US EPA

5933738 

Journal Article 

Active infrared multispectral imaging of chemicals on surfaces 

Goyal, AK; Spencer, M; Kelly, M; Costa, J; Diliberto, M; Meyer, E; Jeys, T 

2011 

Unk 

Proceedings of SPIE
ISSN: 0277-786X
EISSN: 1996-756X 

SPIE-INT SOC OPTICAL ENGINEERING 

Orlando, FL 

Proceedings of SPIE 

8018 

80180N 

English 

10.1117/12.882698 

WOS:000297515800019 

We investigated the signature phenomenology of long-wave infrared (LWIR) reflectance of contaminated surfaces using a quantum-cascade laser (QCL) that tunes from lambda = 9.1 to 9.8 mu m and a HgCdTe focal-plane-array (FPA) with custom read-out integrated circuit (ROIC). A liquid chemical, diethyl phthalate (DEP), was applied to a variety of substrates such as diffusely reflecting gold, concrete, asphalt, and sand. Multispectral image-cubes of the scattered radiation were generated over 81 wavelengths in steps of 1 cm(-1) at standoff distances ranging from 0.1 to 5 meters. For idealized substrates such as diffusely reflecting gold, the experimentally measured signatures are in good agreement with theoretical calculations. Clear signatures were also obtained for contaminated concrete, asphalt, and sand. These measurements demonstrate the potential of this technique for detecting and classifying chemicals on native outdoor surfaces. 

chemical imaging; multispectral imaging; hyperspectral imaging; vibrational spectroscopy; infrared spectroscopy; quantum cascade lasers; HgCdTe; focal plane arrays 

Fountain, AW; Gardner, PJ; 

Conference on Chemical, Biological, Radiological, Nuclear, and Explosives (CBRNE) Sensing XII 

Orlando, FL