This PDF file contains the front matter associated with SPIE Proceedings Volume 10766, including the Title Page, Copyright information, Table of Contents, Author and Conference Committee lists.

The effects of lattice point defects on the absorption of incident photons in a single-quantum-well system are investigated by using a quantum-statistical theory. Our self-consistent theoretical model includes the defect-induced vertex correction to an unscreened dynamical polarization function of doped electrons under the ladder approximation. Meanwhile, the intralayer dynamical screening to the Coulomb interaction between charged point defects and conduction electrons are also taken into account within the random-phase approximation. The numerical results for nonlinear variations in absorption spectra by defects are demonstrated and analyzed for various defect densities. The combination of the current theory with a space-weather forecast model will enable novel designs of satellite onboard electronic and optoelectronic devices with radiation-hardening protection and extended lifetimes. More specifically, this theory facilitates a better characterization of photodetectors not only for high quantum efficiency and low dark current density but also for radiation tolerance or mitigation of radiation damage.

Large-scale molecular dynamics (MD) simulations, along with bond-order interatomic potentials, have been employed to study defect production, clustering and their evolution within high energy displacement cascades in semiconductors. Based on the MD results, the damage density within a cascade core is evaluated, and used to describe a new energy partition function. In addition, we have further developed a model to determine the non-ionizing energy loss (NIEL) for semiconductors, which can be used to predict the displacement damage degradation induced by space radiation on electronic components. The atomic-level based NIEL model has been applied to GaAs and GaN. At low energies, the most surviving defects are single interstitials and vacancies, and only 20% of the interstitial population is contained in clusters in GaAs, but a direct-impact amorphization in GaAs occurs with a high degree of probability during the cascade lifetime for Ga PKAs (primary knock-on atoms) with energies higher than 2 keV. However, a large number of atoms will be displaced during the collisional phase with a compacted cascade volume in GaN, and consequently, a great number of displaced atoms recombine significantly with vacancies at the same time, i.e., a pseudo-metallic behavior (PMB). This leads to the result that the majority of surviving defects are just single interstitials or vacancies for all recoil energies considered with only a small number of defects forming clusters. The total number of defects simulated in GaN can be very well predicted by the simplied Norgett, Robison and Torrens (NRT) formula due to the PMB, in contrast to GaAs where the defect number becomes much larger than the NRT value. The calculated NIEL in GaN is often found smaller than that predicted by a model based on the simple Kinchin-Pease formula. The comparisons of defect creation, density and effective NIEL in GaN to those of GaAs suggest that GaN may be much more resistant to displacement damage than GaAs, and therefore, very suitable for use in high-power space-energy systems and space-probe applications.

We recently proposed a resonator structure to increase the quantum efficiency (QE) of a quantum well infrared photodetector (QWIP). In this detector systematic parameter study, we have selected two active layer thicknesses, three detector sizes, and three doping levels to investigate the Resonator-QWIP characteristics and the EM modeling in a wide range of detector parameters. To achieve the expected performances, the detector geometry must be produced in precise specification. In particular, the height of the diffractive elements (DE) and the thickness of the active resonator must be uniformly and accurately realized to within 0.05 μm accuracy and the substrates of the detectors have to be removed totally to prevent the escape of unabsorbed light in the detectors. To attain these specifications, two optimized inductively coupled plasma (ICP) etching processes are developed to fabricate a number of test detectors. Due to submicron detector feature sizes and overlay tolerance, we use an ASML stepper instead of a contact mask aligner to pattern wafers. The highest QE we found in this study is 64% obtained from a less optimized 30 μm pitch detector with 1.0×10¹⁸ cm^-3 doping. In generally, the experimental result agrees with the prediction from electromagnetic (EM) modeling, and the R-QWIPs are able to maintain a relatively constant QE as the pixel size shrinks to 6 μm. The present 6 μm pitch R-QWIP FPA can potentially achieve 20 mK NETD at F/1.2 and 12 ms integration time.

Microbolometers are the dominant technology for uncooled thermal imaging and recently devices based on a direct birefringence measurement of a 1 μm-thick liquid crystal (LC) transducer pixel have been shown to have comparable sensitivity to current microbolometers. A modified approach for increasing device sensitivity to the temperature-dependent indices of refeaction is use of an LC resonant cavity in an etalon structure. The measured quantity is the transmission of a visible wavelength through the etalon which requires no thermal contact with the IR absorbing cavity. In this paper a detailed device design is proposed for a LC resonant cavity between dielectric mirrors. The dielectric mirror materials beneath the cavity were chosen to be compatible with existing VLSI processing. The mirror materials above the cavity were chosen to have high transmittance for the 8-14 μm LWIR band and the visible probe wavelength. The performance of this design was evaluated numerically and is shown to yield 31% change in transmitted intensity over the 200 mK temperature range considered when pixel thickness is 470 nm. For comparison, a 1 μm-thick LC pixel based on direct birefringence measurement is expected to yield a 1.6% transmission change over the same range. The etalon device represents a 19x increase in sensitivity with thinner pixels – this leads to lower pixel thermal mass and faster thermal response times.

An InAsSb/AlSb heterostructure photovoltaic detector structures were grown on a (100) semi-insulating GaAs substrates by a molecular beam epitaxy. We compare the performance of two detectors with a different type of absorbing layers, denoted p⁺B_ppB_pn⁺ and p⁺B_pnn⁺. InAs_0.81Sb_0.19 absorption layers allow for a operation up to 5.3 μm cut-off wavelengths at 230 K. p⁺B_pnn⁺ detector (n-type absorber) exhibits diffusion-limited dark currents above 200 K. AlSb barrier provides a low values of dark currents and allows a suppression of surface leakage current. With a value of 0.13 A/cm² at 230 K, the current is less than an order of magnitude larger than those determined by the "Rule 07" for HgCdTe detectors. Dark currents of p⁺B_ppB_pN⁺ detector (p-type absorber) are much higher due to a contribution of Shockley-Read-Hall mechanisms. On the other hand, device with a p-type absorber shows highest values of current responsivity, up to 2.5 A/W, point out that there is a trade-off between dark current performance and quantum efficiency.

In recent years there has been a rapidly increasing demand for energy-efficient and cost effective gas sensors. Of particular interest are CO2 sensors that can find numerous applications in health monitoring, control of air quality and horticulture. A major hurdle comes from the fact that the main CO2 absorption band lies above 4um, where very few cheap and compact sources are commercially available. Amongst the various approaches explored, the indium antimonide material system stands out as a very effective solution for the development of compact Light Emitting Diodes (LEDs). In particular, the quaternary compound AlGaInSb shows great promise as it offers a bandgap type-I alignment, which enables the design of effective multi-quantum well (MQW) active regions. In this paper we show the great potential of LED structures with strained GaInSb MQWs and AlGaInSb barriers for the next generation of mid-IR emitters at 4.3 um. Different quantum well and barrier compositions were examined through k.p simulations to extract momentum matrix elements and energy levels. The simulations were also used to assess the impact of strain and quantum well width on the efficiency of the radiative transition and to optimise the profile of the carrier injection. Based on the theoretical analysis, a number of different epilayer structures were grown by molecular beam epitaxy and the performance of LEDs with varying geometries were compared. Results confirm that strained MQW structures suppress unwanted transitions by at least one order of magnitude and provide a substantial enhancement in the internal quantum efficiency of the LEDs.

Electro-optical detection in ultraviolet (UV) and near-infrared (NIR) bands has distinct advantages for various applications. UV/NIR wavelengths are desired for a variety of NASA, defense and commercial applications. While UV and NIR detection technologies are governed by similar physical principles, a major differentiating factor lies in the choice of detector materials. Using the GaN/AlGaN material system, we are developing avalanche photodiodes (APDs) as discrete devices with high gains and responsivities. These devices, based on high crystalline quality metal organic chemical vapor deposition (MOCVD) growth on lattice-matched GaN substrates, demonstrate uniform and reliable distribution of breakdown voltage and leakage currents with gains of above 10⁶. For NIR detection we have employed epitaxial layer deposition of germanium on silicon for room temperature operation. This development is focused on demonstrating very low noise performance as a result of low dislocation densities and dark currents. Both these material/device technologies can be adapted to create arrays of detectors for a variety of applications. The primary objective in developing these sensing and imaging technologies is to advance the state-of-the-art to benefit diverse UV/NIR applications for NASA, defense, and commercial applications.

We report the deposition and characterization of 𝐴𝑙_𝑥𝑁_𝑦 thin films to use them as pyroelectric detector. 𝐴𝑙_𝑥𝑁_𝑦 thin films were deposited using a direct current (DC) magnetron sputtering from an Al target with varying concentrations of Ar:N2 at constant pressure and substrate temperature. The film thickness' were varied between 100-200 nm with varying atomic composition based on Ar:N₂ during deposition. The nitrogen content in the films varied from 39.0% to 44.7% as found by energy dispersive spectroscopy (EDS). Each of the thin films was annealed at a different temperature between 400 to 800 °C with 100 °C increment in N₂ environment and X-ray diffraction (XRD) was performed to analyze the annealed films crystallinity. From the XRD data and by using Scherrer equation, we found that for samples annealed at 600 °C for fifteen minutes has the grain size of 12.28 nm. Optical properties of the films were measured with varying wavelengths which include transmission, reflection, absorption, refraction coefficient, extinction coefficient and the optical bandgap. We also determined the electrical properties of thin films’ which include the pyroelectric coefficient, pyroelectric current, dielectric constant, and film permittivity between the temperature range 270 K to 310 K. As the temperature is increased, the pyroelectric coefficient also increased almost linearly. The pyroelectric coefficient of annealed 𝐴𝑙_𝑥𝑁_𝑦 films found to be varied between 4.86 × 10^-5 C/m²K to 1.32 × 10^-4 C/m²K. The optical transmittance through the as grown non-annealed thin films was found to be varied between 35 to 78%, while the reflectance was found to be below 25%. Because of low absorption in the thin films the extinction coefficient was found to be near zero. The refractive index was varied between 1.7 and 2.2 for the 𝐴𝑙_𝑥𝑁_𝑦 thin films. The optical bandgap was found to be 1.40 eV for non-annealed 𝐴𝑙_𝑥𝑁_𝑦 thin film which was deposited on cover glass. The dielectric constant was varied between 30-1200000 depending on the annealing temperature of the film, while the film permittivity ranges between 0-1.25×10^-5 F/m.

High Density Vertically Integrated Photodiodes (HDVIP) MWIR detectors were fabricated in LPE-grown Mercury Cadmium Telluride material. Devices were fabricated with two different acceptor level concentrations. The low doped n-region was held at a single concentration but the dimensions are tailored to simultaneously maintain high quantum efficiency while minimizing dark current and 1/f noise. Since this study target was for operating at high temperatures, detector I-V data was collected between 120 K and 280 K for I-Vs and 180 to 280 K for noise to understand current mechanisms that limit device performance at these elevated temperatures. Noise as a function of frequency has also been collected over the same temperature range. 1/f noise has also been modeled for MWIR detectors as a function of temperature and will be covered.

We present the incorporation into the chalcogenide glasses of two-dimensional periodic nanopatterns to realize the first of a kind chalcogenide-based planar optical mid-infrared tunable resonant structure. Chalcogenide (ChG) glasses are promising for infrared photonics owing to their transparency in visible to far infrared, where various biomolecules and gases have their characteristic absorption lines, arising from rotational-vibrational transitions. The region of the electromagnetic spectrum in which this absorption occurs, the amount of absorption, and the specific characteristics of the absorption curve are unique to each gas. Thus, gases can be fingerprinted using their absorption characteristics. Utilizing the mid-IR resonance feature of our nanopatterned ChG glass, an innovative approach is proposed to achieve selective gas sensing through the tuning of the sensor resonance, providing an inbuilt selectivity. As an illustration, the presented chalcogenide-based nanostructure is customized to match its resonance wavelength with the absorption band of gaseous methanol, a key plant health indicator. The highly concentrated electromagnetic field at the nanostructure surface allows highly sensitive detection of the target analyte methanol.

Higher operating temperatures can be provided by a system based on HgCdTe infrared detectors utilizing optimized material parameters (i.e. doping and defects) and non-equilibrium device architectures that suppress detector diffusion current. A PIN (P+/Intrinsic/N+) hetero-junction photodiode can eliminate Auger generated diffusion current, resulting in a diode dominated by Shockley-Read-Hall (SRH) depletion current. The limiting dark current in the PIN diode will be determined by the SRH lifetime of the HgCdTe material. We are optimizing processes for material growth and post-annealing, to improve in SRH lifetimes and hence depletion dark current and performance at higher operating temperatures. We report on the growth of high-quality n-type long wavelength infrared (LWIR) HgCdTe (cutoff wavelength 10 μm at 77 K) layers grown on CdTe/Si and CdZnTe substrates by molecular beam epitaxy (MBE). A low indium concentration in the absorber layer of ~1x10-14 is confirmed by secondary ion mass spectrometry (SIMS). In order to reduce potential SRH centers and enable low doping levels, we are applying gettering processes to reduce impurity levels below what is achievable by best practices in MBE growth. Concentration profiles of impurities such as Na and K are seen to getter to top surface and interface with the substrate, and are seen to be dramatically reduced in the absorber layer as annealing temperature is increased. We are also studying the effect of anneals on the sharpness of heterojunctions created by MBE growth. The potential benefits of heterojunction devices in suppressing dark current, particularly structures with lower thickness, can only be realized if interdiffusion can be controlled. We have successfully fit SIMS Cd profiles to a model that incorporates the temperature and composition dependence of the interdiffusion coefficient. These results, along with dependence of As diffusion coefficients vs. temperature and Hg pressure lead us to propose and test alternative annealing profiles that better preserve the heterojunctions while maintaining an appropriate amount of As diffusion for junction formation.

We report on the development of short wave infrared (SWIR) imaging arrays for astronomy and space observation in Europe. LETI and Sofradir demonstrated 640×480 SWIR HgCdTe (MCT) arrays geared at low flux, low dark noise operation. Currently, we are developing 2048×2048 arrays mated to a newly developed ROIC. In parallel, the European Space Agency and the European Commission are funding the development and industrialization of 4" CdZnTe substrates and HgCdTe epitaxy. These large wafers are needed to achieve the necessary economies of scale and address the need for even larger arrays. HgCdTe SWIR detector performance at LETI/Sofradir is known from previous programs and will be discussed here. However, we will only be able to summarize the features and specifications of the new 2048×2048 detectors which are still at a prototype stage.

Infrared (IR) technology plays a critical role in a wide range of terrestrial and space applications. IR sensing technologies and systems operating from the near-infrared (NIR) to long-wave infrared (LWIR) spectra are being developed for a variety of defense and commercial system applications. However, the performance of IR systems can be significantly limited by signal losses due to reflections from the IR substrates. Optical coatings with high antireflection (AR) characteristics can overcome this limitation and yield substantial enhancement in IR system performance. Magnolia is actively working on the development and advancement of ultrahigh performance AR coatings for a wide variety of defense and commercial applications. These nanostructured AR coatings have been demonstrated for ultraviolet (UV) to LWIR spectral bands on various substrates. The AR coatings enhance the transmission of light through optical components and devices by significantly minimizing reflection losses, providing substantial improvement over conventional thin film AR coating technologies. Nanostructured AR coatings have been fabricated using a tunable self-assembly process on substrates transparent for a given spectra of interest ranging from the UV to LWIR. The nanostructured multilayer coatings have been designed, developed and optimized for various optoelectronic applications. The optical properties of AR-coated optical and IR components and sensor substrates have been measured and fine-tuned to achieve a high level of performance. In this paper, we review our latest work focusing on high quality nanostructure-based AR coatings, including recent efforts to develop of the nanostructured coatings on IR-transparent substrates.

High performance short-wavelength infrared (SWIR) HgCdTe focal plane arrays (FPAs) of 320x256/30μm have been well developed and are now in production at Teledyne Judson Technologies (TJT). These FPAs have two cutoff wavelengths, 2.5μm and 2.9μm in general, and can operate over a wide temperature range. The detector arrays were fabricated primarily with molecular beam epitaxy (MBE) HgCdTe materials, although liquid phase epitaxy (LPE) materials were also used, both materials on CdZnTe substrates. These FPAs use ISC 9809 Si readout integrated circuit (ROIC) and have excellent operability, low dark current, high quantum efficiency (QE), good uniformity and high yield. Comprehensive characterization of FPA performance was performed from room temperature to LN2, and the test results are presented and discussed in this paper. Typical operability is ~99.9%, and peak QE ~85%. FPA noise is background limited at -70°C with field-of-view (FOV) ~100° and becomes lab camera electronics limited when FOV ~0°. Pixel dark current either matches or is below the values from Rule-07 model over a wide temperature range. Noise equivalent irradiance (NEI) of 2-3E9 Ph/cm²-s is achieved at -70°C and could be further reduced under smaller FOV.

Fast and non-destructive quality control tools are important to assess the reliability of photovoltaic plants. On-site inspection is essential to minimize the risk of module damage and electrical yield losses. This may only be achieved by using highly sensitive imaging techniques such as luminescence or infrared thermography imaging. Nowadays, electroluminescence is used to detect defects such as local cell changes, series resistances and shunts in solar cells and modules which can cause electrical losses. However, the drawback of this method is the relatively low measurement throughput. To increase the throughput InGaAs cameras with a resolution of 640 × 512 pixels are used, for which low integration times are possible to acquire electroluminescence images. For such low integration times even moving image acquisition and movie recording are feasible to detect the mentioned defects. In this paper, an outdoor electroluminescence setup is presented for mobile handheld recording. Experiments showed that 5 ms integration time is a good compromise between low contrasts for lower integration times and motion blurring for higher integration times. The camera prototype has an onboard computer to avoid image transmission losses. It was controlled and visualized over Wi-Fi and remote desktop connection. The energy supply was provided from LiPo-batteries for improved mobility. In comparison to conventional electroluminescence measurements we can decrease the measurement time of a 20 module string from 5 min to 20 s.

The importance of a constant blood glucose concentration monitoring in order to keep a regular control for diabetic patients, had been established from the medical approach. Several studies accept the necessity of exploring alternatives for the traditional digital glucometer, given the pain and discomfort related to this technique, which can lead to a compromised control of the disease. Numerous efforts based on the application of IR spectroscopy for non-invasive glucose quantification had been done with favorable, yet not conclusive results, given in part from the research protocols defined, which had not considered the compounds involved in the glucose regulation mechanism, it’s known that this substances have an important role from both the biochemical and optical perspective. Therefore it’s necessary to apply an interdisciplinary study based on the properties of the glucose in the human body, to understand the interaction between this substance, its surroundings and light from the mid-IR region. From our results, the window of interest for blood glucose is in the spectral range of 1150-950cm^-1. This study proposes a comprehensive approach of glucose quantification by means of mid-IR absorption spectroscopy, considering important biochemical, physiological and optical properties, we also propose the use of chemometric tools for the analysis of the bio-optical signals. The results of this work would help to define the right parameters aiming to obtain an optical glucose quantification system and protocol.

Mercurous halides; mercurous iodide (Hg₂I₂), mercurous bromide (Hg₂Br₂) and mercurous chloride (Hg₂Cl₂) are high figure of merit materials for fabricating Acousto-optic (AO) devices that operate in the visible and infrared regions. Single crystals of mercurous halides were grown by physical vapor transport (PVT) method. Thermal expansion as well as the effect of annealing on the material are discussed. Mercurous halides show positive thermal expansion along "a" axis whereas no significant thermal expansion along "c" axis. The coefficients of thermal expansion of Hg₂Cl₂, Hg₂Br₂ and Hg₂I₂ are 6.72 × 10-5 °C^-1, 6.44× 10-5 °C^-1 and 6.08 × 10-5 °C^-1, respectively. The optical band gap of Hg₂Cl₂ was calculated using the transmission spectra as 2.9 eV.

Tellurium dioxide is the most widely used uniaxial crystal for acousto-optic devices. Acousto-optic tunable filters based on this material can cover spectral range from UV to MWIR in a non-collinear configuration. The diffracted narrow band output beams have orthogonal linear polarizations, propagating in different directions, allowing the filter to act as polarizing beam splitter/analyzer as well. To achieve full electronic tuning, two liquid crystal variable retarders are used to measure all six polarization states used in the calculation of Stokes vector. We will present the design of the instrument, test results, and performance considerations.

In this work a design and analysis of a Fabry-Perot interferometer (FPI) based on a silicon wafer for possible application in a SF6 gas sensor used in electric power systems is presented. The sensor design is based on cross correlation spectroscopy principle with an FPI, which acts an optical modulator. Hence, due to characteristics of the FPI transmission spectrum, it can be used detect molecules with very well defined ro-vibrational lines such as those produced by diatomic and linear molecules. The design of the FPI depends mainly of the SF6 absorption wavelength peaks and of the optimum thickness of the silicon wafer. For this reason, in order to measure this absorption peaks a HITRAN database was used. The optimum thickness of the silicon wafer was calculated and simulated transmission spectrum. Finally, we demonstrated by using analytical simulations that a silicon wafer can be implemented as a FPI and used in a SF6 gas sensor.

An embedded fiber optic sensor based on the photonic crystal fiber is proposed to measure the transverse stress in composited material for structural health monitoring. The sensing principle has been analyzed and validated by experiments. The 0.1%F.S high precision calibration device has been designed to indicated that linear correlation between the wavelength shift of Sagnac loop and pressure, and the good performances of sensor, such as the sensitivity coefficient is 0.1285nm/N, linearity is accessible to 1.02%F.S, maximum error is 3%F.S. Other experiments have been done by a material testing machine on the sensor, which have shown that the sensitivity coefficient is increasing with sensing length but immune with the shape of sensor. The sensor will be suitable for solving the problem of high precision online pressure monitoring in some complex structure health monitoring.

The Cr/Hg₃In₂Te₆/Cr surface-barrier structures, photosensitive in the range of 0.5-1.8 μm, have been studied by optical, electrical and photoelectric measurements. The remarkable feature of the created diodes was using the same metal (Cr) to form both Ohmic and rectifying contacts employing different surface treatments of the corresponding semiconductor faces. This simplified the fabrication technology and increased radiation resistance of the photodetectors. Dark (leakage) currents of the photodiodes at reverse bias of 10 V did not exceed 3-5 μA for the photosensitive contact area of 1 mm². The monochromatic current sensitivity was 1.1-1.2 A/W at the spectrum maximum (1.57 μm) and such photodetectors showed high temperature stability. In the range from -40 °C to +40 °C, the sensitivity at the maximum varied within 10- 15% that corresponded to the temperature coefficient of photosensitivity (TCP) ~ 0.2% per degree. From -10 °C to +20 °C, TCP was < 0.05% per degree. Thermoelectric cooling can significantly improve the photodetector characteristics.

Aiming at the influence of the energy distribution of incident light on the traditional location algorithm of four-quadrant detector (4-QD), the generation rule of measurement error is analyzed. A model to express the energy distribution of the light spot of 4-QD is established by using characteristic parameters, and the measurement error model related to the characteristic parameters is derived. In the actual system, for different spot locations, we can use this model to fit the energy distribution, and get the spot characteristic parameters of the system, and then use it to calculate the measurement error caused by the traditional algorithm in 4-QD system. In the experiment, the energy distribution image of the incident beam is obtained by the beam quality analyzer, and the actual moving distance of the spot is compared with the calculation result of the traditional measurement algorithm. From the experimental results, it can be proved that the measurement error model of the four-quadrant detector, which is described in this paper, is consistent with the experimental results. It can further modify the calculation results of the 4-QD system in practical applications, to improve the measurement accuracy.

The traditional pulse laser ranging system based on the measurement of time of flight often ignores the nonlinear influence of the intensity of the echo light power on the range error of the receiver system. Based on the transistor model (Gummel-Poon model), this paper makes a systematic modeling of the pulsed laser range finding receiver system. By means of computer aided analysis, the relationship between the input current waveform and the leading edge of the response pulse of the receiving system is analyzed. And thus, the relationship model of the echo light power and front of response echo pulse is derived in the paper. Based on the above model and by involving the method of differential threshold time discrimination, the walking error in the laser ranging system is corrected. Finally, the experimental results show that this method can effectively correct the nonlinear error caused by the fluctuation of the echo power and improve the accuracy of the ranging system.

The management of fish stocks in Chile caught by small-scale fishing boats are subject to catch quotas. Due to the massive number of fish landings, solely a very small number of landings can be inspected. In this paper, we present the first step in order to develop a vision system for automatically checking the fish quotas. This first step consists in automatically classifying the different fish species that must be checked, based upon the hypothesis that different small pelagic fish species should have different spectral signatures. Thus, we collected hyperspectral cubes, in the Near Infrared (NIR) band, for the following three species of interest: Chilean Silverside (Odontesthes regia), Southern Rays Bream (Brama australis), and Silver Hake (Merlucciidae). The hypercubes, containing 256 spectral bands in the range of 900-1700 nm, were processed and labeled to obtain the spectral signatures of the species. The spectral signatures were used to develop k-nearest neighbor and support vector machine classifiers. Their performance was compared using n-fold cross-validation and 5000 trials. When only a small subset of spectral bands was used by the classifiers, the average classification rate achieved was approximately 80%. When the entire spatial-spectral information was used, the average classification rate raised to 90%.