Optical simulation of large aperture spatial heterodyne imaging spectrometer

Large aperture spatial heterodyne imaging spectrometer (LASHIS) is a new pushbroom Fourier transform ultraspectral imager with no moving parts. It is based on a Sagnac interferometer combined with a pair of gratings. In this paper, the basic principle of LASHIS is reviewed and an optical LASHIS model is set up in ZEMAX. Three interference images are presented, one is calculated according to the basic theory, one is simulated using the optical model in ZEMAX, and the other is generated by the experimental device set up in our laboratory. These three interference images show a good agreement with each other that demonstrate the correctness of the optical model. Using this model, we can simulate the interference image quickly. This image gives a visualized evaluation of the system performance, and it will be more convenient for system design or tolerance analysis of LASHIS.