主镜台阶数目对衍射成像系统传递函数的影响分析  

Effect of the number of primary lens level on the MTF of diffractive imaging system

作　　者：刘盾 杨伟[1] 吴时彬[1] 伍凡[1] Dun Liu Wei Yang Shibin Wu Fan Wu(Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, China University of Chinese Academy of Sciences, Beijing 100049, China)

机构地区：[1]中国科学院光电技术研究所,成都610209 [2]中国科学院大学,北京100049

出　　处：《光电工程》2017年第8期786-790,共5页Opto-Electronic Engineering

基　　金：国家重点研发计划地球观测与导航重点专项(2016YFB0500200)

摘　　要：为研究位相型菲涅尔透镜台阶近似引起的衍射杂散光对衍射成像系统调制传递函数(MTF)的影响,本文运用波动光学仿真分析方法模拟光波的传播。通过有限个级次的衍射波面在系统像面上相干叠加,得到系统的点扩散函数(PSF);对其进行傅里叶变换,得到系统的MTF。以菲涅尔主镜口径为80 mm的衍射成像系统为样机,分析了衍射主镜台阶数目为二、四、八时,系统MTF与理论设计值的差异。结果表明,随着衍射主镜台阶数目的增加,衍射杂散光对系统MTF的影响减小;并且四台阶时,与设计值的偏差已经小于0.5%。最后结合几何光线追迹仿真分析,提出将衍射主镜加工成中心区域多台阶、边缘部分为二台阶的思路,降低了衍射杂散光的影响。In order to study the effect of diffractive stray light on the modulation transfer function（MTF） caused by the binary phase-type Fresnel lens, the wave propagation method was used to simulate the propagation of light waves. The point spread function（PSF） of the system was obtained by coherent superposition of infinite diffractive orders, and the MTF was obtained by the Fourier transform of the PSF. The differences between the modified values and the theoretical design values were analyzed when the number of level was 2, 4 and 8 at the diffraction imaging system with an 80 mm Fresnel lens as primary lens. The results show that the effect of diffractive stray light on the MTF of the system decreases with the increase of the number of level. However, the deviation from the design value is less than 0.5% when the level is 4. Finally, we put forward the idea that the central region of the lens is processed into several levels and the edge part is 2-level to reduce the effect of diffractive stray light. The results show that the idea can achieve the purpose of suppressing effect of diffractive stray light.

关 键 词：衍射成像系统 二元位相型菲涅尔透镜 衍射杂散光 调制传递函数 

分 类 号：O436.1[机械工程—光学工程]