Design And Theoretical Analysis Of A Medium Wave Infrared Fourier Transform Imaging Spectrometer

Imaging spectrometer is a new generation of optical remote sensing instruments that developed on the basis of imaging spectroscopy technology. It is the combination of the imager and spectrometer. It can acquire three-dimensional information cube for the object target and has been widely used in space remote sensing, target detection, geological resources exploration, environmental monitoring and meteorological analysis. As a typical representative of the imaging spectrometer, the Fourier transform imaging spectrometer (FTIS) obtains the interference information of the object target firstly and then obtains the spectral information via the Fourier transform on the interferogram. According to different modulation of the interferogram, the FTIS can be classified as temporally modulated, spatially modulated, and spatial-temporally modulated.According to the current development status and application requirements for the FTIS, we propose a spatial-temporal modulation FTIS of Medium Wave Infrared. In this system, the moving mirror in traditional temporally modulated FTIS is replaced by multi-step micro-mirrors to realize the static design and the spatial sampling for the optical path difference. Compared with the traditional spatially modulated FTIS, it has no slit and is superior with larger luminous flux and higher energy efficiency.The works of this paper includes four parts:1. Proposed a spatial-temporally modulated FTIS structure which based on the multi-step micro-mirror, the process of interference and the distribution of the optical path difference were analyzed. The modeling and simulation work of the system were completed. The parameter of the optical system was calculated according to technical specifications of this FTIS system.2. The analysis of the overall optical system of this imaging spectrometer was completed. According to the analysis, we established the principal ray model for this system. By using this model, parameters for the front and the rear imaging system were calculated and analyzed.3. The off-axis aberrations introduced by the tilted beam splitter and compensator to the system were analyzed. On the basis of this analysis, three different aperture optics systems of this FTIS were analyzed and designed. The spatial resolution of three optical systems was:2.5m@2000m,0.83m@2000m, 0.3125m@2000m. When the aperture of the imaging beam is relatively large, a method that uses Zernike surface and cylindrical lens to eliminate the off-axis aberrations introduced by the tilted beam splitter and the compensator plate was proposed and this method has good result. Tolerance analysis and athermalization design of the three systems were completed..4. The integration and alimenting work of the imaging spectrometer system were completed. A series experiments were carried out in the laboratory results are fine.