基于自由曲面的紧凑型大视场离轴三反空间光学系统设计  

Design of Compact Large Field Off-axis Three-mirror Space Optical System Based on Freeform Surface

作　　者：陆志贤 李旭阳[1] 任志广 许彤裕 边立国 魏锦洋 姚凯中 LU Zhixian;LI Xuyang;REN Zhiguang;XU Tongyu;BIAN Liguo;WEI Jinyang;YAO Kaizhong(Space Optics Technology Lab,Xi′an Institute of Optics and Precision Mechanics,Chinese Academy of Science,Xi′an 710119,China;University of Chinese Academy of Science,Beijing 100049,China)

机构地区：[1]中国科学院西安光学精密机械研究所空间光学技术研究室,西安710119 [2]中国科学院大学,北京100049

出　　处：《光子学报》2024年第9期166-180,共15页Acta Photonica Sinica

基　　金：国家重点研发计划(No.2021YFC2202100)。

摘　　要：为缩小空间光学系统的体积,降低遥感卫星的发射成本,根据初级像差理论求解光学系统的初始结构,采用视场和面型的渐进式优化策略设计了一款焦距为2000 mm,视场为5°×5°,F数为12.5,外包络圆直径为750 mm,具有“环形轮廓”的离轴三反光学系统。系统的主镜和三镜采用XY多项式自由曲面,次镜采用Zernike多项式自由曲面。根据自由曲面的面型参数,仿真出三个镜面的二维矢高图。设计结果表明系统的成像质量接近衍射极限,各视场RMS光斑直径最大为8.38μm,小于探测器的2个像元尺寸大小。系统能量集中度高,最大相对畸变量为1.88%,最大波前像差为0.053λ,各视场波像差优于λ/18。公差分析结果表明系统成像质量良好,可以满足各项指标要求。In the realm of modern space exploration and remote sensing technology,reflective optical systems play an indispensable role.These systems are distinguished by their absence of chromatic aberration,broad operational bandwidth,effective stray light suppression,and their capacity for lightweight and compact design compared to transmissive systems.These attributes confer significant advantages in the application of space cameras.Particularly under the demands for high resolution and wide field of view,reflective optical systems emerge as the preferred choice due to their unique benefits.In an effort to diminish the physical footprint of space optical systems and reduce the associated costs of launching remote sensing satellites,this paper delineates the formulation of the initial structure for such a system,grounded in the principles of primary aberration theory.This research presents the design of an innovative off-axis three-mirror optical system characterized by an“annular contour”,facilitated through a methodical,gradual optimization strategy concentrating on the field of view and surface morphology.The proposed system boasts a focal length of 2000 mm,a field of view spanning 5°×5°,an F-number of 12.5,and an external envelope circle diameter measuring 750 mm.Integral to this design is the employment of XY polynomial freeform surfaces for the primary and tertiary mirrors,and Zernike polynomial freeform surfaces for the secondary mirror.These selections were motivated by their capacity to minimize aberrations and enhance the system´s imaging performance.By applying the surface shape parameters of these freeform surfaces,we conducted simulations to generate two-dimensional sagittal height maps for each of the three mirrors,thus facilitating a rigorous analysis of the optical system´s theoretical capabilities.The results from this design process indicate that the imaging quality of the system aligns closely with the diffraction limit.Specifically,the maximum Root Mean Square(RMS)spot diameter across all fie

关 键 词：光学设计 离轴三反 自由曲面 大视场 XY多项式 ZERNIKE多项式 空间相机 

分 类 号：O439[机械工程—光学工程]