基于离轴三反光学系统的高分辨率中阶梯光栅光谱仪

High-Resolution Echelle Grating Spectrometer Based on Off-Axis Three-Mirror Reflective Optical System

基于离轴三反光学系统和多列线阵探测器,设计了一种具有宽波段高光谱分辨率的中阶梯光栅光谱仪。首先,以仪器性能指标为约束优化中阶梯光栅的结构参数,使光栅在保证高色散的同时将宽工作波段折叠重合在较小的光谱级次内,并采用多列线阵探测器采集信号。然后,以离轴三反光学系统作为会聚镜,以离轴抛物镜作为准直镜,实现了高色散宽自由光谱的像差校正。最终,设计的中阶梯光栅光谱仪工作波段为400~900 nm,F数为4.5,光谱分辨率在402.31,541.82,870.48 nm时分别为0.003,0.004,0.005 nm,系统体积为380 mm×325 mm×230 mm。

A wide-band high-resolution echelle grating spectrometer is designed on the basis of an off-axis three-mirror reflective optical system and a multi-column linear array detector in this paper.First,the structural parameters of the echelle gratings are optimized with the instrument performance indicators as constraints so that the gratings can fold and overlap the wide working band within a small spectral order while ensuring high dispersion.The multi-column linear array detector is used for signal acquisition.Then,for the aberration correction of the wide free spectral region with high dispersion,the off-axis three-mirror reflective optical system is used as the focusing mirror and the off-axis parabolic mirror is used as the collimating mirror.The working band of the designed echelle grating spectrometer is 400--900 nm,and the F number is 4.5.The spectral resolution is 0.003,0.004,and 0.005 nm at 402.31,541.82,and 870.48 nm,respectively,and the system volume is 380 mm×325 mm×230 mm.