Design and theoretical analysis of a field-widened cross-dispersed spatial heterodyne spectrometer based on multi-gratings and a postposed transmission grating

This paper presents a modified field-widened cross-dispersed spatial heterodyne spectrometer that incorporates multi-gratings and a postposed transmission grating (MGPG-FWCDSHS). The use of multi-gratings enables broadband, high-resolution measurements. By placing the longitudinal-dispersion grating after the lateral-dispersion gratings, the system avoids mutual interference caused by overlapping interferograms, thus enabling effective field widening. An accurate solution for the field-widening prisms is derived, addressing the inaccuracies of traditional field-widening models. The MGPG-FWCDSHS offers high resolution, high throughput, stability, and broadband coverage, making it suitable for high-sensitivity, high-resolution, and spectral measurements.