消偏振分光棱镜的设计与性能分析

Design and characteristics analysis of non-polarizing beam splitters

为消除光线倾斜入射所产生的偏振效应,介绍了基于布儒斯特条件的消偏振效应分光棱镜设计方法,选用3种常见的薄膜材料,氧化铝和氟化镁2种材料的p偏振的有效折射率相等,在特定的波长处实现2种偏振态的反射率相等,可达到消偏振的效果.改善膜层分布实现了优化特定波长域的反射率,研究了利用双折射特性实现的消偏振分光棱镜的角度特性,提供了反射为30%、50%、70%这3种设计方案,入射角偏离2°引起的偏振分离小于5%.

Abstract： A method has been developed for a non-polarizing beam splitter which utilizes a Brewster condition in a cube that eliminates polarization effects caused by the oblique incidence of light. This design concept was based on the use of quarter-wave layers of three conventional materials which were paired to have the same effective indices of p polarization. In this way they produce identical reflectance of two polarizations at a specified wavelength. Performance outside this wavelength was improved by altering the order of layers. Analysis of characteristics at various angles for non-polarizing beam splitters with birefringent properties was also conducted. Three designs with 30%, 50% and 70% reflectance were achieved with polarization separation less than 5% in the 2°region.