Novel standoff detection system for the classification of chemical and biological hazardous substances combining temporal and spectral laser-induced fluorescence techniques⋆

Abstract

In an effort to reduce the potential risk of human exposure to chemical and biological hazardous materials, the demand increases for a detection system which rapidly identifies possible threats from a distance to avoid direct human contact to these materials. In this scope, we present a novel detection system which is able to measure simultaneously spectrally and temporally resolved laser-induced fluorescence (LIF) signals excited by two consecutive laser pulses with different central wavelengths at 266nm and 355nm. As is shown in this paper, the setup enables fast data acquisition that provides a complete dataset in less than a few milliseconds at repetition rates of 100Hz. Furthermore, with its modular design, it can be transported easily for operation at different locations. First measurements indicate a high performance with an accuracy of more than 97% in the distinguishability of bacterial specimen within a limited set of three representative bacterial species, namely Bacillus thuringiensis, Micrococcus luteus and Oligella urethralis. Together with the consecutive classification procedure, the setup promises to become a valuable tool for standoff detection of bio-hazards.