改进的宽谱段车尔尼-特纳光谱成像系统设计

摘要

A modified Czerny-Turner spectral imaging system was developed based on aberration theory to minimize the large astigmatism in classical Czerny-Turner spectrometers. The astigmatism from a plane grating placed in the divergent light beam was used to compensate the astigmatism from an objective lens. The broadband astigmatism corrected simultaneously conditions were deduced, and the a-stigmatism was corrected in a wide spectral region. The principle and method of astigmatism correction were analyzed in detail, and the initial parameter computing was programed. As an example,a Czerny-Turner imaging spectral system operating in 540 - 780 nm was designed. The ray tracing and optimization for the spectral imaging system were performed with ZEMAX-EE software. The analyzed results demonstrate that the total field-of-view modulation transfer function is higher than 0. 52 in the whole working spectra. The system shows good imaging quality due to the astigmatism to be corrected in the wide spectral region synchronously. Obtained results prove the feasibility of the modified method.%针对传统的车尔尼-特纳光谱仪像散较大的缺点,基于像差理论,提出了一种改进的车尔尼-特纳光谱成像系统.将平面光栅置于发散光中,利用平面光栅产生的像散来补偿物镜产生的像散.推导出了宽谱段像散同时校正条件,实现了宽谱段像散的同时校正.具体分析了像差校正的原理和方法,编制了初始结构快速计算程序.作为实例,设计了一个谱段为540～780 nm的宽谱段像散同时校正车尔尼-特纳光谱成像系统,利用光学设计软件ZEMAX-EE对该光谱成像系统进行了光线追迹和优化设计,并对设计结果进行了分析.结果表明,全视场调制传递函数在整个工作波段均达到0.52以上,实现了宽谱段像散的同时校正,并获得了良好的成像质量,满足了设计指标要求,结果也证实了所提出的改进方法是可行的.