VIS-NIR Lightweight Spectrometer for the Sun and the Moon

EPIR Inc. and Brimrose Technology Corporation propose a miniaturized spectrometer covering the 0.35 to 2.3um wavelength range by integrating a Hg1-xCdxTe (MCT) - based photodetector (PD) with an acousto-optic tunable filter (AOTF). The goal is to achieve 4um spectral resolution with wide dynamic range to measure both the Sun's and the Moon's radiometric characteristics. Currently the best known infrared photon detectors used for spectroscopy are based on MCT. With an adjustable bandgap and little lattice mismatch, MCT photon detectors with high quantum efficiency are sensitive to a very broad spectral range. The proposing company, EPIR, is the leading small business in MCT growth, characterization and focal plane array (FPA) fabrication. The spectroscopic filter is an important component of any spectrometer. Compared with other technologies, e.g. Michelson or Offner interferometers, the proposed AOTF offers high spectral resolution, with the advantages of high speed, programmable waveband selection flexibility, and arbitrary wavelength step size. An AOTF has no moving parts and can be integrated with a MCT photodetector monolithically. The biggest advantage of the proposed spectrometer is its compact system design that reduced size, weight, and power consumption (SWaP), offering significant benefits to the payload as well as in the operation of missions.