一种提高静态傅里叶干涉仪光谱分辨率的方法

为了在不改变静态傅里叶变换干涉具尺寸的前提下提高光谱分辨率,设计了正交斜楔型静态傅里叶变换干涉具,采用两个正交的等效斜楔形成连续的光程差变化.通过推导传统干涉具与正交斜楔型干涉具的光程差函数,设计了采用正交斜楔型干涉具增加有效探测长度,从而提高光谱分辨率的方法.经仿真计算,正交斜楔型干涉具的最大光程差为0.323 4 mm,比传统干涉具的0.080 8 mm大4倍左右,即光谱分辨率提高了4倍.实验证明,由于正交斜楔的探测原理使干涉具边缘的干涉条纹产生畸变,故要对干涉条纹进行边缘切除及滤波,给出了切除大小的计算公式.采用WQF520型光谱仪进行对比实验,检测800 nm的激光,该干涉具误差小于1 nm.该方法可有效地提高静态傅里叶变换干涉具的光谱分辨率.

A Method to Improve Spectral Resolution for the Static Fourier Interferometer

In order to improve spectrum resolution with the same size of the static Fourier transform interferometer,an orthogonal-wedge static Fourier transform interferometer is designed,which is made up by the two orthogonal-wedge for continuous optical path difference.According to the derivation of the optical path difference function with the tradition static Fourier transform interferometer and the orthogonal-wedge static Fourier transform interferometer,the structure of the two orthogonal-wedge is designed to increase the effective distance of detection for improving spectrum resolution of static interferometer.The simulation results show that the maximum optical path difference of the orthogonal-wedge interferometer is 0.323 4 mm,which is four times better than the traditional interferometer with 0.080 8 mm (optical path difference).Experimental results show that the orthogonal-wedge interferometer has the distortion of the interference fringes as a result of its detection principle,so it needs to be removed and filtering of the edge of the interference fringes.Using the WQF520 type spectrometer to comparative experiment for 800nm laser,the orthogonal-wedge interferometer error is less than 1 nm.This method can effectively improve the spectral resolution of the static Fourier transform interferometer.