The Stratospheric Observatory For Infrared Astronomy SOFIA will become operational with the next two years. It will be the biggest astronomical airborne observatory ever build, comprising a 3m-class telescope onboard a Boeing 747SP. A suite of first-light instruments is under development striving for cutting edge technology to make SOFIA a milestone in infrared astronomy. Here we present an overview over the instrumentation and an update on the current status.

Virtis-H is the high spectral resolution channel of the visible and infrared imaging spectrometer VIRTIS, an instrument of the ESA/ROSETTA mission devoted to the in-orbit remote sensing study of the comet P/46 Wirtanen. After successful tests and calibration, the flight model has been delivered to the European Space Agency for integration on the satellite before the launch foreseen in January 2003. The Virtis-H channel is a cross-dispersion spectrometer in the spectral range 2-5um with a resolution between 1200 and 3000. Its design consists in an afocal telescope-collimator off-axis parabola mirrors, a prism-grating system performing the cross-dispersion, and a three-lens objective imaging the entrance slit on a 436x270 HgCdTe array from Raytheon/IRCOE. At each recorded image, a full spectrum of the observed scene is reconstructed allowing the study of the fine spectral details of the coma and the cometary nucleus. The calibration have shown the fully compliance of the instrument performances with the simulations in terms of spectral resolution, radiometric accuracy and sensibility. For example, spectra of gas, water ice and mineral powders have been measured with Virtis-H showing either its ability to resolve fine spectral lines but also its sensitivity to low fluxes; furthermore, measurements on a 250K blackbody shows its sensibility to relative temperature variation lower than 0.5^oC..

The adjacency effect is discussed at coastal areas of main land and peninsula using VNIR and SWIR on ASTER sensor, although the cross-talk phenomenon is apparently noted on some SWIR. The purpose of the analysis is to derive optical characteristics of atmospheric aerosol. The aerosol model is in accordance to the dust-like model. This model is adopted to ASTER and MISR on Terra satellite. Data is the Atsumi Peninsula near Nagoya (34° 40'N, 134° 00'E) GMT1.55 on July 10,2000. The ASTER SWIR(1.65μm-2.395μm) cross-talk phenomenon is noted in the data. This is known as a result of a structure of ASTER sensor. It is relatively large (5-6 DN counts and 100 lines or 3km length). On the other hands, when ASTER observe heterogeneous surface of coastal water, the adjacency effect due to the scattering by atmosphere might partly be contaminated to the above effect. In the SWIR region of spectrum, molecular scattering is practically neglected. However, some aerosol model indicates strong scattering effect at SWIR wavelengths. The main results are (1) The Japan Main land indicates 6~20 times more effect than the peninsula on adjacent radiance from ocean water. (2) SWIR & VNIR exhibit similar adjacent effect which might indicate aerosol or large particles.

With the successful launch of BIRD satellite in October 2001, new possibilities of the observation of hot events like forest fires, volcanic eruptions a.o. from space are opened. The BIRD (Bi-spectral Infrared Detection) is the first satellite which is equipped with space instrumentation dedicated to recognize high temperature events. Current remote sensing systems have the disadvantage that they were not designed for the observation of hot events. Starting with the FIRES Phase A Study, the principle requirements and ideas for a fire recognition system were defined. With the German BIRD demonstrator mission, a feasible approach of these ideas has been realized and work now in space. This mission shall answer technological and scientific questions related to the operation of a compact bi-spectral infrared push-broom sensor and related to the detection and investigation of fires from space. The payload of BIRD is a multi-sensor system designed to fulfil the scientific requirements under the constraints of a micro satellite. The paper describes the basic ideas for fire detection and the estimation of fire temperature, fire size, and energy release in the sub-pixel domain and describes the technical solution for the infrared sensor system on board of BIRD.

The SPICAM Light optical package on the ESA Mars Express mission is dedicated to the nadir, limb, solar and stellar occultation observations in the UV and NIR spectral ranges. A lightweight (~0.7 kg) near infrared channel of this instrument employs an acousto-optic tunable filter (AOTF). To our knowledge it is one of the first spectroscopic applications of the AOTF on a civilian spacecraft. A single-pixel spectrometer will sequentially measure the spectrum of reflected solar radiation from Mars between 1 and 1.7 μm with spectral resolution of 3.5 cm^-1, and spatial resolution of ~6 km from 250-km Mars Express orbit. A fiber-coupled solar entry allows profiling of the Martian atmosphere in solar occultations. A chosen configuration of the AOTF conserves both polarizations allowing therefore spectro-polarimetry measurements. The main scientific objectives of the instrument are the measurements of vapor column abundance simultaneously with ozone (measured in the UV channel) and retrieving of H₂O profiles in solar occultations. The flight model of the instrument is assembled and calibrated. Future development of the instrument including employing a multipixel linear array for cross-track mapping and extension of the spectral range is discussed.

A compact high-resolution system consisting of an echelle spectrometer combined with an acousto-optic tunable filter (AOTF) for separation of diffraction orders is developed for space-borne studies of planetary atmospheres in the near IR range. This design allows to achieve a resolving power, λ/Δλ, of 20000-30000 within the mass budget of less than 4-5 kg with no moving parts. Only a small part of spectrum in one of high diffraction orders can be measured at a time, but thanks to flexibility of the AOTF that can be tuned by electrical command to a random wavelength various pieces of spectrum can be measured anywhere within the spectral range. This development can be used for accurate measurements of important atmospheric gases, such as CO₂ in terrestrial atmosphere, measurements of isotopic ratios and minor gases. An instrument based on this principle, has high potential for solar occultation sounding of the atmosphere of Venus and for the studies of the Earth, in particular for measurements of isotopes of water in the lower atmosphere, either in solar occultation profiling (tangent altitude <10 km), or observing solar glint for integral quantities of the components. Also, the atmosphere of Mars has never been observed at local scales with high spectral resolution. A functional laboratory model, consisting of 275-mm echelle spectrometer with Hamamatsu InGaAs 512-pixel linear array and AOTF, demonstrating the principle of the instrument, is discussed. The spectral range is 1-1.7 μm, and the resolving power obtained at 1.39 μm is λ/Δλ =30000. The next set up will cover the spectral range of 2.5-4.5 μm, which is more adequate for measurements of HDO and organic molecules.

The main ideas to test the optics of the LMT, based on the use of null screens are revised. The design method of an array of light sources located in such a way that, by reflection on the test surface, the images of these sources are aligned in a regular grid (square of radial) is qualitatively described. Some experimental results obtained with small surfaces are presented and some modifications to be implemented in order to improve the method will be discussed.

Balloon borne instruments offer opportunities for astronomical observation in an environment that is superior to many ground observatories and less expensive than space borne observatories. BLAST is an infrared astronomical telescope that will use a high altitude balloon as an observation platform. The BLAST telescope has a unique set of requirements: lightweight, low cost, zenith to horizon pointing, 10 arc-second pointing accuracy, high Strehl ratio far infrared/sub-milllimeter observation. The design of the BLAST telescope takes advantage of a pre-existing 2-m experimental lightweight carbon fiber mirror. Using this spherical primary, an aspheric secondary was designed to produce a diffraction limited telescope at 250 microns. The telescope metering structure was designed and fabricated using high stiffness, low mass, thermally stable carbon fiber. The secondary mirror was aggressively lightweighted and fabricated using state of the art diamond turning technology. Design was verified prior to manufacturing using finite element structural analyses in order to demonstrate compliance with the deflection requirements of the secondary mirror when pointing zenith and near horizon. This paper will review the optical and opto-mechanical design, fabrication, integration and alignment of the BLAST telescope.

The photoconductor detector arrays for the PACS instrument (Photoconductor Array Camera and Spectrometer) aboard the future ESA telescope Herschel have been developed during the engineering phase in 1999. In early 2000 the construction of the qualification models began for both, the highly and low stressed Ge:Ga arrays, which consist of 12 linear modules each. These two types of photoconductor arrays are dedicated for different wavelengths bands in the spectrometer section of the instrument. While the performance of a few engineering arrays has been studied and presented earlier, additional data are meanwhile available on the absolute responsivity and quantum efficiency of the detectors. Furthermore, experience has been obtained during manufacture of a larger series of arrays giving better statistics on performance aspects, such as uniformity of the cutoff wavelengths and of the responsivity or the maximum stress obtainable within such arrays. Considerable progress has also been made in the development and manufacture of the 4 Kelvin Cold Read-out Electronics (CRE), which will integrate and multiplex the signals generated in each linear array with its 16 detector pixels. Manufacture of the detector arrays for the qualification model is scheduled to be completed by this summer, and manufacture of the flight model has already started. The qualification model will be delivered to the test facilities, where absolute spectral performance of the 24 linear modules will be determined. In this paper we give a summary of the related activities and results as obtained during manufacturing and testing.

We use the HAWAII-2 (2048 × 2048 HgCdTe) FPAs in MOIRCS (Multi-Object Infra-Red Camera and Spectrograph) for the astronomical use on the Subaru telescope. MOIRCS, which is currently being constructed by Tohoku University and the National Astronomical Observatory of Japan, is one of the second generation instruments for Subaru. It will provide the wide-field imaging mode (4 × 7 arcmin²) and the multi-object spectroscopy mode with the wavelength range of 0.8 to 2.5 μm. To achieve the large field of view with the high spatial resolution, we use two large-format near-infrared arrays, HAWAII-2. We have developed an infrared array control system specially designed for flexible control and efficient data acquisition of the HAWAII-2 arrays. The array control system, TUFPAC, consists of a personal computer operated by LINUX OS and commercially available DSP boards. By using TUFPAC and the cryostat for array tests, we have made tests of the HAWAII-2 array. In this paper, we report on our array control system and the results of various performance tests for the HAWAII-2 array.

I present, apparently, a new description of radiative transfer problems in the time domain. It appears that for the first time a simple physical picture emerges of the underlying essence of scattered radiance when dealing with isotropic axially-symmetric scattering in nonconservative linear media as attenuated travelling waves was by analogy. The method used a new differential equation approach. Initially its accuracy in the frequency domain was demonstrated by applying it to a solved problem, where in the literature it is dealt with using the conventional 95-year-old integro-differential equation description. Confidence in the differential equation method was bolstered by showing how this new method produces the same analytical answer. The new technique converts the integro-differential equation formulation of radiative transfer into a “pure” differential equation formulation, consisting here in a mixture of ordinary and partial derivatives, and solves that. This paper analyzes the situation in the time domain using the differential equation description and again yields a travelling wave description. However, this time it is not simply by analogy that such a description is obtained. It is exact. This result of attenuated travelling waves was demonstrated in a prior paper by solving the integro-differential equation for the classic problem of axially-symmetric scalar isotropic scattering in a nonconservative linear medium. In this paper we revisit the problem, this time solving it by the differential equation method and obtain the identical result, once again confirming the method.

We analyze and predict the performance of a fiber optic temperature sensor from the measured fluorescence spectrum in order to optimize its design. We apply this analysis to the erbium-doped silica fiber employing the power ratio technique. We develop the expressions for the signal-to-noise ratio in the band to optimize the sensor performance in each spectral channel. We improve the signal-to-noise ratio by a factor of five for each channel, compared to earlier results. We evaluate the analytical expression for the sensor sensitivity and predict it to be about 0.02 K^-1 for the temperature interval from room temperature to above 200 C, increasing from 0.01 K^-1 at the edges of the interval to 0.03 K^-1 at the center, at 100-130 C. The sensitivity again increases at temperatures higher than 300 C, delineating its useful temperature intervals.

A NIST-developed pyroelectric radiometer was characterized and calibrated to extend the NIST high accuracy spectral responsivity scale from the visible range to the ultraviolet (UV) and infrared (IR). The transmission of the gold-black coated LiNbO₃ pyroelectric material is negligibly small, therefore the absorptance, equal to 1-reflectance, is proportional to the responsivity of the detector. The spectral total reflectance of the coating was measured with integrating spheres and spectrophotometers to determine the relative spectral responsivity from the UV to the IR. The relative spectral responsivity was converted into absolute spectral power and irradiance responsivities by measuring the total power in a 442 nm stabilized laser beam. The reference device for absolute calibration was a Si trap-detector calibrated against the primary standard cryogenic radiometer. The calibrations were repeated with 31 months separation. A 0.3 % long-term shift in the reflectance was measured between 800 nm and 19 μm. The 28 % reflectance at 10.6 μm scaled up the 0.1 % spatial responsivity non-uniformity in the visible (where the reflectance was 0.4 %) to 8 %. The spectral power and irradiance responsivity scales of the pyroelectric radiometer have been realized between 250 nm and 2.5 μm with a relative standard uncertainty of less than 0.34 % (coverage factor k=1).

The large variety of high-precision unique blackbody sources: those operating at fixed temperatures provided by phase transitions of metals and metal-carbon eutectics, and variable-temperature ones had been designed in VNIIOFI for high-precision radiometry, radiation thermometry and spaceborne remote sensing within a 100 to 3500K temperature range. Paper reviews the blackbodies (BBs) ranged to low, middle and high temperatures, and describes spectral radiance and irradiance calibration facilities on the base of these BBs in IR and V-UV spectral ranges. The latest investigations of high-temperature fix-points based on metal-carbon eutectics Re-C (2748K) demonstrated an excellent reproducibility of freezing plateau (up to 0.01% in terms of radiation temperature) between series of measurements/crucibles, and about 0.003% within a sample measurement session, i.e. better than 100mK. Further Re-C (spectral irradiance measurements) and TiC-C (3057° C) eutectics are being investigated for use as high-stable radiance/irradiance sources above the conventionally assigned values of temperatures of ITS-90.

The concept for a new high spatial resolution, high-temperature, Dynamic Infrared Scene Projector (DISP) for generating high-speed (microsecond range) broadband (3-16 microns) IR scenery through visible pumping of DISP semiconductor scene (visible-to-infrared conversion) was developed, fabricated and tested. The principle of this new device operation and the results of our initial experimental study are reported for the first time. Key potential operating parameters of the new device prototype (based on a Germanium screen) are compared to that of modern conventional DISP engine (SBIR Emitter Array Projector).

In the CrIS Acceptance Test Program two of the most important sets of requirements to verify are the spatial and spectral requirements of the sensor. The development of the test program to verify these requirements starts with the understanding of the system level requirements and how they are allocated to the sensor and module levels. Knowing the requirements and the verification method, the test developer selects the most appropriate test methodology to verify each requirement form the list of test concepts that were proposed. For the chosen concept the developer derives the requirements for the test and test equipment needed to verify the system requirements. The collimator serves as an example of the flowdown of system requirements for the spatial and spectral uncertainties to test requirements and test performance data on the collimator are reviewed. Models and simulations are also key tools for developing the tests. Examples of models used for the spatial spectral requirements are an ILS model, a gas absorption model and an edge response model. This paper serves as a summary of the processes used and requirements needed to develop the characterizations for the CrIS sensor.

The Cross-track Infrared Sounder (CrIS) is part of the National Polar-orbiting Operational Environmental Satellite System (NPOESS) series of polar-orbiting spacecrafts. The CrIS sensor forms a key component of the larger Cross-track Infrared/Microwave Sounding Suite (CrIMSS) and is intended to operate within the context of the CrIMSS architecture. The CrIS instrument is a Michelson interferometer infrared sounder covering the spectral range of approximately 3.9 to 15.4 microns. CrIS provides cross-track measurements of scene radiance to allow the calculation of temperature and moisture vertical distributions in the Earth's atmosphere. We present sensor data record (SDR) level 1B algorithms that are needed on ground in order to produce meaningful data meeting all requirements of the NPOESS CrIS instrument. Level 1B data are made of geolocated, radiometrically and spectrally (spatial frequency) calibrated spectra with annotated quality indicators. CrIS SDR algorithms include, among others, radiometric calibration with phase error correction, interferometer fringe count error handling and correction of the instrument line shape (ILS) distortion.

The GOME-2 spaceborne spectrometers will provide data for the ozone product chain of the EUMETSAT Polar System (EPS), in charge of the monitoring of atmospheric ozone. The accuracy of any geophysical parameter retrieved from the GOME-2 measurements will ultimately be limited by the accuracy of the spectral and radiometric calibration of instrument data. This imposes strong accuracy and stability requirements on the instrument, the calibration activities and the ground processing. In this paper, the processing scheme for the spectral and radiometric calibration of GOME-2 data is presented.

The Solar Occultation FTS for Inclined-orbit Satellite (SOFIS) is a solar occultation Fourier transform spectrometer (FTS), developed by the Ministry of the Environment (MOE) of Japan, that will be onboard the Global Change Observation Mission-A1 (GCOM-A1) satellite. GCOM-A1 will be placed in a 650km non-sun-synchronous orbit, with an inclination angle of 68 deg. SOFIS is the successor of ILAS-II, which will be onboard the Advanced Earth Observing Satellite-II (ADEOS-II). SOFIS measures atmospheric constituent vertical profiles with 0.24 cm^-1 spectral resolution in 3-13 μm and 1 km vertical resolution. SOFIS will measure the global distribution of O₃, HNO₃, NO₂, N₂O, CH₄, H₂O, CO₂, CFC-11, CFC-12, CIONO₂, aerosol extinction, atmospheric pressure, and temperature. SOFIS uses a double-pass dual-pendulum type FTS with diode laser sampling system to reduce the size and weight. Two photo-voltaic (PV) MCT (HgCdTe) detectors and a pulse-tube cooler will achieve high linearity and low-noise performance. In addition, it has a visible (O₂, A band) grating spectrometer for pressure and temperature retrieval and a sun-edge sensor for the tangent height position detection. We present the test results of FTS and detector assembly engineering model and describe the SOFIS/FTS calibration system.

Cosmic material enters the Earth's atmosphere daily. These incoming meteoroids are vaporized during atmospheric entry, and the resulting vapor condenses into "smoke" particles which accumulate near 85 km altitude. Cosmic particles are thought to be important in the formation of polar mesospheric clouds, which have been identified as the "miner's canary" of climate change. This work addresses some issues associated with remote measurements of the smoke layer. Signals expected from cosmic particles were modeled and these results indicate that the recently proposed Solar Occultation for Ice (SOFIE) instrument may have the capability to provide the first remote measurements of the smoke layer.

Accurate high resolution temperature sounding through our atmosphere is paramount to improving our weather forecasting, monitoring, and analysis capability. From the vantagepoint of earth Orbit, remote temperature sounding is becoming a reality and its accuracy is bolstered by recent advances in infrared hyper-spectral sensor capability. One promising approach takes advantage of a two-dimensional, imaging Fourier transform spectrometer to obtain a data cube with the field of view along one plane and multiple IR spectra (one for every FPA pixel) along the orthogonal axis. The spatial resolution is limited only by the pixel pitch in the imaging focal plane and the optics used to collect the data. The maximum optical path difference in the Michelson FTS defines the spectral resolution and dictates the number of path-length interferogram samples (FPA frames required per cube. This paper discusses the unique challenges placed on the focal plane by the Geosynchronous Imaging Fourier Transform Spectrometer (GIFTS) approach and how advanced focal plane technology is applied to satisfy these challenges. Two focal planes are required to provide spectral coverage from 4.4 to 6.1um and 8.85-14.6um. Currently, the GIFT’s LWIR focal plane is the longest wavelength two-dimensional PV HgCdTe array of this size (128 square on 60 um centers) planned for space deployment. The paper presents performance data of Liquid Phase Epitaxy (LPE) fabricated HgCdTe detectors and design details of the advanced readout integrated circuit necessary to meet the demanding requirements of the imaging sensor for the GIFTS instrument.

Focal plane arrays used for remote sensing applications are required to operate at high temperatures and are subject to high terrestrial background fluxes. Typical remote sensing applications like cloud/weather imagery, sea-surface temperature measurements, ocean color characterization, and land-surface vegetation indices also require FPA's that operate from the visible through the LWIR portion of the spectrum. This combination of harsh requirements have driven the design of a unique LWIR FPA, that operates at 80K under 300K background conditions, with an operating spectral range from 11.5μm to 12.5μm, and a spectral cutoff of 13.5μm. The FPA consists of 2 side by side arrays of 1×60 HgCdTe, (grown by molecular beam epitaxy) photovoltaic, detector arrays bump bonded to a custom CMOS Si readout. The 2 arrays are completely independent, and can be operated as such. The readout unit cell uses two, current-mode, analog building blocks; a Current Conveyor (CC1) and a dynamic current mirror. The CC1 has input impedance below 300 Ω and an injection efficiency that is independent of the detector characteristics. This combination extracts high performance and excellent sensitivity from detectors whose average RoA values are approximately 1.7 Ω-cm² at T=80K. The dynamic current mirror is used to subtract high background photocurrent while preserving excellent dynamic range. In addition to the performance enhancing readout, the detectors are manufactured with integral microlenses and operated in reverse bias to take advantage of their increased dynamic impedance. The dark currents associated with reverse bias operation are subtracted along with the background photocurrents by the dynamic current mirror. Analysis of this unique ROIC architecture will be presented along with modeled performance. Measurements were performed on a LWIR FPA. Expected and measured FPA results are shown in the table below. The expected data are calculated from FPA models and compared to the measured values.

MOSAD(copyright), Multiplexed OverSample Analog to Digital conversion, is a low power on focal plane analog to digital, A/D, process that places an oversample A/D at each pixel site. Two full custom designs for a visible light staring array were developed with this approach. One design approach uses a silicon photo diode in combination with photo gates at the pixel and the other approach uses an all photo gate sensor for detection. Both arrays were designed with a 320x240 format with the pixels placed on 16 micron centers. The system includes the camera assembly, driver interface assembly, a frame grabber board with integrated decimator and Windows 2000 compatible software for real time image display. The camera includes the sensor, either photo gate or photo diode, mounted on a PC card with support electronics. A custom lens mount attaches the camera to C or CS mount lens. Testing was done with a Tamron 13VM2812 CCTV CS mount lens. Both an RS644 and an RS422 parallel interface card assembly was developed to attach to the frame grabber board. The final iteration cameras were tested at the Amain facility and pictures were taken. At 400 samples per second, measured on chip power consumption is under 10 milliwatts. Noise measurements at sample rates from 400 samples per second to 1,600 samples per second were taken for both parts. The photo diode worked and produced images but it had a sense amplifier problem that prevented adequate noise measurement. At 28 times oversample, the photo gate achieved typical 9 to 11 bits signal to noise with best case measured at 13 bits. Nonuniformity variation was below the noise floor.

Understanding Earth's climate, atmospheric transport mechanisms, and the hydrologic cycle requires a precise knowledge of global atmospheric circulation, temperature profiles, and water vapor distribution. The accuracy of advanced sounders such as AIRS/AMSU/HSB on NASA's Aqua spacecraft can match radiosonde accuracy. It is essential to fold those capabilities fully into the NPOESS, enabling soundings of radiosonde accuracy every 6 hours around the globe on an operational basis. However, the size, mass, power demands, and thermal characteristics of the Aqua sounding instrument suite cannot be accommodated on the NPOESS spacecraft. AIRS-Light is an instrument concept, developed under the Instrument Incubator Program, which provides IR sounding performance identical to the AIRS instrument but uses advances in HgCdTe FPA technology and pulse tube cooler technology, as well as design changes, to dramatically reduce the size, mass, and power demand, allowing AIRS-Light to meet all NPOESS spacecraft interface requirements. The AIRS-Light Instrument Incubator program fostered the development of photovoltaic-mode HgCdTe detector array technology for the 13.5-15.4 μm band covered by photoconductive-mode HgCdTe arrays in AIRS, achieved state of the art results in this band, and substantially reduced the development risk for this last new technology needed for AIRS-Light implementation.

The Oxygen A-band spectrometer breadboard was developed to demonstrate alignment and focus methodologies planned for the spectrometers to be used for the Orbiting Carbon Observatory (OCO). The OCO is a proposed Earth System Science Pathfinder (ESSP) mission to provide the first global CO₂ measurements from space with a relative accuracy of 1-ppm on scales of 2.5 × 10⁵ km². The flight system uses three refractive spectrometers to measure column CO₂ at 1.58 and 2.06-micrometers and column O₂ in the oxygen A-band at 0.76 micrometers. This paper describes a relatively fast, f/2, high resolution grating spectrometer breadboard designed, manufactured, and tested in less than 6 months. The breadboard successfully validates the optical design and alignment approach to be used for the three spectrometers that comprise the OCO instrument.

It has been found that a close relationship exists between the spectral reflectance and the health as well as the productivity of soybean canopies. Basing on this property, a remote sensing method was used to assess the plant productivity and health, which was able to cover a large area simultaneously. In this project, aerial images and reflectance measurements were obtained from two soybean fields located in Story Country, Iowa during summer 2000 and 2001. Aerial image were taken on both infrared band and color band. An eight-band radiometer was used to obtain the reflectance reading at ground level, which ranged from 460-nm to 810-nm. A study on aerial-radiometer data relation for two continuous years was carried out. The reflectance measurement from radiometer served as ground truth. Also, the calibration procedure for aerial image was applied. Because the atmospheric distortion became more pronounced when the aerial image was taken at higher altitude. Scattering and absorption will affect the image intensity which indirectly affect our analysis. The red, green and blue ground cloths were put beside the fields when the aerial image was taken. They are used as references to evaluate color distortion in the red, blue and green bands respectively.

We analyze the polarization changes introduced by a rotated Dove prism on the linearly polarized light, using the Jones calculus. The state of polarization changes from the linear to a mildly elliptical one when a plane wave front passes through a rotated Dove prism: its semi-mayor axis is nearly parallel to the input plane of polarization, for any angle of rotation. The interferogram contrast remains high for all shearing angles in spite of polarization changes when the Dove prism is incorporated into a rotational shearing interferometer. These results are confirmed experimentally.

An analytical expression is derived for the tilt introduced into a wave front by a Dove prism with manufacturing errors: error in the base angles and in the pyramidal angle. We found that the tilt decreases when the base angles are increased above the values of traditional design. The increase in the length-aperture ratio of a prism is detrimental to its performance. However, a Dove prism with a widened aperture increases throughput and keeps prism weight manageable for implementation in the rotational shearing interferometer. Thus, we propose a Dove prism designed with a widened aperture to increase throughput in the rotational shearing interferometer and with larger base angles to minimize the wave-front tilt introduced due to manufacturing errors.

We use the point spread function and the modulation transfer function as two measures to evaluate the performance of the multi-aperture interferometric configurations for the detection of faint planets in the vicinity of bright stars. We design non-redundant interferometric layouts that provide satisfactory coverage of the spatial frequencies of interest. We propose a design incorporating a rotating, rotationally shearing interferometer and compare its performance with the Earth-based, fixed, linear configurations.

We propose to use the rare-earth-doped silica as the IR-to-visible converter. We describe its principle of operation employing the up-conversion upon pumping with the near IR radiation. We developed a time-dependent 3-D heat transfer model for fiber geometry with finite element method. We present results of the study to determine spatial and temporal resolution of this transducer for the constant and impulse irradiation profile. We conclude that better temporal and spatial resolution is achieved when the fiber is in contact with a cold reservoir. The cold sink also assists in the rapid response of the device, as the latent image is quickly erased.

We have constructed a far infrared detector array consisting of a 1×16 Ge:Ga and a 1×16 Ge:Sb placed side-by-side to form a linear, 1×32 array. An SBRC-190 readout multiplexer, which is a 1×32, multi-gain, capacitive transimpedance amplifier (CTIA) manufactured by Raytheon Infrared Operation, is wire bonded to the array. The array has been tested in the temperature range of 3.2K to 2.6K under various infrared radiation levels. In this presentation we will discuss the design and will report on the results of the preliminary tests conducted on this array at 3.0K. This developmental effort is intended to test the viability of the SBRC-190 unit-cell design for far infrared detector arrays and help foster improvement and further development of readout electronics based on the CTIA design. In addition, we hope to extend the detector design and develop a two-dimensional, monolithic array.

The structure and dynamic properties of achiral polar smectic liquid crystals formed by bow shaped molecules is considered and described by two two-dimensional order parameters, &vec;P and &vec;ξ. The first, polarization order parameter, gives the average projection of the arrow vectors on the smectic layer planes. The second, tilt order parameter, gives the average magnitude and direction of the tilt. To study the possible liquid crystal structures and their properties, a discrete phenomenological model taking into account the competing interactions between the nearest-neighbor smectic layers is used. The free energy of the system is expressed as a sum over smectic layers with terms modeling the appropriate intralayer and interlayer interactions and written only in terms of the arrow and the string order parameters. The free energy is then minimized in order to obtain stable structures and deduce their optical properties. There exist solutions for the case of strong coupling between the polarization and the tilt order parameters arising from attractive intralayer van der Waals and from steric interactions. In this contribution, we focus our attention to the case of weak coupling between the two order parameters and investigate possible structures and related optical properties of the system.