Stray Light Analysis Of The Coded Aperture Spectral Imager Based On DMD

Coded aperture imaging spectrometer has become a hotspot in the field of spectral imaging in recent years due to its advantages of high optical flux and flexible coding.Using Digital Micromirror Device(DMD)instead of traditional mechanical template as coding element has higher optical efficiency and can better play the advantages of coding aperture imaging spectrometer,but at the same time,it brings new challenges to the improvement of optical system performance.Since the diffraction effect of DMD will lead to the generation of stray light in the system,and then reduce the imaging quality and signal-to-noise ratio of the system,it is necessary to analyze the diffraction characteristics of DMD.At present,many scholars have established diffraction models according to the structure and working principle of DMD,which has certain reference and guiding significance for the application of DMD.However,there are no in-depth reports on the influence of DMD diffraction effect on stray light of optical system.Therefore,the influence of DMD diffraction stray light on the optical system is analyzed and studied in this paper.The main work contents include the following aspects:(1)Studied the composition and working principle of DMD,and its diffraction effect was analyzed.By comparing the application range,solution method and advantages and disadvantages of various diffraction theory algorithms,the optimal algorithm suitable for analyzing the diffraction characteristics of DMD was found,that is,the mathematical model of DMD was built based on the strict coupled wave theory,and the expression of DMD diffraction efficiency was deduced,which provided a theoretical basis for the simulation analysis of DMD.(2)Discussed the simulation modeling scheme of the dmo will find diffraction mechanism in the simulation analysis method,study the different wavelength and incident Angle on the DMD diffraction efficiency and the effect of optical system was analyzed in DMD antecedent system parameters on the influence of stray light,to include the dmo components of optical system design and stray light analysis provides a certain reference.(3)Analyzed the DMD coded aperture imaging spectral stray light in the system,according to the design requirements,spectrum system to modeling the light machine system,the main source of stray light is given and scattering path determined by ray tracing system,analyzed the dmo and grating diffraction stray light,and draw the system of mixed light inhibition PST curve,finally put forward the corresponding suppression measures to reduce the influence of stray light on the system,in order to further improve the performance of the system to provide the technical support.