工作波段覆盖近紫外到近红外波的消偏振分色片的设计与研制

Design and Fabrication of a Depolarizing Dichroic Beam Splitter Working in Band from Near-UV to Near-Infrared

介绍了宽波段成像光谱仪系统中一种工作波段为0.35-1.7μm的消偏振分色片的设计与研制。根据成像光谱仪的工作特点,利用分色片将近紫外、可见波段和近红外波段光谱进行高效分离,分别进入各自焦面,并被不同探测器接收。选择两种光学薄膜材料,利用四个反射堆实现了近紫外到可见光波段的高效反射;通过调整反射堆的次序,解决了近紫外波段材料吸收造成的偏振灵敏度高的难题;通过非规整膜层的匹配平滑了透射波段的光谱。分色片反射波段和透射波段的光学效率分别达到了97%和91%以上,反射波段的偏振灵敏度控制在1.5%以内。

A depolarizing dichroic beam splitter,which works in the waveband from 350 nm to 1700 nm is designed and fabricated for broadband imaging spectrometers.Based on the working characteristics of the imaging spectrometer,the spectra in near-UV,visible and near-infrared bands are effectively separated,and the signals spread to their respective focal planes and are received by different detectors,respectively.In order to achieve high reflectance from near-UV to visible,two thin film materials are selected to structure four reflectance stacks.The linear polarization sensitivity is hard to control because of absorption of the thin film materials,and the problem is solved by adjusting the order of stacks.The spectra in the transmission band are smoothed by the non-regular film matching.The optical efficiencies in the reflection and transmission bands are as high as 97% and 91%,respectively,and the linear polarization sensitivity is lower than 1.5%.