转镜式傅里叶变换光谱仪光程差非线性的研究

转镜式傅里叶光谱仪中，转镜的转动形成光程差的非线性。光程差非线性是转镜材料和工作角选择时要考虑的重要因素，通过对它的研究，可以为工程实践提供指导，为进一步研究奠定基础。通过输入单色光时的情况对干涉图进行研究，发现光程差非线性使干涉图的周期发生变化；通过和光程差线性系统的仪器函数比较对复原光谱进行研究，发现非线性给复原光谱带来了噪声和波数漂移。由于光程差的变化是已知的，在光谱复原时，用非线性的光程差代替傅里叶变换中的光程差，就可以对光程差非线性进行补偿。计算机仿真实验的结果表明，这种方法效果明显，经补偿后复原光谱中光程差非线性带来的噪声基本消失。

Studies on Nonlinearity of Optical Path Difference of Rotary Fourier Transform Spectrometer

High-speed rotary Fourier transform spectrometer has nonlinearity of optical path differences (OPD) because of refractor's rotating. Nonlinearity is an important aspect to be considered when material of rotor and scan angle are chosen. It is studied to direct engineering and more studying here. Its effect on interferogram and reconstructed spectrogram are discussed. Nonlinearity of OPD can cause variance periodic of interferogram. And it introduces noise and wave number shift of reconstructed spectrogram. Since OPD can be calculated while refractor rotating, Nonlinear OPD can be replaced with corresponding linear OPD in Fourier Transform to compensate the nonlinearity of OPD. The computer simulation testifies this method being effective. Noise caused by nonlinearity in reconstructed spectrogram disappears after being compensated.