紧凑式离轴三反光学系统设计

Design of compact off-axis triple mirror optical system

为解决地球遥感观测和星载激光雷达探测等领域对空间光学系统尺寸小型化、结构紧凑和高分辨率的要求,本文设计了一种基于Zernike自由曲面的紧凑式离轴三反系统,同时满足了长焦距、小畸变和宽工作波段的要求。该系统采用非对称、近圆形布局的离轴三反光学系统,并在第三反射镜采用了自由曲面的设计,通过在Zemax软件中设置适当的优化目标和方法,对光学系统进行设计优化。最终该系统有效焦距为800 mm,F数为4,视场角为12°×6°,畸变小于1%,工作波段覆盖可见光及近/中红外波段,在400 km轨道高度实现了1.5 m的地元分辨率(可见光)和2.5 m的地元分辨率(近红外),地面幅宽为80 km×40 km。并进行了系统像差、点列图、MTF等性能指标评估的分析与验证,结果表明该设计方案带来了高分辨率并提升了信息获取能力。

In order to meet the requirements of miniaturization,compact structure and high resolution of the space optical systems in the fields of Earth remote sensing observation and spaceborne Lidar detection,this paper designs a compact off-axis triple inverse system based on Zernike free-form surface,which simultaneously meets the requirements of long focal length,small distortion and wide working band.The system adopts an off-axis triple inverse optical system with the asymmetric and nearly circular layout,and the third mirror of the system adopts the free-form surface design.By setting appropriate optimization objectives and methods in Zemax software,the design of the optical system is optimized.Finally,the effective focal length of the system is 800 mm,the F-number is 4,the field of view is 12°×6°,and the distortion is less than 1%.The working band covers the visible and near/middle infrared bands,and the ground element resolutions of 1.5 m(visible light)and 2.5 m(near infrared)can be achieved at the orbit height of 400 km,and the ground width is 80 km×40 km.The analysis and verification of system aberration, dot plot, MTF and other performance indexes are carried out. The results show that the designscheme brings the high resolution and improves the information acquisition ability.