Imaging stand-off detection of explosives by quantum cascade laser based backscattering spectroscopy

In this contribution we present the results of an imaging stand-off detection system based on a mid-IR external-cavity quantum cascade laser (EC-QCL) with a broad tunable range of 200 cm^-1. Traces of TNT (trinitrotoluene) and PETN (pentaerythritol tetranitrate) as well as various non-hazardous substances such as flour or skin cream on different substrate-materials were investigated by illuminating them with the EC-QC laser and collecting the diffusely backscattered light. By tuning the EC-QCL across the significant absorption spectra we were able to detect the explosives