转镜式傅里叶变换光谱仪光程差非线性的拟合法补偿

Compensating Nonlinearity of Optical Path Difference of Rotary Fourier Transform Spectrometer with Fitting Interferogram

转镜式傅里叶变换光谱仪中光程差非线性带来了干涉图周期变化和相位误差,对非线性的拟合法补偿利用采样得到的干涉图进行重构,得到不含相位和周期误差的干涉图,再按照均匀采样函数对干涉图进行二次采样,消除非线性光程差对复原光谱的影响.经过二次采样的干涉图不含周期和相位误差,可以直接使用现有的软件进行光谱复原.计算机仿真实验证明这种方法行之有效,且利用4次多项式拟合干涉图效果更好.

Because of rotating reflector or refractor,there is nonlinearity of Optical Path Difference（OPD） in high-speed rotary FT-Spectrometer. Nonlinearity which was studied to direct engineering in this paper is a very important aspect to be considered in designing system. In nonlinear OPD system,interferogram is sampled linearly, which brings interferogram phase and period error. The case corresponds to the interferogram without those errors sampled nonlinearly. Interferogram without phase and period errors can be reconstructed with those interferogram data sampled in unequal intervals through fitting polynomial. Then the reconstructed interferogram is sampled in equal intervals. Those data are used to reconstruct spectrum without noise caused by OPD nonlinearity. Computer simulation shows this method is effective, and fits interferogram with quartic polynomial well. The method is also effective in other nonlinear OPD systems.