光谱仪中球面聚焦反射镜和凹面全息光栅像差互补的一体化设计

Integrated Design to Complement Aberrations of Spherical Focusing Mirrors and Concave Holographic Gratings in Spectrometers

为了兼顾光源聚焦镜引入的像差对光谱仪器分辨率和信噪比的影响,提出了消像差凹面全息光栅和聚焦反射镜一体化设计方法。建立了包含聚焦镜和凹面全息光栅的像差分析物理模型,推导了像差系数表达式,构造了像差校正目标函数,经优化得到设计结果。在一体化设计中,针对臂长为170.3mm、基底曲率半径为170.2mm的单色仪光栅,通过反向增大全息光栅像散项,补偿聚焦镜引入的轴外像差。与传统设计方法相比,该方法的像面点列图的均方根尺寸在子午方向由86μm减小到81μm,弧矢方向由765μm减小到167μm,提高了系统的消像差能力,为凹面光栅光谱仪器的光学系统设计提供了新的思路。

A design method integrating the aberratiomcorrected concave holographic grating and focusing mirror has been proposed, and the effect of the aberration of the optical source focusing mirror on the resolution and signal to noise ratio of the spectrometer is considered. A physical model of aberration analysis including a focusing mirror and a concave holographic grating has been built, an aberration coefficient expression is derived, a corrected aberration objective function is constructed, and an optimized design is finally obtained. In the integrated design, aiming at the monochromator grating in which the arm length is 170. 3 mm and the curvature radius of the basement is 170.2 mm, the off-axis aberration caused by the focusing mirror is compensated through reversely increasing the holographic grating astigmatism. Compared with that of the traditional design, the root mean square size of image spot diagram decreases from 86 μm to 81 μm in the meridional direction, and from 765 μm to 167 μm in the sagittal direction. This method improves the capability of correcting system aberration and provides new design concepts for the optical system of concave grating spectrometers.