一种新型双光栅光谱仪光学系统设计与优化

An improved method for optical system design and optimization of double grating spectrometer

由于所需测量的光谱范围较宽(276~700 nm),而CCD探测器的接收面尺寸较小(14.3 mm×10.5 mm),根据所选用的平面光栅元件参数,采用传统的车尔尼-特纳型结构是无法满足的。基于该结构,利用光线相对光栅的入射角和衍射角与光栅转角的关系,提出了使用两块反射式平面光栅进行光谱分离的方法。通过理论计算,确定了两段光谱范围和两光栅的旋转及俯仰角度,采用ZEMAX软件建立多重结构,分别设置两块光栅的位置和波长参数,对光学系统进行了模拟分析和优化。结果表明,在像面上得到了两条谱面线展宽为14mm,中心间距8mm的光谱带,光谱分辨率优于1nm,各像差得到了充分校正,满足设计指标要求,很好地解决了宽光谱和探测器接收面尺寸之间的矛盾。

Due to the onconflict between the wide spectral range of measuring (276-700 nm) and the limited imaging area of CCD detector (14.3 mm ×10.5 mm), classical Czerny-Turner structure was not able to meet the requirements of design. Based on it, an innovative method applying two uniform plane diffraction gratings to separate the whole spectral range into two different sections was presented. The two separate spectral range, rotation and tilt angles of two gratings were obtained through theoretical computation. The optical software ZEMAX was used to simulate and optimize the optical system by multiple configuring parameters. The simulation results show that two spectral bands are detected on the imaging plane. Their spectrum width is 14 mm respectively, and the center distance between them is 8 mm. The spectral resolution is less than 1 nm and the aberration is substantially corrected. It indicates that the method is a good solution for the situation of wide spectral measurement range and limited imaging dimension of CCD detector in the meanwhile.