Massachusetts Institute of Technology

Salvatore Di Cecca

Shawn Michael Redmond

Patrick Hassett

A two-layer hybrid solid wedged etalon was fabricated and combined with a traditional imager to make a compact computational spectrometer. The hybrid wedge was made of NbOand Infrasil 302 and was designed to operate from 0.4-2.4 &#x3bc;m. Initial demonstrations used a CMOS imager and operated from 0.4-0.9 &#x3bc;m with spectral resolutions &#x3c;30 cmfrom single snapshots. The computational spectrometer operates similarly to a spatial Fourier Transform infrared (FTIR) spectrometer with spectral reconstruction using a non-negative least squares fitting algorithm based on analytically computed wavelength response vectors determined from extracted physical thicknesses across the entire two-dimensional wedge. This computational technique resulted in performance and spectral resolutions exceeding those that could be achieved from Fourier techniques. With an additional imaging lenses and translational scanning, the system can be converted into a hyperspectral imager.

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Salvatore Di Cecca