We perform active hyperspectral imaging using tunable mid-infrared (MIR) quantum cascade lasers for contactless identification of solid and liquid contaminations on surfaces. By collecting the backscattered laser radiation with a camera, a hyperspectral data cube, containing the spatially resolved spectral information of the scene is obtained. Data is analyzed using appropriate algorithms to find the target substances even on substrates with a priori unknown spectra. Eye-save standoff detection of residues of explosives and precursors over extended distances is demonstrated and the main purpose of our system. Using a MIR EC-QCL with a tuning range from 7.5 μm to 10 μm, detection of a large variety of explosives, e.g. TNT, PETN and RDX and precursor materials such as Ammonium Nitrate could be demonstrated. In a real world scenario stand-off detection over distances of up to 20 m could be successfully performed. This includes measurements in a post blast scenario demonstrating the potential of the technique for forensic investigations.

Date Published: 25 May 2016
PDF: 9 pages
Proc. SPIE 9836, Micro- and Nanotechnology Sensors, Systems, and Applications VIII, 98362I (25 May 2016); doi: 10.1117/12.2223581

Published in SPIE Proceedings Vol. 9836:
Micro- and Nanotechnology Sensors, Systems, and Applications VIII
Thomas George; Achyut K. Dutta; M. Saif Islam, Editor(s)