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18 May 2020 Laser-based long-wave-infrared hyperspectral imaging system for the standoff detection of trace surface chemicals
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Abstract

A trace chemical detector is described that combines external-cavity quantum cascade lasers and a mercury cadmium telluride camera to capture hyperspectral images of the diffuse reflectance from a target surface in the long-wave infrared. The system is able to generate individual hypercubes in <0.1  s. When raster scanning the laser beam over the target surface, areal coverage rates of >60  cm2  /  s have been achieved. Results are presented for standoff distances ranging from 0.1 to 25 m. Hyperspectral images generated by the system are analyzed for spectral features that indicate the presence of trace surface contaminants. This approach has been found to be highly capable of detecting trace chemical residues on a wide variety of surfaces, and we present a collection of detection results to demonstrate the capabilities of this technology. Examples include the detection of 10  μg of saccharin powder on a wide range of substrates, 0.2  μg of an explosive residue on a computer keyboard, residual pharmaceuticals within a plastic baggie, and a contaminated fingerprint on cell phone case.

CC BY: © The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.
Anish K. Goyal, Derek Wood, Vincent Lee, Joshua Rollag, Peter Schwarz, Leyun Zhu, and Gary Santora "Laser-based long-wave-infrared hyperspectral imaging system for the standoff detection of trace surface chemicals," Optical Engineering 59(9), 092003 (18 May 2020). https://doi.org/10.1117/1.OE.59.9.092003
Received: 3 March 2020; Accepted: 29 April 2020; Published: 18 May 2020
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CITATIONS
Cited by 8 scholarly publications.
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KEYWORDS
Reflectivity

Hyperspectral imaging

Long wavelength infrared

Standoff detection

Imaging systems

Reflection

Contamination

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