High-Speed Resonant FTIR Spectrometer for Surface Contaminant Measurements

OPTRA proposes the development of a high speed resonant Fourier transform infrared (FTIR) spectrometer for surface contaminant detection via thermal luminescence. The system will generate 10,000 spectra per second over the 7-14 m spectral range at 8 cm-1 spectral resolution; the NESR is projected at 4×10-9 W/(cm2•ster•cm-1) over a 100 s integration time. The key to the system is a resonant scanner driven by a high speed actuator such as a piezo-electric transducer. The benefit of the resonant scanning is significantly reduced drive power requirements, since the actuator must only replace the losses due to damping within the system. The second key aspect is a multi-pass, reciprocating interferometer configuration which greatly reduces the physical stroke length required for a given spectral resolution. Our configuration results in two reflections off the reciprocating scanning mirror at a 45° angle of incidence; the result is a 5.7× reduction in the required stroke length relative to the standard Michelson interferometer configuration. The overall solution will offer an unprecedented combination of high spectral acquisition rate and sensitivity, making it an ideal tool for the further development of thermal luminescent detection of chemical warfare agents and toxic industrial chemicals on surfaces.