基于轴向移动柱面-泽尼克校正元件的动态像差校正技术

Variable aberration correction technology based on axially shifting cylinder-Zernike correcting element

椭球形窗口光学系统最显著的特点在于其依赖扫描视场的动态像差变化特性,像散和彗差成为影响光学系统成像质量的主要因素,其中像散的影响最为突出。为解决这一难题,结合柱面透镜和泽尼克位相板的特点,提出了一种新颖的动态像差校正方法,即柱面-泽尼克元件校正方法,此元件的外表面为一对母线互相垂直的圆柱面,对应的两个内表面为泽尼克边缘矢高表面。该方法随扫描视场的变化实时地调整一对柱面-泽尼克校正元件间距以实现椭球形窗口引入像差的动态校正。突破了固定校正元件无法实现超大扫描视场的瓶颈。设计实例中成像光学系统实现了±55°扫描视场,各扫描视场像散和彗差的泽尼克像差系数P-V值校正到了±0.8个波长以内,椭球形窗口光学系统的成像质量得到了明显的提高。

The most significant feature of elliptical window optical system is dynamic aberration change which is dependent on the scanning field. Thus, astigmatism and coma become the main factors which influence imaging quality of the optical system and the effect of astigmatism is most prominent. In this paper, a new method for dynamic aberration correction was presented in order to solve this problem. And this so-called cylinder-Zernike element correcting method combines the characteristics of cylindrical lens and Zernike plate. The outer surfaces of cylinder-Zernike correcting element were a pair of cylindrical surfaces whose generating lines were mutual perpendicular and the corresponding internal surfaces were Zernike fringe sag surfaces. This method could adjust the distance between the two cylinder-Zernike correcting elements in real time according to the change of scanning field to realize the correcting of dynamic aberration induced by elliptical window. It breaks through the bottleneck that the fixed correcting elements achieves scanning system is cannot achieve super wide scanning field. The imaging optical system in the giving example -＋55~ scanning field. The Zernike aberration coefficients of astigmatism and coma in each field are corrected into _＋0.8 wavelength and the imaging quality of the elliptical window optical greatly improved.