A design of temporally and spatially modulated infrared Fourier transform imaging spectrometer using subpixel supersampling

The spectral resolution of The Temporally and Spatially Modulated Fourier Transform Imaging Spectrometer (TSMFTIS) is mainly determined by the optical focal length, lateral shear, and the performance of the infrared focal plane array (FPA) in combination. However, due to the limited number and density of pixels in the FPA, the lateral shear of the optical system is constrained, resulting in the overall spectral resolution of the instrument unable to be higher. Therefore, this paper proposes achieving super-sampling of the detector for interference images by performing multiple subpixel shifts on the FPA detector. This method supports the continuous increase of lateral shear amount, ultimately improving the overall spectral resolution of the instrument. Experimental results show that using a 384x288 uncooled infrared FPA and under conditions of eightfold super-sampling and 8000μm lateral shear, the instrument's spectral resolution increased from 15.75 cm-1 to 2.31 cm-1.