absorption efficiency. In addition, the CdZnTe detectors can be operated at room temperature with very good energy resolution and excellent spatial resolution. The main challenges in fabricating a large area CdZnTe strip detector array are the requirements of low leakage current in the individual strips of each detector and the good adhesion of the pad metal to the CdZnTe surface for wire bonding. The Detector Systems Branch at Goddard Space Flight CEnter has successfully fabricated the double sized CdZnTe strip detectors for a 6 X 6 array. The strip detector array has 36 double sided detectors with each detector having 127 strips and a guard ring on each side with a spatial resolution < 100 micrometers . The total area of the array is 60 cm² with 762 X 762 strips to give 580,000 pixels - a factor of 100 better than other CdZnTe or scintillator arrays. In this paper, we will present our novel processing for fabricating such high performance strip detectors. The leakage current, interstrip resistance and energy resolution were studied as a function of different etchants/time and post-annealing temperature. The effects of chemical etching and post annealing on the CdZnTe surface and interface property were also discussed.

High resolution infrared imaging system calls for very long scanning arrays with several thousands of detectors and high performance. This paper presents the recent technological developments an the electrooptical performances obtained at LETA/LIR on 1500 detector linear HgCdTe arrays working in the 3-5 and 8-10 micrometers spectral ranges. These very large arrays have an indirect hybrid architecture composed of butted HgCdTe PV detection circuits and Si CMOS readouts hybridized on a fanout substrate. Defect free dicing and butting, respecting the detector pitch, is made by accurate and non damaging techniques.

Sofradir, the European company totally dedicated to second and third generation of IR detectors has focused its activities on development and production based on MCT material. As a matter of fact, Sofradir is one of the sole companies in the world able to master the MCT technology for SW, MW, and LW and then to produce this type of arrays in good conditions allowing affordable prices. This activity covers TDI long linear arrays and staring arrays. Performances of TDI arrays like the 480 X 6 or staring arrays like the 320 X 240/ 256 X 256 will be presented. Then the most advanced activities in France in the field of IR detectors will be presented. This will cover the new MCT 640 X 480 but also the approach of QWIPs and microbolometers.

Rapid progress in quantum well IR photodetectors (QWIPs) technology has made it possible to develop large format, and high uniformity QWIP focal plane arrays (FPAs) for IR imaging sensor applications. So far, all QWIP FPAs are made of n-type GaAs/AlGaAs material systems grown on GaAs substrates due to the maturity of this material system and excellent detector performance. However, due to quantum selection rules, normal incidence absorption is forbidden in n-type QWIPs. As a result, n-type QWIP FPAs are required to use dielectric or metal gratings to efficiently couple the IR radiation into the quantum wells under normal incidence illumination. On the other hand, normal incidence absorption is allowed in p-type QWIPs without using the grating couplers. This property makes p-type QWIPs potentially more attractive for large format FPA applications. This paper will review the recent development in both n-type and p-type QWIPs for mid-wavelength, long-wavelength and very long wavelength IR detections. The basic device physics, structures, and performance parameters such as dark current, spectral responsivity, and detectivity for both n-type and p-type QWIPs will be depicted. Finally, a comparison of the advantages and drawbacks of n-type and p-type QWIPs will also be given.

This paper addresses the following topics at an easy-to- understand physics level. We present simple analytical formulas in estimating the performance characteristics of quantum well IR photodetectors (QWIPs), including detectivity and temperature for background limited IR performance. We identify key parameters and their relations to the detector performance. We point out possible directions for future work to improve the performance. Features and opportunities of the QWIP technology are also pointed out and discussed. The shortcomings are also discussed, including low operating temperature. A brief comparison with other IR detector technologies is made. Note that all discussions here apply to QWIPs based on GaAs using electron intersubband transitions.

In recent years, many research groups in the world have demonstrated large format quantum well IR photodetector (QWIP) focal pane arrays for various thermal imaging applications. QWIPs as opposed to conventional low bandgap IR detectors, are limited by thermionic dark current and not tunneling current down to 30K or less. As a result the performance of QWIPs can be substantially improved by cooling from 70K to 30K. Cooling does not induce any nonuniformity or 1/f noise in QWIP focal plane arrays. In this paper, we discuss the development of highly uniform long-wavelength QWIPs for astronomical applications.

A novel 48 micrometers cutoff wavelength ((lambda) _c) Si far-IR (FIR) detector is demonstrated. Internal photoemission over a Si interfacial work-function of a homojunction consisting of molecular beam epitaxy grown multilayers is employed. The detector shows high responsivity over a wide wavelength range with a peak responsivity of 12.3 +/- 0.1 A/W at 27.5 micrometers and detectivity D* of 6.6 X 10¹⁰ cm (root) Hz/W at 4.2 K. The (lambda) _c and bias dependent quantum efficiency agree well with theory. Based on the experimental results and the model, Si FIR detectors with high performance and tailorable (lambda) _cs can be realized using higher emitter layer doping concentrations.

Over the past several years, uncooled IR detectors and focal plane arrays have been rapidly developed. Impressive progress has been made in both resistive microbolometers and pyroelectric thin-film detectors with noise equivalent temperature differences projected to be 10 to 20 mK with F/1 optics for such structures. Noise equivalent temperature of 50 mK bulk pyroelectric detectors and thin film resistive microbolometers are already demonstrated and in production. Other novel schemes, such as bimaterial capacitors, are also promising for uncooled IR detection. The US Army Research Laboratory is involved in developing ferroelectric materials to take advantage of the pyroelectric properties. The goal is to develop crystal oriented thin films to further improve detector performance. In this presentation, the operating principle of resistive microbolometers and pyroelectric detectors, and recent progress of uncooled RI focal plane arrays are discussed. In addition, the uncooled RI detector program at the Army Research Laboratory, that includes research facilities for and research efforts toward uncooled detectors and focal plane arrays is presented.

Rapid progress in the development of quantum well IR photodetectors (QWIPs) has made it possible to manufacture sensitive, large area, highly uniform GaAs/AlGaAs staring focal plane arrays (FPAs). Because of the maturity of the GaAs growth technology, the stability of the material system, and good performance in the long wave IR spectral region, QWIP technology development is supported by the Ballistic Missile Defense Organization. In comparing Mercury Cadmium Telluride (MCT) to QWIPs it is found that QWIPs are comparable or superior to MCT at 8 to 12 microns for some applications and can be used at wavelength in excess of 12 microns.QWIPs have greater flexibility in spectral range and offer the possibility of a superior multicolor capability using a single growth and fabrication processing technique. This makes simultaneous detection of two and more colors easier to achieve than in MCT. On the other hand, QWIP sensitivity is currently below that of MCT. Also MCT arrays can operate at higher temperatures with lower dark current than QWIPs. However, QWIPs produce a superior image quality due to better spatial and spectral uniformity. For example, high pixel to pixel uniformity allows QWIPs to perform well in interceptors where window heating generates a high thermal background, which must be accurately subtracted. This paper reviews the status of QWIP technology and presents several potential applications for QWIP sensors. All of these applications are for ballistic missile defense.

Two extended area reference blackbodies, covering temperature range from 100 K to 900 K, have been designed and built by VNIIOFI and Vega International, Inc., for German Institute of Space Sensor Technology. The design objectives were to develop Plankian sources for high accuracy IR calibrations; provide, where possible, both high vacuum and atmospheric operation capabilities for easier achievable calibration traceability; and attain compact design to serve as a portable transfer standard. Target technical specifications for the low temperature blackbody BB100 include 100 mm full aperture, +/- 12 degree viewing angles, 0.999 effective spectral emissivity in 3 micrometers to 15 micrometers band, 100 K to 450 K temperature range, 50 mK temperature uniformity across aperture and, finally, 30 mK temperature setting/measurement accuracy. An employed design was selected after conceptual design study, which involved extensive thermophysical modeling and optimization. A finite element method has been applied to calculation of temperature distribution. Effective emissivity simulation was realized by the Monte Carlo method. The result of computer modeling of temperature distributions and effective emissivity are presented. Both target specifications and results of BB characterization are provided. Results of investigation confirm validity of selected approach and assumptions. Possibilities of further improvement of blackbodies performance are discussed.