Solid State Ultraviolet Spatial Heterodyne Raman System for Standoff Explosives Detection

Physical Sciences Inc., in collaboration with Science and Engineering Services, LLC and Czitek LLC, will develop a compact deep ultraviolet (DUV) Raman sensor for identification of explosive residues from unmanned ground vehicles. The Raman sensor utilizes a state-of-the-art solid-state DUV laser developed by SES during DARPA’s Laser UV Sources for Tactical, Efficient Raman (LUSTER) program and a rugged, high throughput spatial heterodyne interferometric spectrometer developed by PSI. The combination of these two technologies will create an advanced Raman sensor that outperforms currently fielded tactical Raman systems with respect to sensitivity, interrogation area, and standoff range. Feasibility of the sensor architecture was successfully demonstrated in the Phase I program through system modeling and Raman measurements collected with a breadboard DUV spatial heterodyne spectrometer and 235 nm excitation from a LUSTER prototype. Based on the validated system model, the Phase II prototype is projected to achieve 20 cm-1 resolution, an 800 – 2200 cm-1 spectral range, and a 100 mm2 per second interrogation rate while detecting discriminant spectral features of explosives with a signal-to-noise ratio of 5 against a 40 ug/cm2 areal density. Initial estimates indicate the Phase II prototype will weigh ~20 lbs., occupy ~2 ft3, and consume ~400 watts.