空间静态偏振调制干涉光谱系统的设计与仿真

Design and simulation of spatial static polarization modulation interferometric spectroscopy system

为了更好地获取目标物的光谱偏振信息,设计了一套空间静态偏振调制干涉光谱系统。该系统结合了空间外差光谱和偏振光谱强度调制技术,只需一次采样便可同步获取目标的分辨偏振光谱信息以及高光谱分辨率的Stokes矢量偏振光谱。首先从偏振光谱强度调制和空间外差光谱仪的光学理论入手,对该系统的光谱信息采集和偏振信息调制解调过程进行数学推导。然后根据调制模块中高阶相位延迟器的厚度与光谱仪带宽之间的对应关系,发现现有的光谱仪带宽过窄,导致延迟器厚度过大,无法适应宽波段的光谱测量需求。结合延迟器厚度与光谱复原分辨率的约束关系,在极限厚度下得出了空间外差光谱仪的最小拓宽光谱范围。最后根据改进的参数匹配设计,对探测过程进行了计算机数值模拟。研究结果表明:在空间外差光谱仪的最小拓宽工作波段内,对CCD探测器记录的干涉图进行基于傅里叶变换的解调处理,能够高保真地复原输入光信号的Stokes参量的偏振光谱信息,从而验证了该系统的可行性。

In order to better obtain hyperspectral polarization information,a spatially static polarization modulation interferometric spectroscopy system is designed.The system combines spatial heterodyne spectroscopy and polarization spectral intensity modulation technology,and can synchronously detect the resolved polarization spectral information of the goal and the high spectral resolution Stokes vector polarization spectrum with only one sampling.In the first place,based on the optical theory of polarization spectral intensity modulation and spatial heterodyne spectrometer,the mathematical formulas are deduced for the spectral information acquisition and polarization information modulation and demodulation process of the system.Then,according to the corresponding relationship between the thickness of the high-order phase retarder in the modulation module and the bandwidth of spectrometer,it is found that the bandwidth of the existing spectrometer is too narrow,resulting in the thickness of the retarder being too large,which cannot adapt the requirements of wide-band spectral measurement.Therefore,combined with the constraint relationship between the retarder thickness and the spectral restoration resolution,the minimum broadened spectral range of the spatial heterodyne spectrometer is obtained under the limit thickness.Finally,according to the improved parameter matching design,the computer numerical simulation of the detection process is conducted.The research results show that in the minimum widening working band of the spatial heterodyne spectrometer,the interferogram recorded by the CCD detector can be demodulated based on Fourier transform,and the polarization spectrum information of the Stokes parameter of the input optical signal can be restored with high fidelity,thus verifying the feasibility of the system design.