Optimal Design And Analysis Of The Optical System For Interference Spectral Imaging System In SWIR

Imaging spectrometry is an organic combination of imaging technique andspectroscopic technique that can obtain two-dimensional spatial information andone-dimensional spectral information of the goal. So it becomes the cutting-edgescience in today’s visible and infrared remote sensing field. With the development ofspace remote sensing technology, the imaging spectrometer is required to be with widespectrum, large-aperture, and high-flux, high stability, thus raise a higher demand on thedesign of the optical system.This paper studies the optical system’s optimal design problem of a wide-bandshort-wave infrared interference imaging spectrometer. This paper first introduces thedevelopments of interference imaging spectrometer technology, and status developmentof SWIR interferometer imaging spectral technology in the world; then the parametersof the optical system are calculated according to the SWIR interferometer spectralimaging system’s performance requirements. After that the pre-objective, interferometer,the collimating lens and the imaging lens are designed.The design scheme was discussed according to the front object’s characteristics oflong-focal-length, wide spectrum and small field-of-view. Ritchey–Chrétien catadioptricsystem was chose as optimization scheme. Different focal ratio of the primary mirror ofF/2, F/1.5, F/1.2was selected in the optimal design. The design results show that lowfocal ratio of the primary mirror can effectively reduce the system’ size and provide adesign basis for improving system’s resolution.To reduce the system’s volume, raise system’s stability and use the solid blockSagnac interferometer, optimal design of and analysis of the Sagnac interferometer isdiscussed, which shows the interferometer’s dimension varying with the telescope’smagnification. According to the analysis result, at the same time taking care of thecollimation system’s feasibility, value of the telescope magnification and structure sizeof Sagnac interferometer were got.Based on this, the optimization design of the collimating lens and the imaging lens are discussed. The design focused on the material properties analysis of the short-waveinfrared and matching of achromatic materials. The final whole system has theadvantages of small size, high stability and high image quality, high flux.Introduced on the basis of the optical design, stray light analysis of thefore-objective was studied after the significance of the stray light analysis and it’scommonly used methods are introduced. The hood and vane were designed to deducethe stray light radiation. The software’s simulation and test results show that thesuppression measures control the stray light radiation within the allowable range.