Portable and High-throughput UV Raman Spectroscopy for Standoff Explosive Detection

F. Vasefi
SafetySpect Inc., United States

Keywords: UV Raman Spectroscopy, explosives, Spatial Homodyne Spectrometer

We present co-development of the reflective Spatial Heterodyne Spectrometer (rSHS) with JPL-NASA as a miniature, all-reflective two-beam cyclical interferometer that can observe targeted atomic and molecular gas spectral lines at high spectral resolution. It comprises a grating and reflective optics tailored to a target wavelength region (UV to IR) with a 2-D solid-state array detector that produces optical interference fringes, whose Fourier transform produces high-resolution spectra. With its high optical throughput (├ętendue) and wide field of view (FOV), it has high sensitivity to weak or diffuse sources. SHS shares some similarities with the traditional Fourier Transform Spectrometers (FTS) but offers a simpler approach to an optical geometry readily made compact and robust to alignment and high tolerance to environmental optomechanical and temperature variations. In UV wavelengths, a diffraction grating spectrometer is large and have very low throughput. Tunable filter based Raman Spectroscopy have low spectral resolution and require more power to run. Reflective Spatial Heterodyne Spectrometers have many unique advantages over all previously-reported Raman spectrometers.