Explosives standoff detection using Raman spectroscopy: from bulk towards trace detection

This paper gives a brief overview on our latest progress in the area of standoff detection. Standoff Raman measurements from 200 m and 470 m distance have been performed on bulk amounts of TATP and AN respectively, the former through a double sided window, the latter under heavy rain. Resonance Raman measurements on TNT, DNT and NM vapors in the ppm concentration regime are presented, showing resonance enhancement in the range of 2 200 (NM) to 57 000 (TNT) as compared to 532 nm Raman cross sections. Finally, the application of hyper spectral Raman imaging is described, exemplified by the resolution of four different samples (sulphur, AN, DNT, and TNT) in the form of 5 mm wide discs in one single image.