Performance data from a new InGaAs focal plane array (FPA) camera is presented. The camera was developed specifically for low-light scientific NIR imaging and spectroscopy applications that often require long integration times and lower dark noise. While commercial InGaAs FPA cameras offer no or minimal cooling to reduce troublesome dark current, the cameras meant for scientific applications offer -100°C or deeper cooling. The performance comparison between uncooled and cooled states is presented. Other operating specifications such as read noise, read out rate and linearity are optimized through careful design of electronics. The improved performance of cooled InGaAs cameras allows detection of low light fluorescence from single walled nanotubes. The availability of such low noise InGaAs cameras is enabling researchers to perform quantitative NIR imaging and spectroscopy measurements in novel applications ranging from semiconductor failure analysis to singlet oxygen detection.

This paper reports performance data for back-illuminated planar n-on-p HgCdTe electron-initiated avalanche photodiode (e-APD) 4×4 arrays with large-area unit cells (250×250 μm²). The arrays were fabricated from p-type HgCdTe films grown by LPE on CdZnTe substrates. The arrays were bump-mounted to fanout boards and were characterized in the back-illuminated mode. Gain increases exponentially with reverse bias voltage, and gain versus bias curves are quite uniform from element to element. The maximum gain measured is 648 at -11.7 V for a cutoff wavelength of 4.06 μm at 160 K. For the same reverse bias voltage, the gain at 160 K for elements with two different cutoff wavelengths (3.54 and 4.06 μm at 160 K) increases exponentially with increasing cutoff wavelength, in agreement with Beck's empirical model for gain versus voltage in HgCdTe e-APDs. Spot scan data show that both the V=0 response and the gain at V=-5.0 V are quite uniform spatially over the large junction area. To the best of our knowledge, these are the first spot scan data for avalanche gain ever reported for HgCdTe e-APDs. Capacitance versus voltage data are consistent with an ideal abrupt junction having a donor concentration equal to the indium counterdoping concentration in the as-grown LPE film. Calculations predict that bandwidths of 500 MHz should be readily achievable in this vertical collection geometry, and that bandwidths as high as 3 GHz may be possible with careful placement of the junction relative to the compositionally interdiffused region between the HgCdTe LPE film and the CdZnTe substrate.

We report on the development of InAs/GaSb type-II superlattice focal plane arrays (FPAs) for missile warning systems in airborne platforms. The FPA fabrication technology was developed on the basis of monospectral superlattices for the MWIR (3-5 μm) spectral range. A monospectral 288×384 MWIR camera with 24 μm pixel pitch, a noise equivalent temperature difference (NETD) better than 14 mK and a background-limited performance (BLIP) up to 92 K is demonstrated. Based on the monospectral technology, the first bispectral superlattice camera was realized. The dual color 288×384 superlattice camera features simultaneous, pixel-registered detection of both spectral channels between 3-4 μm and 4-5 μm with a NETD better than 30 mK and 17 mK, respectively. Hence, spatial or temporal registration problems, which are common to most dual color and dual band infrared imagers are solved with the new bispectral MWIR missile alerting sensor.

Bechtel Nevada/NSTec recently announced deployment of their fifth generation streak camera. This camera incorporates many advanced features beyond those currently available for streak cameras. The arc-resistant driver includes a trigger lockout mechanism, actively monitors input trigger levels, and incorporates a high-voltage fault interrupter for user safety and tube protection. The camera is completely modular and may deflect over a variable full-sweep time of 15 nanoseconds to 500 microseconds. The camera design is compatible with both large- and small-format commercial tubes from several vendors. The embedded microprocessor offers Ethernet connectivity, and XML [extensible markup language]-based configuration management with non-volatile parameter storage using flash-based storage media. The camera's user interface is platform-independent (Microsoft Windows, Unix, Linux, Macintosh OSX) and is accessible using an AJAX [asynchronous Javascript and XML]-equipped modem browser, such as Internet Explorer 6, Firefox, or Safari. User interface operation requires no installation of client software or browser plug-in technology. Automation software can also access the camera configuration and control using HTTP [hypertext transfer protocol]. The software architecture supports multiple-simultaneous clients, multiple cameras, and multiple module access with a standard browser. The entire user interface can be customized.

This study aims at the development of non-contact dry eye diagnosis based on an infrared thermal imager system, which was used to measure the cooling of the ocular surface temperature of normal and dry eye patients. A total of 108 subjects were measured, including 26 normal and 82 dry eye patients. We have observed that the dry eye patients have a fast cooling of the ocular surface temperature than the normal control group. We have developed a simplified algorithm for calculating the temperature decay constant of the ocular surface for discriminating between normal and dry eye. This study shows the diagnostic of dry eye syndrome by the infrared thermal imager system has reached a sensitivity of 79.3%, a specificity of 75%, and the area under the ROC curve 0.841. The infrared thermal imager system has a great potential to be developed for dry eye screening with the advantages of non-contact, fast, and convenient implementation.

A highly sensitive image sensor for single photon imaging has been developed. The sensor (referred as an intensified EBCCD here) contains a photocathode, a microchannel plate (MCP) and an electron-sensitive CCD in a vacuum tube. In response to incident photons, electrons emitted from the photocathode are multiplied once by the MCP, further by the CCD and read out. Either an image intensifier containing MCPs or an EBCCD containing an electron-sensitive CCD has sensitivity for single photon by itself, however, many intense white spot-noise appear on output image and degrade the image quality seriously at such high-gain operation. In the case of intensified EBCCD reported here, since both the MCP and the electron-sensitive CCD are used for electron multiplication, high gain for single photon detection is available in total at low gains of both devices. This operation reduces the noise drastically, and improves the image quality. We have developed the intensified EBCCD with a GaAsP photocathode for high quantum efficiency, and evaluated the performance. Comparing with conventional cameras, such as an EM-CCD and an image intensifier, the intensified EBCCD shows superior detection capability at especially low-light level, that is single photon imaging.

We describe a 2-D fully differential Readout Integrated Circuit (ROIC) designed to convert the photocurrents from an array of differential metal-semiconductor-metal (MSM) detectors into voltage signals suitable for digitization and post processing. The 2-D MSM array and CMOS ROIC are designed to function as a front-end module for an amplitude modulated/continuous time AM/CW 3-D Ladar imager under development at the Army Research Laboratory. One important aspect of our ROIC design is scalability. Within reasonable power consumption and photodetector size constraints, the ROIC architecture presented here scales up linearly without compromising complexity. The other key feature of our ROIC design is the mitigation of local oscillator coupling. In our ladar imaging application, the signal demodulation process that takes place in the MSM detectors introduces parasitic radio frequency (rf) currents that can be 4 to 5 orders of magnitude greater than the signal of interest. We present a fully-differential photodetector architecture and a circuit level solution to reduce the parasitic effect. As a proof of principle we have fabricated a 0.18 μm CMOS 32x16 fully differential ROIC with an array of 32 correlated double sampling (cds) capacitive transimpedance amplifiers (CTIAs), and a custom printed circuit board equipped to verify the test chip functionality. In this paper we discuss the fully differential IC design architecture and implementation and present the future testing strategy.

LWIR and Multi-color LWIR Focal Planes are being developed for a variety of Space applications. A variety of Focal Plane array technologies, that includes HgCdTe, PbSnTe and other novel technologies are being developed. These detectors FPAs will require High quality two-dimensional, small unit cell, Silicon CMOS based ROICs for efficient read-out circuits. This Paper will discuss some of the salient features of various approaches being developed for the IR focal plane applications. We will also present Trade-off analysis for design of a trans-impedance input amplifier with reset and compact signal average for low noise performance. We will also discuss the various approaches for design of an A/D converter with high linearity and speed. We will discuss approaches to achieve ROIC with low noise floor, high dynamic range and high frame rate.

Recursive Limited Frame Integration was proposed as a way to improve frame integration performance and mitigate issues related to high data rate needed to support conventional frame integration. The technique uses two thresholds -one tuned for optimum probability of detection, the other to manage required false alarm rate, and places integration process between those thresholds. This configuration allows a non-linear integration process that, along with Signal-to-Noise Ratio (SNR) gain, provides system designers more capability where cost, weight, or power considerations limit system data rate, processing, or memory capability. However, Recursive Frame Integration Limited may have performance issues when single-frame SNR is really low. Recursive Adaptive Limited Frame Integration was proposed as a means to improve limited integration performance with really low single-frame SNR. It combines the benefits of nonlinear recursive limited frame integration and adaptive thresholds with a kind of conventional frame integration. Adding the third threshold may help in managing real time operations. In the paper the Recursive Frame Integration is presented in form of multiple parallel recursive integration. Such an approach can help not only in data rate management but in mitigation of low single frame SNR issue for Recursive Integration as well as in real time operations with frame integration.

A recently developed scene-based nonuniformity correction algorithm for focal plane array (FPA) sensors named Crossing Path Scene-Based Algorithm (CPSBA) is present. The goal of this thesis is to design and evaluate scene-based nonuniformity correction algorithms that are able to suppress fixed pattern noise without need for external hardware such as temperature reference equipment. In particular, algorithms should be able to accurately estimate motion between images and use this knowledge to improve performance. The algorithms have been tested by using real image data from existing infrared imaging systems with good results.

Damage inspection of the large aperture components is required for Large, high-power laser systems. Dark-field imaging technology is used to enhance resolution of defects. Because there are several of the optics which are laid with Brewster angle in optics online inspection and the image collected by CCD includes many noises, so the image are quite complex. A kind of image processing method is introduced, which is based on classical method about edge detection. Gray restrain is used and the relations between the pixel and its eight neighbours are considered in calculating the gradient. The defect size is measured and damage defect of optics is analyzed using the image processing methodology. The new approach produces nice result.

This model was developed to provide a means for comparative assessments of HgCdTe FPA's and sensors operating in the infrared spectral bands that coincide with the atmospheric windows - (SW1(1.5-1.8μ), SW2(2-2.5μ), MW(3-5μ), and LW(8-12μ). As a true imaging model it also functions as an assessment tool for single-band imagery and for multi-color imagery. The HgCdTe model characterizes both n-on-p and p-on-n homojunctions and heterostructures. Diffusion and depletion dark currents and RoA's are calculated for the three common configurations (mesa heterojunction, planar ionimplanted or diffused junction, and the vertically integrated photodiode). The model places the specified FPA into an optical system, evaluates system performance (NEI, NETD, MRTD, and SNR) and creates two-point corrected imagery complete with 3D noise image effects. This model was exercised here as a predictive tool for performance of state-of-the- art detector arrays in optical systems in the four spectral bands (atmospheric windows) from the SW to the MW (1.5- 1.8, 2.0-2.5, 3.4-4.2 and 4.5-5.0 um) which are the bands commonly considered for hot target and plume exhaust detection. Results from the literature and model runs for various target and scene sets show promise for HgCdTe FPA's and sensors developed for the 2-2.5 μm band for a variety of missions such as threat detection from UAV or satellite platforms, perimeter defense, and high-altitude intercepts.

This paper reports on a model developed to predict bolometer performance in its environment, where the environment consists of thermal, optical and electrical components. Two complementary methods were employed to predict performance. The first solves the heat balance equation for the bolometer in its circuit and its thermal environment with known values of heat capacitance, thermal conductance, absorptance, temperature coefficient of resistance and the userdefined bias current (either constant or pulsed). This iteration yields a bolometer temperature rise, and a corresponding change in resistance and voltage. This is the signal part of the equation. The second method is required to calculate the total bolometer noise. It uses equations derived from the literature to predict bolometer noise, response, NEP and NETD from first principles for the four types of noise generated in thermal detectors (thermal fluctuation noise, background fluctuation noise, johnson noise and 1/f noise). Thermal conductance and heat capacities are calculated using all the elements of the bolometer structure such as the silicon nitride structure, the VOx coating, and the nichrome electrical leads. Using a calculation of the full spectral irradiance on the bolometer from the scene and the dewar and a userdefined bolometer element spectral absorption, the model will accurately assess performance in any environment. The model also employs a 3-D noise model and provides synthetic images of PSF-blurred bar targets for NETD and MRTD predictions.

We investigated on cyanine dye (HQ) in Langmuir and Langmuir-Blodgett (LB) films by surface pressure-area (π-A) isotherms, UV-visible and polarized UV-visible spectra as well as small angle x-ray diffraction (SAXD) measurement. It is found from the isotherms that there is a critical point on Langmuir films near the area 0.8nm²/molecule for HQ LB films with and without Cd²⁺ ions respectively and suggested that the facts should result from the phase transition due to the change of molecular tilt angle on surface of sub-phase. UV-visible spectra indicated a uniform film transfer. The orientation angle of HQ molecular chromophore in LB films was measured by polarized UV-visible absorption spectra, and the result showed that the angle with respect to the substrate surface was 65 and 59 degree without and with Cd²⁺ ions respectively, which are agreement with those obtained from the surface pressure-area isotherm. It is suggested that the arrangements of the HQ molecule in LB films incorporating Cd²⁺ ions was more compact than those without Cd²⁺.

Wide dynamic range gating photosensor modules has been design for LIDAR-RADAR applications on base R7400U (active area 8 mm. diameter) R7600U (active area 18x18 mm.) Hamamatsu photomultiplier tubes. The photomultiplier tubes R7400U, series have two kinds of photocathode: low resistance semitransparent multialkali photocathodes and semitransparent bialkali photocathodes with large resistance. Different kinds of photocathodes require different approach to gating circuits design. High-speed pulse gating (gating rise time 10 nsec, setting time 40 nsec for 99%) has been used for enhancing of target contrast at ocean optic application for both kinds: semitransparent bialkali and semitransparent multialkali photocathodes. Wide dynamic range (50 dB of optical power) has been achieved by optimizing of applied to dynodes voltages. Compression up to 30 dB has been used for following output signal digital processing. Hamamatsu photosensitive modules were used in the two system receivers in pulsed LIDAR system. The system was mounted on the bow of the R/V New Horizon and collected data from August 25 thru September 8, 2005 as part of the LOCO field test in Monterey Bay. Approximately 4 million LIDAR profiles were collected during this period. During the field test the profiles were processed to show relative changes in water optical properties and to reveal water column structure in real time.

Measurements and lidar calculations have been made for 1574 nm laser light pulsed through hydrocarbon smoke generated by wood. A pulsed laser signal is directed to the end of wood smoke filled chamber. The signal is reflected back through the smoke by a mirror and the end of the chamber and the total returned energy is measured as a function of the smoke density. The results are compared with a lidar calculation using Rayleigh-Debye-Ganz scattering theory for fractal aggregates. Measurements and calculations are also made of the total backscattered signal for a smoke chamber with a non-reflecting surface. Relatively good agreement between the theory and experimental results are achieved in both cases. These results are used in the feasibility studies of a FireLidar active imaging system being developed for use in search and rescue in smoke and flame environments.

A systematic first-principles calculation of the linear and second-order optical susceptibilities as functions of frequency for CsGeBr₃ is presented. Specifically, we study the relation between the structural properties and the optical responses. Three structural deformation factors, Δα, d_Ge, d_X are used to express the degree of distortion from the ideal perovskite structure in bond angle, Ge position, and anion position, respectively. Based on our first-Principles studies, we find that Δα and d_Ge increase, while d_X decreases as we substitute the halogen ion from Cl to Br and then to I. The dielectric function and the second harmonic generation coefficient are also found to increase with increasing Δα and d_Ge. Our calculation indicates that the direct bandgap, E_g, of CsGeX₃ occurs at the R-point for all three compounds, and its magnitude decreases as Δα and d_Ge increase (i.e. E_g(CsGeI₃) < E_g(CsGeBr₃) < E_g(CsGeCl₃)). Our partial density of states (PDOS) analysis reveals that the valence band maximun (VBM) and conduction band minimum (CBM) are mainly associated with the p-orbitals of Germanium. Interband and intraband analysed results for (formula available in manuscript) in C_sG_eBr₃ can be separated into two main groups of peaks. One was contributed from the magnitude electronic bandgap; the other part was recognized to be attribution from the distortional structural factors. The magnitudes of (formula available in manuscript) were in the same manner with some reported experiment near the band gap.

A conventional p-i-n photodetector designed for absorption in the C-band region has been integrated with a low-cost all-dielectric based filter for single wavelength detection at 1542nm. The dielectric based filter of SiO₂ cavity layer sandwiched between two pairs of highly reflecting Si₃N₄/SiO₂ mirrors are deposited by PECVD. The full width at half maximum (FWHM) of the reflectance spectra for the filter is measured to be 9.2nm. Reflectance measurement indicates a transmittivity of 83.6% at 1542nm, while reflecting all other wavelengths from 1400 to 1730nm. Dark-current measurement of the photodetector is in the range of 10^-8A at a reverse bias voltage of -2V. A photocurrent enhancement of 4 orders of magnitude, at an incident wavelength of 1542nm for a reverse-bias voltage of -2V is observed.

This paper reviews arsenic (As) dopant activation processes in the various forms of epitaxial MCT. Extrinsic doping of MCT is an important part of MCT technology and As doping is preferred as it is a shallow acceptor dopant with low diffusivity and 100% activation can be achieved under the correct growth and/or post-growth annealing conditions. It is, however, amphoteric so that under Te-rich growth conditions it can be incorporated as a donor (As_Hg) and under metal-rich conditions as an acceptor (As'_Te). For As concentrations up to ~ 2 × 10¹⁸ cm^-3 the amphoteric model provides a satisfactory basis for explaining the behavior on annealing layers at temperatures above ~ 250 ^oC. Under Te-rich conditions in LPE- and MBE-grown layers can be either compensated n-type or the As can be inactive. The quantitative model of Schaake is used to obtain an expression for the activation anneal time in terms of As concentration, layer thickness, composition and temperature. Layers grown by MOVPE can show up to 100% acceptor activation if the stoichiometric conditions during the CdTe growth cycle of the interdiffused multilayer (IMP) process are maintained as metal-rich. In as-grown MBE layers the evidence indicates that As is incorporated in the form of tetramers that can dissociate at higher temperatures. The issue of establishing whether layers are electrically intrinsic at the annealing temperatures used to activate the As acceptor in LPE and MBE layers is also discussed.

This paper reports temperature-dependent DC and small-signal RF characteristics of a 0.4-mm-radius sapphire-based GaN p-i-n diode between -60°C and 175°C. Deep levels approximately 1 eV below the conduction band were observed in both persistent photo-conductance and photo-capacitance measurements. Self-heating effects were also observed and modeled with the measured thermal resistance and time constant. Based on these characteristics, an equivalent-circuit model was constructed, which accurately predicted the temperature-dependent DC and RF characteristics of the diode.

We report on the characteristics of two InP-based quantum cascade detectors (QCDs) whose responses are centered at 5.35 and 9 μm. The working principle is based on a vertical intersubband transition followed by a carefully designed extraction cascade, which is adapted to the LO-phonon energy. This device architecture leads to 10 K responsivities R of 8 and 26 mA/W and background limited detectivities D*BLIP of 1.7 x 10¹⁰ and 0.9 x 10¹⁰ jones, for the 5.35 μm and the 9 μm device, respectively. The temperature up to which background limited operation is seen is 115 K for the 5.35 μm device and roughly 65 K for the 9 μm detector. Designed for zero bias operation, QCDs produce a minimal dark current and therefore suffer very little from dark current noise. In addition, capacitance saturation at long integration times can be avoided, making them ideal devices for large focal plane arrays. The 5.35 μm detector was tested at high speed and room temperature. An optical beating signal generated by two slightly de-tuned singlemode quantum cascade lasers was used to test the detector's response at frequencies of up to 23 GHz.

Recently the demand for high-capacity optical storage systems compatible with CD, DVD, and Blue is growing. We designed the Vertical NIP photodiode with a diameter of 700um and the trans-impedance circuits by using 0.6um BiCMOS process. The measured sensitivity of the photodiode is 0.25, 0.42, and 0.48A/W for 405, 650, and 780nm wavelength lights, respectively. The capacitance of the PD is 4.5pF. Monitor PDIC for detecting triple wavelength lights is presented in this paper. The complete monitor PDIC with the NIP photodiode of 700um in diameter occupies 1900um*1200um. -3dB bandwidth is 110MHz and the temperature drift of output voltage is 3.2%.

A variety of single color and multicolor Electro Optical/Infrared (EO/IR) Focal Plane Array technologies are being developed for Space System Applications. There has been a significant research and development effort to date to improve the technology in single and multicolor wavelength bands that include the SWIR, MWIR and LWIR spectral regions. This review paper will address the current technologies and new ones that will be useful for near term applications and also can provide further improvements for future systems applications.

Coded aperture imaging (CAI) has evolved as a standard technique for imaging high energy photon sources and has found numerous applications. Coded aperture arrays (CAAs) are the most important devices in the applications of CAI. In recent years, many approaches were presented to design optimum or near-optimum CAAs. Uniformly redundant arrays (URAs) are the most successful CAAs for their cyclic autocorrelation consisting of a sequence of delta functions on a flat sidelobe which can easily be subtracted when the object has been reconstructed. Unfortunately, the existing methods can only be used to design URAs with limited number of array sizes and fixed autocorrelative sidelobe-to-peak ratio. In this paper, we presented a method to design more flexible URAs by means of a global optimization algorithm named DIRECT. By our approaches, we obtain various types of URAs including the filled URAs which can be constructed by existing methods and the sparse URAs which never be constructed and mentioned by existing papers as far as we know.

System architecture has a significant impact on software performance. In this manuscript, a method to increase the performance of the microprocessors and FPGA based systems using pipeline processing, is presented. An improved implementation using this concept, for image and display processing, providing real time vision applications, is described.

For the first time the photo-EMF measurements were carried out for CdTe crystals doped with V atoms as a result of the photogeneration of carriers from deep impurity centers to the conduction band and the tilted geometry was applied that allowed two-mentional monitoring of the vibration source. The CdTe:V crystals were excited by a He-Ne laser with λ=1.15 μm (&barh;ω=1.08 eV) and P=2 mW. The mechanism of appearance of the holographic current in the CdTe:V crystals (adaptive IR-photodetectors) taking into account of real defect structure was proposed. The frequency dependence of ac photo-EMF (holographic) current for the CdTe:V crystal was measured. It was shown that a low cutoff frequency for the laser intensity I=0.2 mW/mm² equals 6.0 kHz that corresponds to the response time of 26 μsec.

This paper describes the Militarily Critical Technologies Program's (MCTP) Developing Science and Technologies List (DSTL) sponsored by the Office of the Director, Defense Research and Engineering (DDR&E). It outlines the unique Technology Working Group (TWG) process developed by the Institute for Defense Analyses (IDA) to support the MCTP and specifically the DSTL. It also outlines the approach used to determine the technologies that are included as well as how worldwide technology capability assessments are incorporated into the review process. As an example, this paper outlines the technology parameters associated with Deformable Mirrors and identifies how both military and commercial applications have an input into the TWG process. The membership of the TWGs is explained and its role identified. Each TWG has a broad base, including representatives from government, industry and academia who are technical experts in their respective fields.

Electrons generated in photocathodes have a range of energies and may exit the outer layer of the photocathode with a certain distribution (possibly isotropic). In a proximity-focussed image intensifier where there is a strong electric field between the photocathode and the micro-channel plate (MCP) electrons ejected at an angle will follow a trajectory defined by the exit velocity of the electron and the strength of the field. A small spot of light projected onto the photocathode will result in a point spread function determined by the size of the gap, the field applied across it and the magnitude of the radial energy component of the electrons. By using photon counting and centroiding techniques, the events occurring on the screen of an image intensifier have been integrated and used to measure the diameter of the projected spot (~5 micron diameter) thus giving a measure of the resolution of the tube. At short (UV) wavelengths the spread of electron energies is larger and the average radial energy component is larger than at longer (visible) wavelengths. Hence the resolution is better in the visible. Resolution measurements as a function of wavelength of solar blind and S20 intensifiers show a dip in the measured spot size and hence a localised peak in the resolution in a short range of wavelengths in the UV. Combined with data obtained from measuring the electron energy distribution that shows a narrowing of the distribution in the same region, this shows evidence of multiple photoelectrons being generated within the photocathode. Such electrons would have lower energies resulting in higher measured resolution and a narrower electron energy distribution profile.

The technique of imitating computer modeling offered for the purpose of the quality estimation of the electro-optical devices for observation. Specifically used as example the night vision devices. The following questions are considered: a choice of quality estimation criteria; a choice of set of external operating conditions; development of structure of computing model and the generalized algorithm of imitating modeling; development of base algorithms of modeling.

The scintillating fiber camera is a type of three-dimensional track detector. Using this camera, we can observe the scintillation track produced along the path of a charged particle, and from its scintillation yield can determine the linear energy transfer (LET) distribution of the charged particle. Such observations are also possible for recoil (charged) particles produced by fast neutrons. From these data, we can estimate the LET distribution of individual charged particles or that of recoil particles produced by neutrons; and finally, we can estimate the dose equivalent due to charged particles and/or fast neutrons. For use as a dosimeter for fast neutrons produced by the interaction between cosmic-ray particles and wall materials of a manned spaceship in space, a 52 mm cubic scintillating fiber camera with a 75 mmΦ gated-image intensifier with a maximum counting rate of 30 Hz was constructed. The dosimeter consists of a stack of scintillation fibers with a sensitive volume of 52 mm × 52 mm × 52 mm and a 75 mm diameter image intensifier for readout from the scintillation fibers. The scintillation yields were measured for high-energy heavy ions such as carbon and argon ions. An energy resolution of 12% full-width half-maximum (FWHM) was obtained for penetrated argon ions of 650 MeV/n. These results demonstrate that this type detector is very useful as a dosimeter for high-energy cosmic rays and their secondary neutrons.

Avalanche photodiodes (APDs) are being widely utilized in various application fields where a compact technology computer aided design (TCAD) kit capable for APD modeling is highly demanded. In this work, based on the advanced drift and diffusion model with commercial software, the Crosslight APSYS, avalanche photodiodes, especially the InP/InGaAs separate absorption, grading, charge and multiplication (SAGCM) APDs for high bit-rate operation have been modeled. Basic physical quantities like band diagram, optical absorption and generation are calculated. Performance characteristics such as dark- and photo-current, photoresponsivity/multiplication gain, breakdown voltage, excess noise, frequency response and bandwidth etc., are simulated. The modeling results are selectively presented, analyzed, and some of results are compared with the experimental. Device design optimization issues are further discussed with respect to the applicable features of the Crosslight APSYS within the framework of drift-diffusion theory.

This work describes the characterization of a quadrant-type silicon photodiode that detect visible light and is designed using CMOS integrated circuit technology, peaking in 550 nm wavelength. The quadrant detector (QD) derives photocurrents by projecting a spot of light on four photodiodes placed close to each other on a silicon common substrate. The photodetector is square shaped with 2.25 mm² per active area by each quadrant and the size of the device is 9mm². Its transition region between the adjacent cells had a narrow width of 30 μm. The technology to develop position sensitive detectors of four quadrant optimizing geometry to increase sensitivity is described. In addition, the performance on applying the QD to shape a recovering system is investigated.

Infrared camera systems may be made dramatically smaller by simultaneously collecting several low-resolution images with multiple narrow aperture lenses rather than collecting a single high-resolution image with one wide aperture lens. Conventional imaging systems consist of one or more optical elements that image a scene on the focal plane. The resolution depends on the wavelength of operation and the f-number of the lens system, assuming a diffraction limited operation. An image of comparable resolution may be obtained by using a multi-channel camera that collects multiple low-resolution measurements of the scene and then reconstructing a high-resolution image. The proposed infrared sensing system uses a three-by-three lenslet array with an effective focal length of 1.9mm and overall system length of 2.3mm, and we achieve image resolution comparable to a conventional single lens system having a focal length of 5.7mm and overall system length of 26mm. The high-resolution final image generated by this system is reconstructed from the noisy low-resolution images corresponding to each lenslet; this is accomplished using a computational process known as superresolution reconstruction. The novelty of our approach to the superresolution problem is the use of wavelets and related multiresolution method within a Expectation-Maximization framework to improve the accuracy and visual quality of the reconstructed image. The wavelet-based regularization reduces the appearance of artifacts while preserving key features such as edges and singularities. The processing method is very fast, making the integrated sensing and processing viable for both time-sensitive applications and massive collections of sensor outputs.