SHIELDS -- A Spatial Heterodyne Interferometer for Emergent Line Discrimination Spectroscopy

This proposal advocates the development of the Spatial Heterodyne Interferometer for Emergent Line Discrimination Spectroscopy (SHIELDS), a handheld, man-portable battlespace spectrometer unit which detects chemical, biological, and radiological contaminants using Fraunhofer Line Discrimination. Phase I of this project consisted of modeling and calculations to answer technical questions going into Phase II. The front optics for the SHIELDS assembly was modeled; issues of CCD saturation and minimum signal detection were dealt with; and the Ring effect, a competing Fraunhofer filling-in effect, was modeled for its effect on detection of ground targets. Phase II will produce a full SHIELDS unit for use at 589 nm (the Na Fraunhofer doublet), and a wavelength-agile monolithic Spatial Heterodyne Spectrometer (the first ever constructed) for use with at least two other Fraunhofer wavelengths of interest (such as H-beta, 486 nm; Mg, 518 nm; and H-alpha, 656 nm). The single-wavelength SHIELDS will be tested with a 589-nm fluorophore; and the wavelength-agile system will be field tested with several fluorophores, to show their efficacy in executing Fraunhofer Line Discrimination. This will provide a firm foundation for Phase III.