This PDF file contains the front matter associated with SPIE Proceedings Volume 8154, including the Title Page, Copyright information, Table of Contents, and the Conference Committee listing.

The structure of planetary surfaces unveils basic formation processes and evolution lines of different objects in the solar system, and often the view on the top of a planet is the only available information about it. Advanced remote sensing technologies on deep space missions are aimed at accessing a maximum of relevant data to characterize a planetary object holistically. This approach requires concert strategies in planetary and engineering science. In this framework VIS/IR spectroscopic remote sensing methods are key technologies for imaging planetary atmospheres and surfaces, for studying their composition, texture, structure and dynamics. Basing on these analyses it succeeds to observe the single objects in more global geo-scientific content. The paper focuses on main geo-scientific output coming from spectroscopic studies of planetary surfaces in conjunction with their interiors, atmospheres, and the interplanetary space. It summarizes selected results of spectral studies onboard of the ESA deep space missions BepiColombo, Venus Express, Mars Express, and Rosetta. The corresponding spectral instruments are introduced. The complex conflation of special knowledge of the disciplines planetology, optical and IR measuring techniques, and space flight engineering is demonstrated in several examples. Finally, the paper gives an outlook of current developments for spectral studies in planned missions, and sums up some of the driving questions in planetary science.

Recent broadband observations by the SABER sensor aboard the TIMED satellite hint at intriguing new vibrationrotation excitation and loss processes that occur in the energy dissipation of the ionosphere-thermosphere as it responds to solar storms. To address the questions exposed by the SABER data, SDL's field-widened interferometer has been brought back after three decades to again fly into or above aurorally disturbed atmosphere to gain the data needed to better understand the different processes of ionosphere-thermosphere energetics. The paper discusses the evaluation and design phases (laboratory evaluation, a rocket flight, and a satellite flight) needed to prepare this elegant and unique interferometer to reach its goal of making high resolution (0.5 cm^-1) and wide bandwidth (1300- 8000 cm^-1) measurements of the ionosphere-thermosphere world-wide. Design details of interferometer will be presented along with comparisons between a standard Michelson interferometer and the field-widened sensor to illustrate just how the Bounchareine and Connes field-widened form provides the enhanced performance needed for the new missions. The paper also describes how the improved Inferometer design will leverage advances in modern electronics, detectors, bearing design and software to gain significant improvements in the performance of the upgraded field-widened interferometer-spectrometer when compared to the heritage instrument.

Many organizations, including Space Dynamics Laboratory, have built blackbodies with calculated emissivities of 0.995 to 0.9999 and estimated radiance temperature uncertainties of a few hundred mK or less. However, the calculated performance has generally not been demonstrated through testing or comparison with other highperformance blackbodies. Intercomparison is valuable; historically, when equipment or experimental results have been intercompared they are often found to disagree by more than the claimed uncertainties. Blackbody testing has been limited because testing at the required accuracy (0.1% or better in radiance) is a significant expense. Such testing becomes essential when proven, SI-traceble, absolute accuracy is required, such as for the CLARREO mission which has an absolute accuracy requirement of 0.1 K (3 sigma) at 220 K over most of the thermal infrared and needs high-performance blackbodies to support this requirement. Properly testing blackbodies requires direct measurement of emissivity and accurate measurement of radiance or comparison of radiance from two blackbodies. This presentation will discuss these testing needs, various types of testing, and test results for a CLARREO prototype blackbody.

Recent discoveries from analysis of measurements made by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on the Thermosphere-Ionosphere- Mesosphere Energetics and Dynamics (TIMED) satellite have shown that NO(v) 5.3 um emission is the primary mechanism of dissipating solar-geomagnetic storm energy in the thermosphere. Further insight into the ionosphere-thermosphere (IT) storm-time response emerged from observations and analysis of the SABER 4.3 um channel radiances, which showed that nighttime 4.3 um emission is dominated by NO⁺(v) during geomagnetically disturbed conditions. Analysis of SABER NO⁺(v) 4.3 um emission led to major advances in the understanding of E-region ion-neutral chemistry and kinetics, such as the identification of a new source of auroral 4.3 um emission, which also provides a new context for understanding auroral infrared emission from O₂(a¹▵g). Surprisingly, NO⁺(v) 4.3 um emission is the second largest contribution to solar-geomagnetic infrared radiative response and provides a non-negligible contribution to the "natural thermostat" thought to be solely due to NO(v) 5.3 um emission. Despite these major advances, a fully physics-based understanding of the two largest sources of storm-time energy dissipation in the IT system from NO(v) and NO⁺(v) is lacking because of the limited information content contained in SABER's broadband infrared channel measurements. On the other hand, detailed information on the chemical-radiative excitation and loss processes for NO(v), NO⁺(v), and O₂(a¹▵g) emission is encoded in the infrared spectrum, of which SABER only provides an integral constraint. Consequently, a prototype infrared field-wide Michelson interferometer (FWMI) is currently under development to advance the understanding of IT storm-time energetics beyond the current state of knowledge. It is anticipated that progress in the developments of the FWMI technology, along with advancements in a physics-based understanding of the fundamental chemical-radiative mechanisms responsible for IT infrared emission, will play an integral role in the future planning of a rocket-borne and satellite-based Eregion science missions. In this paper, a survey of recent SABER discoveries in IT ion-neutral coupling will be given, open questions in a physics-based understanding of chemical-radiative vibration-rotation excitation and loss from important IT infrared emitters will be identified, and the FWMI instrument requirements necessary to address these open science questions will be presented.

At NASA's Goddard Space Flight Center, we are developing the next generation laser transmitters for future remote sensing applications including a micropulse altimeter for ice-sheet monitoring, laser spectroscopic measurements and high resolution mapping of the Earth's surface as well as potential missions to other planets for trace gas measurement and mapping. In this paper we will present an overview of the spaceborne laser programs and offer insights into future spaceborne lasers for remote sensing applications.

Academic and industrial researchers require ultra-low power, compact laser based trace-gas sensor systems for the most demanding environmental and space-borne applications. Here the latest results from research projects addressing these applications will be discussed: 1) an ultra-compact CO₂ sensor based on a continuous wave quantum cascade laser, 2) an ultra-sensitive Faraday rotation spectrometer for O₂ detection, 3) a fully ruggedized compact and low-power laser spectrometer, and 4) a novel non-paraxial nonthin multipass cell. Preliminary tests and projection for performance of future sensors based on this technology is presented.

A new sensor is developed for measuring local temperatures. This sensor is based on a thermal-resistive probe and on photoluminescence of crystal. The final purpose is to develop a device calibrated in temperature and capable of acquiring images of local temperature at sub-micrometric scale. Indeed, the sensor temperature can be obtained in two distinct ways: one from the thermal probe parameters and the other from the green photoluminescence generated in the anti- Stokes mode by the Er ions directly excited by a red laser. The thermal probe is in Wollaston wire whose thermal-resistive element is in platinum/rhodium. Its temperature is estimated from the probe electrical characteristics and a modelling. A microcrystal of Cd_0.7Sr_0.3F₂: Er³⁺(4%)-Yb³⁺(6%) about 25μm in diameter is glued at the probe extremity. This luminescent material has the particularity to give an emission spectrum with intensities sensitive to small temperature variations. The crystal temperature is estimated from the intensity measurements at 522, 540 and 549 nm by taking advantage of particular optical properties due to the crystalline nature of Cd_0.7Sr_0.3F₂: Er³⁺-Yb³⁺. The temperature of probe microcrystal is then assessed as a function of electric current in the thermal probe by applying the Boltzmann's equations. The first results will be presented and discussed.

We discuss precision spectroscopy with a comb-based spectrometer at 3.4 μm. Our goal is to explore comb-based spectroscopy as an alternative method for fast, highly resolved, accurate measurements of gas line shapes. The spectrometer uses dual 1.5 μm frequency combs down converted to 3.4 μm via difference frequency generation (DFG) with a stabilized 1 μm fiber laser. One 3.4 μm comb is transmitted through methane and heterodyned against the second, offset comb to measure the gas absorption and dispersion. Doppler-broadened methane spectral lines are measured to below 1 MHz uncertainty. We also discuss the higher sensitivity alternative of a comb-assisted swept-laser DFG spectrometer.

The European Space Agency (ESA) is currently developing, in co-operation with the Japan Aerospace Exploration Agency (JAXA) the EarthCARE satellite mission with the basic objective of improving the understanding of the cloudaerosols- radiation interactions within the Earth's atmosphere. As part of the EarthCARE payload, the MSI instrument will provide images of the earth in 7 spectral bands in the visible and infrared parts of the spectrum, with a spatial ground resolution of 500 m and an image width on the ground of 150 km. The radiometric accuracy of the MSI instrument is of paramount importance to accurately retrieve the physical properties of clouds and aerosols from the radiometric measurements in the different MSI spectral channels. The prelaunch calibration campaign together with the in-flight calibration facilities that the MSI instrument incorporates will ensure the fulfilment of the radiometric requirements of the mission. The overall calibration approach for the MSI instrument is described in this paper, including the pre-launch and in-flight calibration activities.

To examine the polarimetric Bidirectional Scatter Distribution Function (BSDF) of samples in the mid-wave infrared (MWIR) and long-wave infrared (LWIR), a full Stokes polarimetric optical scatter instrument has been developed which is tunable from 4.3-9.7 microns through the use of six external-cavity quantum-cascade lasers. The polarimeter is realized through a dual-rotating-retarder configuration, which allows full Mueller-matrix extraction over the tunable wavelengths. Optical characterization of the polarimeter components was conducted to establish performance baselines for the system. The dynamic range of the system is nine orders of magnitude.

Novel nanostructured III-V semiconductor devices are investigated for light detection in the near infrared spectral region. Single-electron memories based on site-controlled InAs quantum dots embedded in a GaAs/AlGaAs quantum-wire transistor were fabricated and studied. By using a nanohole structure template on a modulation-doped GaAs/AlGaAs heterostructure, two single InAs quantum dots were centrally positioned in a quantum-wire transistor so that pronounced shifts of the transistor threshold occur by charging of the QDs with single electrons. Single-electron read and write functionalities up to room temperature were observed and the memory function can be also controlled by light with a wavelength in the telecommunication range. Furthermore, AlGaAs/GaAs/AlGaAs double barrier resonant tunneling diodes (RTD) with an embedded GaInNAs absorption layer have been fabricated for telecom wavelength light detection at room temperature. The absorption layer was lattice matched grown within the GaAs system of the RTD. We demonstrate that the devices exhibit typical RTDs characteristic and they are light sensitive at the telecom wavelength 1.3 μm in the order of just a few nW. Routes to further reduce the detection limit are discussed whereas the envisaged devices have prospects to deliver sensitivities approaching the quantum limit.

In conventional InGaAs/InP single photon avalanche detectors, zinc diffusion is used to define the multiplication junction to reduce the dark count and maximize the detection efficiency. The device performance is very sensitive to process variations, and the diffusion process must be carefully calibrated and analyzed to minimize any edge breakdown effects. Here we present a much simpler design utilizing patterned zinc diffusion rings. The processing is simplified - a single diffusion compared to two diffusions in a conventional device; and the device performance is not as critical to the processing variations. The diffusion is performed on a self-quenching self-recovering epitaxial structure, resulting in free-running single photon detection efficiencies of 20% at 140 K, with a dark count rate of 8 kHz for a 22μm diameter device.

In this paper we report improved device performance for type II superlattice (SL) photo diodes by inserting a graded AlGaSb barrier layer inserted into the depletion region of the PIN diode to suppress dark current and employing SiO₂ as a passivation layer. The I-V characteristics shows presence of AlGaSb barrier layer in the device structure increased R0A values by up to a factor of 40 times. Sidewall resistivity was increased by an order of magnitude with SiO₂ passivation. The fabricated photo diode with λ_c=12.8-μm shows peak responsivity of 3.7 A/W at 10.6 μm and Johnson noise limited peak detectivity of 1×10¹¹ cmHz^1/2/W under zero bias at 83 K under 300 K background radiation with a 2π field-of-view.

The epitaxial growth parameters optimized for mid-wavelength infrared (MWIR) InAs/GaSb superlattice (SL) growth are not directly applicable for long-wavelength infrared (LWIR) SL growth. We observed a two orders of magnitude drop in the spectral intensity of the measured photoresponse (PR) as the InAs layer thickness in the SL increases from 9 monolayers (MLs) to 16 MLs for a fixed GaSb layer thickness of 7 MLs. However, the theoretically calculated absorption strength decreases only by about a factor of two. So other factors affecting photoresponse, such as carrier mobility and lifetime, are likely responsible for the large drop in the PR of the LWIR SL in this sample set. In fact the measured Hall properties of MWIR and LWIR SLs are very different, with holes as the majority carriers in MWIR SLs and electrons as the majority carriers in LWIR SLs. Therefore we investigated the charge carrier density, carrier mobility, and carrier recombination dynamics in LWIR SL samples. Specifically we used temperature-dependent Hall effect and time-resolved pump-probe measurements to study the effect of adjusting several growth parameters on the background carrier concentrations and studied carrier lifetimes in LWIR SLs.

We report on growth and device performance of infrared photodetectors based on type II InAs/Ga(In)Sb strain layer superlattices (SLs) using the complementary barrier infrared detector (CBIRD) design. The unipolar barriers on either side of the absorber in the CBIRD design in combination with the type-II InAs/GaSb superlattice material system are expected to outperform traditional III-V LWIR imaging technologies and offer significant advantages over the conventional II-VI material based FPAs. The innovative design of CBIRDS, low defect density material growth, and robust fabrication processes have resulted in the development of high performance long wave infrared (LWIR) focal plane arrays at JPL.

Significant progress has been achieved in the antimonide-based type-II superlattices since the analysis by Smith and Mailhiot in 1987 first pointed out their advantages for infrared detection. In the long-wavelength infrared (LWIR), type-II InAs/Ga(In)Sb superlattices have been shown theoretically to have reduced Auger recombination and suppressed band-to-band tunneling. Suppressed tunneling in turn allows for higher doping in the absorber, which has led to reduced diffusion dark current. The versatility of the antimonide material system, with the availability of three different types of band offsets, provides great flexibility in device design. Heterostructure designs that make effective use of unipolar barriers have demonstrated strong reduction of generation-recombination (G-R) dark current. As a result, the dark current performance of antimonide superlattice based single element LWIR detectors is now approaching that of the state-of-the-art MCT detector. To date, the antimonide superlattices still have relatively short carrier lifetimes; this issue needs to be resolved before type-II superlattice infrared detectors can achieve their true potential. The antimonide material system has relatively good mechanical robustness when compared to II-VI materials; therefore FPAs based on type-II superlattices have potential advantages in manufacturability. Improvements in substrate quality and size, and reliable surface leakage current suppression methods, such as those based on robust surface passivation or effective use of unipolar barriers, could lead to high-performance large-format LWIR focal plane arrays.

It is well known that the varying geometrical relationships between the Sun and the Earth throughout the year affect to some degree the performance of the instruments onboard Earth orbiting satellites. Following the commissioning of MetOp-A, EUMETSAT and NOAA have continued monitoring the long term trends in in-orbit performance of AVHRR, HIRS and AMSU-A. The data acquired since the launch of the satellite has allowed studying how the yearly seasonal variations, as well as aging, have affected the instrument performance. This paper presents the evolution of the performance of the AVHRR, HIRS and AMSU-A for more than four years since the launch of the MetOp-A satellite.

This paper compares recent spatial anomaly time series of OLR (Outgoing Longwave Radiation) and OLR_CLR (Clear Sky OLR) as determined using CERES and AIRS observations over the time period September 2002 through June 2010. We find excellent agreement in OLR anomaly time series of both data sets in almost every detail, down to the 1° x 1° spatial grid point level. This extremely close agreement of OLR anomaly time series derived from observations by two different instruments implies that both sets of results must be highly stable. This agreement also validates to some extent the anomaly time series of the AIRS derived products used in the computation of the AIRS OLR product. The paper then examines anomaly time series of AIRS derived products over the extended time period September 2002 through April 2011. We show that OLR anomalies during this period are closely in phase with those of an El Niño index, and that recent global and tropical mean decreases in OLR and OLR_CLR are a result of a transition from an El Niño condition at the beginning of the data record to La Niña conditions toward the end of the data period. This relationship can be explained by temporal changes of the distribution of mid-tropospheric water vapor and cloud cover in two spatial regions that are in direct response to El Niño/La Niña activity which occurs outside these spatial regions.

Advancements in finer geometry and technology advancements in circuit design now allow placement of digital architecture on cryogenic focal planes while using less power than heritage analog designs. These advances in technology reduce the size, weight, and power of modern focal planes. In addition, the interface to the focal plane is significantly simplified and is more immune to Electromagnetic Interference (EMI). The cost of the customer's instrument after integration with the digital scanning Focal Plane Array (FPA) has been significantly reduced by placing digital architecture such as Analog to digital convertors and Low Voltage Differential Signaling (LVDS) Inputs and Outputs (I/O) on the Read Out Integrated Circuit (ROIC).

Raytheon Vision Systems (RVS) has developed a family of high performance large format infrared (IR) detector arrays whose detectors are most effective for the detection of long and very long wavelength IR energy. This paper describes the evolution of the present state of the art one mega-pixel Si: As Impurity Band Conduction (IBC) arrays toward a four mega-pixel array that is desired by the astronomy community. Raytheon's Aquarius-1k, developed in collaboration with ESO, is a 1024 × 1024 pixel high performance array with a 30 μm pitch that features high quantum efficiency IBC detectors, low noise, low dark current, and on-chip clocking for ease of operation. Since the Aquarius-1k array was designed primarily for ground-based astronomy applications, it incorporates selectable gains and a large well capacity among its other features. Raytheon, in collaboration with JAXA (Japan Aerospace Exploration Agency), is also designing a 2048 × 2048 pixel high performance array with a 25 μm pitch. This 2k × 2k readout circuit will be based on the successful design used for the on the Mid-Infrared Instrument (MIRI) aboard the James Webb Space Telescope (JWST). It will feature high quantum efficiency IBC detectors, low noise, low dark current, and on-chip clocking for ease of operation. This version will also incorporate flight qualified packaging to support space-based astronomy applications. Previous generations of RVS IBC detectors have flown on several platforms, including NASA's Spitzer Space Telescope and Japan's Akari Space Telescope.

Large format detector arrays are responsive uniformly over spectral 1-5μm wavelength range and are available with RVS' high quality HgCdTe detector epitaxial layers on large area 15 cm diameter wafers. Large wafers enable both low cost High Definition (HD) staring FPAs, as well as the ability to approach giga-pixel format detector arrays with a seamless 10cm ×10cm continuous image plane size possible. With a 15 cm diameter detector substrate it is a straightforward growth path to a 5k×5k μm pitch 25 Mega-pixel infrared focal plane array (FPA) with smaller pitches allowing even greater format along the 10cm die length. This paper describes arrays 1.5 to 4 Mega-pixel infrared HgCdTe developed by RVS for demanding higher performance applications. Performance data for both the detector and ROIC for typical SWIR and MWIR FPAs operating at 85K will be presented. This paper will provide FPA performance capability for small pitch large format HgCdTe/Si detector arrays fabricated at RVS and manufacturing readiness low cost Mega-pixel infrared FPAs for current and future wide FOV high-resolution systems.

Polarimetry sensor development has been in work for some time to determine the best use of polarimetry to differentiate between manmade objects and objects made by nature. Both MWIR and LWIR and 2-color staring Focal Plane Arrays (FPAs) and LWIR scanning FPAs have been built at Raytheon Vision Systems each with exceedingly higher performance. This paper presents polarimetric performance comparisons between staring 2562 MWIR, 2562 LWIR, 5122 LWIR/LWIR staring FPAs and scanning LWIR FPAs. LWIR polarimetry has the largest polarimetric signal level and a larger emissive polarimetric signature than MWIR which makes LWIR less dependent on sun angles. Polished angled glass and metal objects are easily detected using LWIR polarimetry. While single band 9-11 um LWIR polarimetry has advantages adding another band between 3 and 7 um improves the capability of the sensor for polarization and spectral phenomenology. In addition the 3-7 um band has improved NEDT over the 9-11 um band due to the shorter detector cutoff reducing the Noise Equivalent Degree of Linear Polarization. (NEDOLP). To gain acceptance polarimetric sensors must provide intelligence signatures that are better than existing nonpolarimetric Infrared sensors. This paper shows analysis indicating the importance of NEDOLP and Extinction ratios.

The Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) on Venus Express, after five years in a polar Venus orbit, provided an enormous amount of new data including a three-dimensional view of the atmosphere and information on global surface properties of the planet. VIRTIS is a complex imaging spectrometer that combines three unique data channels in one compact instrument. Two of the channels are committed to spectral mapping (VIRTIS-M) and a third one to high spectral resolution studies (VIRTIS-H). The paper gives an overview about the experimental goals and the instrument performance. It discusses some selected scientific results achieved by VIRTIS, among them thermal structure and properties of the lower, middle and upper atmosphere including dynamics, polar vortex, nightglows, and NLTE effects as well as surface features obtained from nightside emission measurements in the NIR atmospheric windows.

MERTIS (MErcury Radiometer and Thermal Infrared Spectrometer), scheduled for launch on board the Bepi Colombo Mercury Orbiter, will be the first mid-infrared imaging spectrometer to explore the innermost planet of the Solar System from orbit. The instrument is an advanced IR technology designed to study the surface composition, and surface temperature variations of planet Mercury. High resolution and global mid-IR spectral and temperature data obtained by MERTIS will contribute to a better understanding of Mercury's genesis and evolution. MERTIS uses an uncooled microbolometer detector array. It combines a push-broom IR grating spectrometer (TIS) with a radiometer (TIR) sharing the same optics, instrument electronics, and in-fight calibration components for a wavelength range of 7-14 and 7-40 μm, respectively. The paper summarizes the scientific objectives, observational goals, comparative laboratory spectral studies of mineral analogues, and introduces the technical overview and actual instrument development status of the experiment.

MERTIS is a miniaturized thermal infrared imaging spectrometer onboard of ESA's cornerstone mission BepiColombo to Mercury. It shall provide measurements in the spectral range from 7-14 μm with a spatial resolution of maximal 300 m and 80 spectral channels in combination with radiometric measurements in the spectral range from 7-40 μm. The instrument concept therefore integrates two detector systems sharing a common optical path consisting of mirror entrance optics and reflective Offner spectrometer. Uncooled micro-bolometer and thermopile radiometer technology are implemented for lowest power consumption. Subsequent viewing of different targets including on-board calibration sources will provide the desired performance. Special attention is spent on the fully passive thermal design in the harsh environment around Mercury. The article will provide an overview of the 3 kg - instrument design and highlight the concept of the subsystems and technologies used. The status of the development process will be reported.

MERTIS (MERcury Thermal infrared Imaging Spectrometer) is an advanced thermal infrared remote sensing instrument which is a part of the ESA mission BepiColombo to planet Mercury. Since the instrument is designed to work as in the thermal infrared range detecting radiation using an uncooled micro-bolometer matrix it is necessary to pay special attention to the development of proper scene signal extraction methods for the elimination of undesired signal portions from the measurement data - typically being achieved by subtraction of shutter images from scene images. It is shown here how the noise of the resulting difference images for different periodic measurement modes can be predicted and minimized using a theoretical model considering measurement sequences the MERTIS instrument can be driven with. The model introduced is reflecting the noise characteristics of the instrument's analog image data channel statistically so that the analog channel itself is not modeled explicitly. Nevertheless a precise noise strength prediction can be achieved. The prediction results depend both on the specific shutter open/close sequence used and a system specific spatial-temporal autocovariance function which can be easily estimated from simple image data cubes. The predictions become very precise if a proper preprocessing removing the most strong disturbing signal portions from the image datasets is done before. Being able to predict the noise strength for arbitrary measurement sequences and giving respect to the system´s physical constraints - e.g. maximum shutter speed - an optimal measurement sequence can be found giving a maximized SNR of the images of MERTIS.

The ESA deep-space mission BepiColombo to planet Mercury will contain the advanced infrared remote sensing instrument MERTIS (MErcury Radiometer and Thermal infrared Imaging Spectrometer). The mission has the goal to explore the planets inner and surface structure and its environment. With MERTIS, investigations of Mercury's surface layer within a spectral range of 7 μm to 14μm shall be conducted to specify and map Mercury's mineralogical composition with a spatial resolution of 500 m. Due to the limited mass and power budget, the used micro-bolometer detector array will only have a temperature-stabilization and will not be cooled. The performance of the instrument is estimated by the theoretical description of the signal to noise ratio and the optics including the Offner spectrometer. The expected signal to noise ratio will be in the order of 100 and is mainly dependent on the surface temperature and the wavelength. The derived theoretical models are used to execute simulations to compute the passage of the infrared radiation of a hypothetical mineralogical surface composition and surface temperature through the optical system of MERTIS. The resulting noisy spectra are used to determine spectral features of the minerals. So it is possible to evaluate the conditions which are necessary to achieve the scientific goals of MERTIS. The intent is to estimate the spectral positions of mineralogical features like the Christiansen feature. This will be difficult because of the low signal to noise ratio and the low contrast of real mineral spectra.

We present a new optical current sensor architecture, which is based on a polarimetric configuration and a control system for self-compensation of the Faraday effect taking place at the sensor head. After passing through a bulk Faraday sensor head, the light travels through the free space reaching a Faraday modulator placed some distance away from the conductor carrying the current. The first device acts a current transducer and the second one acts as a magneto-optical element operated in a closed-loop mode to compensate the angle of rotation of the polarization introduced by the sensor head. The control system operates in closed loop feedback through a simple current-driven solenoid, and this way, the optical output from the current sensor is maintained at a constant intensity. Considering that the optical and electrical parameters of the sensor head and the Faraday modulator are known, the electrical current applied to the solenoid can be measured, and thus the current flowing through the conductor can be calculated. Experimental results demonstrate the feasibility of the proposed device to measure remotely the current carried by the conductor.

Into space, stars are the most common source of light. Planets, comets and other types of rocks reflect the incoming light from near stars. It´s said that a planet is hidden when the light from the star is brighter than the reflected light from the planet. Vectorial Shearing Interferometer (VSI) is able to distinguish between the light coming from the planet and the light coming from the star, obtaining information the relative position of the planet. We present a simulated method to detect faint sources in the way of bright sources using a VSI based in the detection of the tilt of the wavefront coming from the planet.

Micro Unmanned Aerial Vehicles (MUAV) must calculate its spatial position to control the flight dynamics, which is done by Inertial Measurement Units (IMUs). MEMS Inertial sensors have made possible to reduce the size and power consumption of such units. Commonly the flight instrumentation operates independently of the main processor. This work presents an instrumentation block design, which reduces size and power consumption of the complete system of a MUAV. This is done by coupling the inertial sensors to the main processor without considering any intermediate level of processing aside. Using Real Time Operating Systems (RTOS) reduces the number of intermediate components, increasing MUAV reliability. One advantage is the possibility to control several different sensors with a single communication bus. This feature of the MEMS sensors makes a smaller and less complex MUAV design possible.

We examined old, not-well documented paintings before the process of restoration was started, to look for the presence of any invisible signatures and dates, as well as original line drawings and possible painted-over or hidden images. We connected IR LEDs in two-dimensional arrays to allow us to sample the surface of the artwork with approximately uniform illumination, but at different peak wavelengths. We describe the extended area infrared LED illumination sources as to their geometrical arrangement, and their resulting spectral, spatial, and power output characteristics. With these light sources, we were able to make invisible information available for review and critical assessment by the art historians.

Instrument self-emission and nonlinear response play important roles in satellite thermal infrared radiometers, and can affect the accuracy of Earth scene radiance retrieval if uncorrected. This paper presents a simplified self-emission model for infrared radiometers and analyzes the interrelationships between the instrument selfemission, detector nonlinearity, and calibration intercept and slope variations using MetOp-A/HIRS prelaunch characterization data. HIRS is a traditional cross-track line scanning radiometer in the infrared and visible spectrum, including 12 long wave infrared channels (669-1529cm^-1), 7 short wave infrared channels (2188- 2657cm^-1), and 1 visible channel, with beamsplitters and a rotating filter wheel assembly consisting of 20 spectral filters separates individual channels. The warm filters and other in-path components generate selfemission which becomes the majority of the total radiance falling on the detector. The pre-launch TV data allow us to evaluate the self-emission using the simplified model. It was found that the self-emission contributions at the detectors are in the range of 95% to 97%. The self-emission fluctuates with the instrument temperature and causes the variation in instrument response, including the variations of intercept and the instrument gain. The quantification of these variations provides guideline for on-orbit calibration algorithm improvement. The selfemission model is improved and its impact on MetOp-A/HIRS on-orbit calibration and Earth scene retrieval are also assessed.

The paper proposes the uniform light sources which have a form of several or multiple optically connected integrating spheres. The principal advantages of these light sources are high photometric and metrological characteristics. As a result they have good perspectives in optical radiometry and calibration of imaging systems and optical instruments. The principal field of their application is calibration of remote sensing instruments and sensitive megapixel cameras. The light source contains several (3 ... 11) primary integrating spheres of small diameters which are installed on a secondary integrating sphere of bigger diameter. The initial light sources - halogen lamps or light emitted diodes are installed inside the primary integrating spheres. These spheres are mounted on the secondary integrating sphere. The radiation comes from the primary integrating spheres to the secondary one through diaphragms which diameters can be varied. The secondary integrating sphere has an output aperture where uniform radiance emits. It is investigated the light source design with an output aperture diameter 0.2 m and 3 or 5 primary integrating spheres. It guarantees the output radiance in range from 0.01 to 1000 W/(st•m²), radiance uniformity bigger 99.5% in an output aperture, non-linearity of an output radiance control - smaller 0.1 %. The paper presents the results of theoretical and experimental research of these light sources including the techniques for radiance calculation and the recommendations for light source design. The proposed light sources can be considered as one of the best candidates for calibration of remote sensing instruments working in optical range 0.4 - 2.2 mkm. Key words: integrating sphere, light source, calibration, uniformity, radiance, remote sensing, optical instrument.

To monitor the global column concentration of carbon dioxide (CO₂) and methane (CH₄) from space, the Greenhouse gases Observing SATellite (GOSAT) was launched on January 23, 2009, and has started the operational observation. Thermal and Near Infrared Sensor for Carbon Observation- Fourier Transform Spectrometer (TANSO-FTS) has been continuously measuring CO₂ and CH₄ distributions globally every three days, and data distribution to the public started from Feb. 16, 2010. During two years operational periods, the radiometric, geometric and spectroscopic characterizations of TANSO have been continuously conducted with updating the Level-1 processing algorithm. To make a precise spectroscopic observation, correction algorithms were newly developed, demonstrated and installed on operational processing. Two major corrections are discussed. One is correction of the scan-speed instability caused by microvibration from satellite. Through the on-orbit data analysis, degrading spectroscopic accuracy caused by periodically micro-vibrations was found, and these distortion effects were compensated with applying the re-sampling technique for interferogram. The other is non-linearity correction in the electronics. In this presentation, the detail of on-orbit characteristics and the current status of Level-1procesing for TANSO will be presented.

The Infrared Grazing Angle Reflectometer (IGAR) measures the Directional Hemispherical Reflectance (DHR) of samples at infrared wavelengths and at angles close to grazing incidence. While other devices measure DHR at or near normal, IGAR makes measurements with the angle of incidence ranging from 30 to 85 degrees. IGAR is equipped with a tunable laser source, allowing DHR measurements at wavelengths from 9.2 to 10.7m. Additional lasers can be easily added, and future plans include integrating our tunable external cavity quantum cascade lasers, extending our wavelength range from 4.3 to 9.7 microns. IGAR utilizes a hemi-elliptical mirror and a five-sided pyroelectric detector to measure DHR. By using this setup, IGAR can make low noise measurements while still capturing all of the reflected light. Our future sample set includes infrared material standards such as infragold, carbon nanotubes, as well as nanostructured devices, and various layered media.

A novel approach for the measurement of strain independent of temperature is proposed. This approach is based on the fact that an applied strain on a half etched fiber Bragg grating (FBG) leads to a change in spectral area of FBG reflection. An FBG written in a fiber optic cable, which has two different clad diameters over its length, is considered for analysis. When such FBG is illuminated with a broadband source, strain applied on the same can be estimated by measuring the changes in optical power of the reflected radiation using a photodiode. Temperature changes leads to a shift in the entire reflection, keeping the spectral area unaltered, hence allowing one to measure strain independent of temperature.