Spatial heterodyne spectrometer based on the Mach–Zehnder interferometer

• We propose a spatial heterodyne spectrometer based on Mach–Zehnder interferometer.
• Non-linear problem is avoided in the broad spectral band conditions.
• As a dual output system, all the energy entering into the system can be recorded.
• We set up an optical model of this spectrometer in ZEMAX.
• Two kinds of interferograms are generated in MATLAB and ZEMAX.

Spatial heterodyne spectroscopy (SHS) is a new kind of Fourier-transform spectroscopic technique capable of very high spectral resolution. In this paper, a spatial heterodyne spectrometer based on the Mach–Zehnder interferometer (MZ–SHS) is proposed. It is modified by replacing one mirror in the Mach–Zehnder interferometer with a diffraction grating. This technique retains many of the advantages of traditional SHS. Moreover, the spatial frequency of the interferogram is strictly linear with wavenumber. We describe the concept of the new MZ–SHS and elaborate the exact expression of the interferogram. Also, a design example and two kinds of imitated interferograms are presented in this paper. One is simulated in MATLAB and the other is generated in ZEMAX using ray tracing method. The retrieved spectra from these two interferograms show a good agreement with the theoretical results.