一种基于数字微镜星模拟器的衍射校正方法

A Diffraction Correction Method Based on Digital Mirror Device Star Simulator

为解决星模拟器在光谱模拟时存在的衍射问题,提出一种消除数字微镜设备衍射效应的方法。建立标量衍射模型,将数字微镜设备等效为二维闪耀光栅,以光栅衍射理论为基础寻找影响衍射能级的因素,并推导出入射角与衍射效应的耦合关系。当光束沿数字微镜设备对角线入射,高度角为24°时,衍射效率达到最大化提高,衍射效率提高近12%,此时衍射损耗能量最少,数字微镜设备反射时存在衍射效应达到最小,通过ZEMAX优化设计出Czerny-Turner光学结构,校正系统像差。优化结果表明,在500~900 nm谱段内,光谱模拟精度优于5%,全谱段的光谱分辨率优于5 nm,可有效提升星敏感器地面标定精度。

In order to solve the diffraction problem in the spectrum simulation of the star simulator,a method to eliminate the diffraction effect of the Digital Mirror Device(DMD)is proposed.A scalar diffraction model is established,and the DMD is equivalent to a two-dimensional blazed grating.Based on the grating diffraction theory,the factors affecting the diffraction energy level are searched for,and the coupling relationship between the incident angle and the diffraction effect is deduced.When the light beam is incident along the diagonal of the DMD and the height angle is equal to the angle of height,the diffraction efficiency is maximized,and the diffraction efficiency is increased by nearly 12%.At this time,the diffraction loss energy is the least,and the diffraction effect when the DMD reflects is minimized.Through ZEMAX Optimal design of Czerny-Turner optical structure to correct system aberrations.The optimization results show that the spectral simulation accuracy is better than 5%in the 500~900 nm spectral range,and the spectral resolution of the full spectral range is better than 5 nm,which can effectively improve the ground calibration accuracy of the star sensor.