太阳极紫外成像仪光学系统研制

Development of an optical system for solar extreme ultraviolet (EUV) imaging telescope

文章针对太阳观测的物理需求,完成了角分辨率优于1″的太阳极紫外成像仪光学系统的研制.该系统采用经典卡塞格林光路结构.使用ZEMAX软件对所设计的光学系统进行分析,结果表明其在视场角±17′内的光斑均位于1个像素(13.5μm×13.5μm)范围内.在光学系统研制完成后,采用一种间接方法来检测光学系统角分辨率:首先利用ZYGO干涉仪检测光学系统的波像差,再根据检测的出瞳面上的波像差结果,计算出光学系统在19.5 nm工作波段的点扩散函数;结果表明,光学系统在视场角±17′的范围内,像素环围能量比均优于80%,在19.5 nm波段的角分辨率优于1″.

In this paper,an optical system with an angular resolution of 1″for the solar extreme ultraviolet(EUV)imaging telescope is developed.A classical Cassegrain optical path structure in used in the system.The calculation results by the ZEMAX software show that the spot within the field of view of±17′is located in one pixel(13.5μm×13.5μm)range.An indirect method is used to test the angular resolution of the optical system.Firstly,a ZYGO interferometer is used to detect the wavefront aberration of the system.Then,the point spread function with a working band of 19.5 nm is calculated based on the wavefront aberration results on the exit pupil plane.It is shown that the energy ratio for the pixel enclosure circle is better than 80 percent in the field of view of±17′,which indicates that the angular resolution in the band of the optical system of 19.5 nm is better than 1″.