转镜式光谱仪端反射镜误差容限分析

系统分析了当转镜式干涉光谱仪端反射镜发生倾斜，致使反射光束偏转时对干涉图的影响.发现光束偏转带来的误差分为三部分：1）光束偏转导致整体增加的恒定光程差；2）垂直光轴方向因不同光线而引入的偏移光程差；3）光束中心相对于光轴的偏移量.干涉强度中的有效信号减小，同时直流分量不变，因此信噪比降低.最后从调制度和相位误差角度给出了端反射镜倾斜误差容限并讨论了减小干涉图受光束偏转影响的方法.

The Tolerance of the End Mirror tilting in High Speed Rotary Spectrometer

In this paper, the tolerance of the end mirror(plane mirror)tilting in high speed rotary spectrometer is analyzed systematically by means of modulation depth and phase error. It is found that the changes resulted from the tilting of the end mirror was made up of three parts:1) the constant OPD that reflective light increases;2) the increased OPD concerning different ray along the perpendicular direction to light axis;3)the moving distance of the light beam center to light axis. The SNR of the output is reduced by these changes. The formula of changed interferogram intensity is given. Methods to avoid the problems resulted from the tilting of the end mirror are also discussed.