大口径分光计中棱镜色散光谱线弯曲的测定

Measurement of the bending of spectrum lines in large aperture prism spectrometer

利用几何光学方法分析了大口径分光计光中的光谱线弯曲现象,发现不平行于棱镜主截面的光线引起了光谱线的弯曲.如果采用与光线的倾角有关的等效折射率,不平行于主截面的光线在主截面内的投影也可以看成在按折射定律传播的光线,在此基础上得到了光谱线曲率的计算公式.用照相法实测了光谱线的曲率,修正像差导致的误差后的测量结果与理论值符合较好.

The bending of spectrum lines in large aperture optical spectrometer was analyzed based on geometric optics .The bending was caused by the incident rays that were not parallel to the major plane of the prism .T he projection of these off‐plane rays could be treated as in‐plane rays if an incli‐nation‐dependent effective index of refraction was used .From this point of view ,the curvature of the spectrum line was measured by the photographic method .After the error due to aberration was care‐fully eliminated ,the measured curvature agreed with the calculated value quit well .