格兰-泰勒棱镜消光比分析

Analysis of extinction ratio of a Glan-Taylor prism

利用折射定律和菲涅耳公式,采用光线追迹的方法,推导了格兰-泰勒棱镜的透过率与发散光束入射的方位角、入射角及棱镜结构角之间的计算公式,并指出与棱镜消光比的关系。通过Matlab仿真,分析了全方位角范围内,棱镜的消光比特性以及消光比随入射角和结构角的变化关系。仿真结果发现,在垂直棱镜光轴的方位上,消光比不受入射角大小的影响,且消光比随棱镜结构角的增大而变差。理论计算结果与实际系统出现的问题相符,验证了理论公式的正确性,解释了工程项目出现的问题,对格兰-泰勒棱镜的设计与应用具有一定的指导意义。

The calculation formula of Glan-Taylor prism′s transmittance between emanative lights′azimuth, incident angle and structure angle of prism was obtained by using refraction law and Fresnel formula as well as the ray-tracing method. The relationship between the extinction ratio and transmittance was indicated. By computer simulation of Matlab, the characteristic of extinction ratio in the whole azimuth was analyzed; the extinction ratio′s transformation relationship along with incident angle and structure angle was investigated. From simulation results, we discover that the extinction ratio is unacted on the incident angle when the angle is in the vertical azimuth of prism′s optical axis. And the ratio becomes bad with increasing of the structure angle. The theoretical results are in good agreement with problems appeared from practical system which verifies its correctness, and it explains the problem in project item. The work of this article has great guiding significance in the design and use of Glan-Taylor prism.