Optimization of a Michelson interferometer with a rotating retroreflector in optical design, spectral resolution, and optical throughput

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Abstract
A newly designed Michelson interferometer for Fourier spectroscopy [ J. Opt. Soc. Am. A 8, 1991 ( 1991)] utilizes a nutating retroreflector (cube corner mirror) to generate alterations in geometrical and optical paths. The practical optomechanical design of a Fourier-transform spectrometer incorporating a rotating retroreflector for path-length alteration is considered. [The instrument has been given the name MIROR, for Michelson Interferometer with a Rotating Retroreflector.] Two parameters of the instrument are essential: the maximum optical path difference, which yields the spectral resolution of the instrument, and the diameter of the transmitted beam, which determines the throughput and hence the achievable signal-to-noise ratio. The maximum allowable beam diameter is calculated as a function of the geometry and the orientation of the rotating retroreflector and the other optical components. The geometrical configuration and the orientation of all the optical components with respect to one another are also optimized for the maximum transmitted beam diameter when the required path difference is given. A principal investigation of different possible configurations of the optical components is presented. Then a quantitative optimization for an interferometer employing a retroreflector having a 5-in. (12.7-cm) aperture diameter requiring an optical path difference of more than 10 cm (spectral resolution better than 0.1 cm−1) is performed. Finally a simplified but enhanced design is described.