Optical design of Schwarzschild imaging spectrometer with freeform surfaces

作者：Xing-Wei Liu, Jinsong Zhou, Li-Dong Wei, Lei Feng, Juan-Juan Jing, Xiao-Ying He, Lei Yang, Ya-Can Li · 年份：2021 · DOI：10.1016/j.optcom.2020.126495 · 被引用次数：13 · 研究领域：Physics

Abstract The classical Schwarzschild imaging spectrometer consists of a plane grating and three spherical mirrors. It suffers from a slow optical speed and a small field of view (FOV). Furthermore, astigmatism aberration is present in the conventional configuration due to the dispersion of the plane grating. In this study, a group design method was developed to design a Schwarzschild imaging spectrometer with freeform surfaces. The group design method corrects the astigmatism aberrations in the collimating system and focusing system separately and gives a higher-performing initial structure. To achieve fast optical speed and a larger FOV, freeform surfaces are used to correct the large off-axis aberration. Based on this method, a Schwarzschild imaging spectrometer with a fast optical speed (F/2) and large FOV (32 mm slit) using freeform surfaces is proposed. The initial structure design, optimization procedure, and tolerance analysis are described in detail. The design results indicate that good optical performance and manufacturability of the system are obtained.