Tunable spectrometer with acousto-optical tunable filter

Abstract

A tunable spectrometer includes an acousto-optical tunable filter disposed for filtering light from a discrete light source, wherein the light emerges from the filter in a simultaneous plurality of distinct beams having different orders of diffraction, with different diffraction orders having different wavelength ranges and with complementary pairs of said distinct beams having the same diffraction order respectively having substantially the same wavelength ranges. The filter is tuned to diffract light in a simultaneous plurality of distinct beams having different predetermined diffraction orders that have different wavelength ranges that include wavelengths that are characteristic of a spectrum for a given substance; and a set of a given plural number of detectors respectively detect the filtered light diffracted by the filter to thereby simultaneously provide test signals indicative of a spectrum within a spatial region of interest at wavelengths that are characteristic of the spectrum for the given substance. Another spectrometer that detects light at a wavelength that is characteristic of a Raman scattering spectrum for a given substance includes a test cell disposed within the spatial region of interest and including a plurality of mirrors disposed within the cell for reflecting the light to pass a plurality of round trips between the mirrors before emerging from the spatial region of interest to thereby enhance Raman scattering of the light by any molecules of the given substance within the cell while the light passes through the spatial region of interest.