影响Czerny-Turner结构像散校正的因素

针对宽波段Czerny-Turner结构像散校正存在的问题,分析了影响光学系统像散校正的主要因素。基于发散光束照射平面光栅的像差理论,应用Matlab软件模拟分析了光学系统产生像散的原因和相应抑制方法的不足。讨论了了准直镜离轴角与聚焦镜离轴角的角度差值α和光学系统像散S之间关系,理论模拟了α取不同值时,宽波段C-T结构的全波段像散校正情况。为了验证理论分析的正确性,设计了光谱段为900~1 700nm的消像散型光学系统,利用光学设计软件Zemax对该波段的光学系统进行了光线追迹和设计优化,并对设计结果进行处理和分析。结果显示:随着角度差值的逐渐增大,短波波段像散校正能力越来越强,像散校正能力提高了1.6倍左右;长波波段像散束缚能力越来越弱,像散校正能力平均降低了1.27倍左右。得到的结果表明:角度差值的合理选取可以为宽波段Czerny-Turner结构的像散校正提供理论指导。

Influence factors of Czerny-Turner edge band astigmatism correction

To improve the weak correcting capacity of a wide band Czerny-Turner structure, the influence factors on the astigmatism correction of an optical system were analyzed. The Matlab software was used to simulate and analyze the reasons that the astigmatism was produced and the traditional method could not suppress the astigmatism. Then, the dependence of the angle difference α between the off-axis angle of collimator mirror and the off-axis angle of focusing mirror on the astigmatism S of the optical system was discussed. The astigmatism correction of wide band Czerny-Turner structure was simulated at different α values. To verify the validity of the theoretical analysis, an astigmatic Czerny-Turner system ranging from 900 to 1 700 nm was designed, the Zemax was used to perform the ray tracing and optimal design and the design results were processed and analyzed. The simulation results demonstrate that the shortwave band astigmatism correction ability is getting stronger with increasing the difference angle, which may achieve about 1.6 times on increase. However, long wave band astigmatism correction ability is more and more weak, which may reduce about 1.27 times on average. It suggests that the reasonable selection of the difference angle can provide the theoretical guidance for correcting the astigmatism of wide band Czerny-Turner structures.