基于Zemax软件的光栅光谱仪分辨能力仿真实验

Simulation of the Resolving Ability of the Grating Spectrometer Using Zemax Software

利用Zemax光学设计软件,可以分析衍射级次、光栅常数、入射狭缝、出射狭缝和光学元件性能等对光栅光谱仪分辨率的影响。在仿真过程中,用光线追迹方法,直观地以点列图的形式展现衍射方程各参数、入射和出射狭缝宽度对衍射效果的影响。结果表明,入射狭缝和出射狭缝都对光谱仪分辨能力具有较大影响,狭缝越大,光谱分辨率越低。光谱仪中的准直镜和聚焦镜的焦距影响系统整体尺寸和分辨率。两镜固有的剩余球差、色差、慧差降低光谱分辨率,采用非球面镜、非球面反射镜可以适当改善像差,提高系统分辨率。用WGD-8A光栅光谱仪实测钠双黄线光谱,测得光谱随入射狭缝和出射狭缝变化的曲线变化与软件仿真结论一致。

The resolving ability of the grating spectrometer is effected by some parameters,such as the grating constant,order of diffraction,entrance slit width,exit slit width and the performance of the optical elements,and so on.The resolving power of transmission spectrometer is analyzed using Zemax software.Using the sequence ray tracing method,the Spot Diagram shows the light distribution on each surface,especially the image surface to observe the diffraction results with the changed parameters of grating constant,order of diffraction.The larger entrance slit or exit slit might reduce the resolving power of the grating.The used optical elements still have some aberrations,such as spherical aberration,coma,astigmatism and so on.These aberrations would reduce the resolving power.The resolving power can be improved by using the aspheric lens or aspherical mirror.The double yellow lines of sodium lamp are measured using the WGD-8 A spectrometer with the changed entrance slit and exit slit width.The measured spectrums are agreed with the analysis results using the Zemax software.