Experimental Set-Up for the Design of Deep Ultraviolet Raman Spectroscopic Applications for Standoff Detection of Hazardous Substances

Abstract

Despite its immediate applications, selective detection of trace quantities of surface adsorbed chemicals, such as explosives, without physically collecting the sample molecules is a challenging task. Standoff spectroscopic techniques offer an ideal method of detecting chemicals without using a sample collection step. Though standoff spectroscopic techniques are capable of providing high selectivity, their demonstrated sensitivities often are poor. Especially, Raman spectroscopy promises highest selectivity, but a number of challenges have to be managed in order to succeed in the detection of tiny amounts of substances [1-3]. In order to manage standoff Raman spectroscopic challenges, i.e. retrieving spectral signatures of traces on an unknown, possibly fluorescent background, measuring in an open, public environment and under deep UV conditions, a basic setup for the standoff detection of trace quantities of surface adsorbed chemicals using deep UV Raman is described and characterized at an excitation wavelength of 264 nm. This set-up promises to be an aid for future, compact UV Raman equipment for standoff applications from ~2 m and above.