Theoretical analysis of compact ultrahigh-spectral-resolution infrared imaging spectrometer

A compact ultrahigh-spectral-resolution imaging spectrometer (CUSRIS) is presented, which combines an entrance slit, a scanning Fabry-Perot interferometer (FPI), a static grating interferometer (SGI) and a cylindrical lens. The SGI consists of a beam splitter, a fixed reflection grating in Littrow configuration, and a fixed plane mirror. For each point of the entrance slit, one spectral image is obtained at each FPI spacing position, and multiple spectral images are obtained to synthesize an ultrahigh-spectral-resolution spectral image. First-order approximations of system performance are given. The CUSRIS is a unique concept that not only obtains spatial information and ultrahigh-resolution spectral information (e.g., resolving power higher than 1,000,000) in the near-infrared, short-wave infrared or mid-wave infrared region, but also has the advantages of compact size and short measurement time compared with the existing ultrahigh-spectral-resolution infrared imaging spectrometers.