Stand-off hyperspectral imaging – towards mobile, high throughput remote chemical identification and quantification using chemometrics

Stand-off Raman spectroscopy is a versatile tool for a variety of applications, such as safety investigations, forensics or geosciences. During the project “OPTIX” (FP7) we showed that the detection of small amounts of explosives and hazardous chemicals at distance of 100 m is possible even through opaque containers. Here, we present a different approach to remote Raman sensing employing hyperspectral Raman spectroscopy. The classical grating as a dispersion element is exchanged in favor of a liquid crystal tunable filter (LCTF), which allows for direct imaging of a selected Raman shift onto the intensified CCD (iCCD). This maintains a high degree of local information and allows for higher throughput, as whole areas can be imaged at once. Measurements with our first prototype, still equipped with a water-cooled, flashlamp-pumped excitation laser, as well as first measurements with a diode pumped, air cooled, small laser are shown. The capability of remote chemical analysis incorporating chemometrics on a reference sample consisting of different polymers will be presented.