双路四通道同时干涉成像光谱仪

Dual Four-Channel Simultaneous Interference Imaging Spectrometer

双路四通道同时干涉成像光谱仪以视场光阑代替狭缝,无旋转和移动部件,通过消色差分光棱镜和Savart偏光镜将入射光分为四对相干光束,同时在探测器上获取四幅不同偏振信息的目标图像,进而利用傅里叶变换运算并对数据进行处理得到偏振光谱图像。分析系统结构和原理得出不同偏振状态下的干涉强度表达式,四幅干涉图相加获取目标图像的总强度,同一Savart偏光镜的干涉强度相减获得纯干涉条纹,将两纯干涉条纹进行加减运算可降低系统的背景噪声,提高了系统信噪比。在考虑晶体色散关系的基础上分析讨论了光程差随波长、入射角、入射面与晶体主截面夹角以及晶体厚度的变化,在傍轴条件下设计出横向剪切量、成像透镜焦距和晶体厚度的具体参数,实现了高光谱分辨率成像,为新型干涉成像光谱仪的设计与应用提供了一种新方案。

The dual four-channel simultaneous interference imaging spectrometer,using a field view stop instead of the slit filter,without rotating and moving parts,divides the incident light into four coherent beams through achromatic beam splitters and Savart polariscopes.Four interference fringes with different polarization informations are obtained in the detectors.Spectral images can be acquired with the Fourier transform algorithm and image processing.Expressions for interference intensities are presented.The total intensity of the target image is obtained by summation of the four interferograms.The difference between interference intensities in the same CCD is equivalent to the pure interference fringes.The difference or summation of two pure interference fringes of different CCDs is equivalent to the single-channel interference fringes,which improves the signal-noise ration of the system.The optical path differences varying with wavelength,incidence angle,incident azimuth angle and Savart polariscope thickness are described based on the analysis of dispersing result from crystal.Considering the paraxial approximation,the fringe distribution is analyzed,and then the lateral displacement and the focal length of the lens are designed.The thickness of the crystal is discussed.This spectrometer is characterized by the simultaneous acquisition of four target images with different polarization informations.The background intensity is suppressed,and the spatial filtering and the jitter noise caused by moving or rotating parts are avoided.The results show that high resolution imaging is realized.This study provides a new solution for the design and application of interference imaging spectroscopy.