Active infrared multispectral imaging of chemicals on surfaces

Goyal, Anish K.; Spencer, Matthew; Kelly, Michael; Costa, Joseph S.; DiLiberto, Michael; Meyer, Emily; Jeys, T. H.

doi:10.1117/12.882698

Cited by 20 publications

(16 citation statements)

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“…The backscattered signal also contains spectral information that is quasi-orthogonal to PT-IRIS and therefore may offer advantages in a "layered" approach to threat detection [12][13][14][15][16][17][18] . In fact, by removing the IR filter entirely, the MCT focal plane array is sensitive across the full broadband spectral region of the laser system.…”

Section: Preliminary Testingmentioning

confidence: 99%

Broadband infrared imaging spectroscopy for standoff detection of trace explosives

et al. 2016

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This manuscript describes advancements toward a mobile platform for standoff detection of trace explosives on relevant substrates using broadband infrared spectroscopic imaging. In conjunction with this, we are developing a technology for detection based on photo-thermal infrared (IR) imaging spectroscopy (PT-IRIS). PT-IRIS leverages one or more IR quantum cascade lasers (QCL), tuned to strong absorption bands in the analytes and directed to illuminate an area on a surface of interest. An IR focal plane array is used to image the surface thermal emission upon laser illumination. The PT-IRIS signal is processed as a hyperspectral image cube comprised of spatial, spectral and temporal dimensions as vectors within a detection algorithm. Here we describe methods to increase both sensitivity to trace explosives and selectivity between different analyte types by exploiting a broader spectral range than in previous configurations. Previously we demonstrated PT-IRIS at several meters of standoff distance indoors and in field tests, while operating the lasers below the infrared eye-safe intensity limit (100 mW/cm 2 ). Sensitivity to explosive traces as small as a single 10 μm diameter particle (~1 ng) has been demonstrated.

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Section: Preliminary Testingmentioning

confidence: 99%

Broadband infrared imaging spectroscopy for standoff detection of trace explosives

et al. 2016

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“…where α is the absorption coefficient of DEP [2] and t is the film thickness. The best least-squares fit to the data is obtained with A = 0.48 and t = 7.04 μm.…”

Section: Hyperspectral Imaging Demonstrationmentioning

confidence: 99%

“…This expression for A captures to firstorder the factors that reduce the reflectance from a liquid on a diffusely reflecting metallic substrate. Second-order effects, such as the wavelength dependence of the refractive index of DEP [2] and the fact that the film thickness cannot be described by a single value since the substrate is rough, are not captured in this simple calculation. Fig.…”

Section: Hyperspectral Imaging Demonstrationmentioning

confidence: 99%

“…A-HSI in the mid-infrared (MIR) portion of the optical spectrum is of particular interest because the strong and unique absorption features associated with the roto-vibrational modes of molecules allows for chemical identification. MIR A-HSI has a wide range of applications including chemical agent detection [2], explosives detection [3][4][5], biomedical imaging [6][7][8], and forensics [9][10][11]. As compared to alternative detection methods, MIR A-HSI enables scanning with high-areal coverage rates and high sensitivity while the laser intensity at the target remains eye safe.…”

Section: Introductionmentioning

confidence: 99%

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Active hyperspectral imaging using a quantum cascade laser (QCL) array and digital-pixel focal plane array (DFPA) camera

Goyal¹,

Myers²,

Wang³

et al. 2014

Opt. Express

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We demonstrate active hyperspectral imaging using a quantum-cascade laser (QCL) array as the illumination source and a digital-pixel focal-plane-array (DFPA) camera as the receiver. The multi-wavelength QCL array used in this work comprises 15 individually addressable QCLs in which the beams from all lasers are spatially overlapped using wavelength beam combining (WBC). The DFPA camera was configured to integrate the laser light reflected from the sample and to perform on-chip subtraction of the passive thermal background. A 27-frame hyperspectral image was acquired of a liquid contaminant on a diffuse gold surface at a range of 5 meters. The measured spectral reflectance closely matches the calculated reflectance. Furthermore, the high-speed capabilities of the system were demonstrated by capturing differential reflectance images of sand and KClO₃ particles that were moving at speeds of up to 10 m/s.

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“…Recently, the use of quantum cascade lasers (QCLs, Refs. 1 and 2) for stand-off detection 3,4 and spectroscopy 5 in the mid-infrared has increased the demand for wavelengthtunable sources of high output power and good beam quality. Up to now, such systems have employed external cavity QCLs, 6 where wavelength selection and continuous tuning require the rotation and translation of a grating.…”

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confidence: 99%

Master-oscillator power-amplifier quantum cascade laser array

Rauter

Menzel

Goyal

et al. 2012

Applied Physics Letters

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We report on the demonstration of an array of master-oscillator power-amplifier quantum cascade lasers (QCLs) operating in single-mode at different wavelengths between 9.2 and 9.8 μm. In each device, the output of a distributed feedback QCL is injected into a tapered QCL section which acts as an amplifier while maintaining a high beam quality due to adiabatic mode spreading. All array elements feature longitudinal as well as transverse single-mode emission at peak powers between 0.8 and 3.9 W at room temperature. The high output power and excellent beam quality render the array highly suitable for stand-off spectroscopy applications.

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Active infrared multispectral imaging of chemicals on surfaces

Cited by 20 publications

References 0 publications

Broadband infrared imaging spectroscopy for standoff detection of trace explosives

Broadband infrared imaging spectroscopy for standoff detection of trace explosives

Active hyperspectral imaging using a quantum cascade laser (QCL) array and digital-pixel focal plane array (DFPA) camera

Master-oscillator power-amplifier quantum cascade laser array

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