洛匈棱镜的正反向特性

给出了洛匈棱镜正、反向使用时分束角的精确表达式。从理论上证明,对任意合理的结构角及主折射率值来说,洛匈棱镜反向使用时的分束角小于正向使用时的分束角。研究了在锥光入射条件下洛匈棱镜中的e光和o光的传播方向、折射率、主平面、偏振方向等问题。证明了洛匈棱镜正向使用时第二块晶体中无偏折的光波只含有o光,参考圆圆周上各点光波的主平面相互平行,通过一个检偏器后可以实现消光;洛匈棱镜反向使用时,第二块晶体无偏折的光波同时包含了o光和e光,参考圆圆周上各点光波的主平面沿参考圆的径向,e光和o光的偏振方向分别沿径向和垂直于径向,通过检偏器后形成锥光干涉现象,不能消光。

Characteristics of the Rochan prism in forward-use and backward-use

The accurate expressions of separation angle of the Rochan prism for forward-use and backward-use are given.It is proved theoretically that the forward separation angle is larger than the backward separation angle for any reasonable structure angle and principal refractive indexes.The propagation directions,the refraction indexes,the principal plane and the vibration directions of the ordinary wave and the extraordinary wave in the Rochan prism are investigated as incidence light is conoscopic beam.In the second crystal it is only o wave is free from refraction in case of the Rochan prism in forward-use,all the principal planes of the waves which pass through different points of the same circle are parallel.Thus extinction can be achieved successfully by an analyzer.In the second crystal the waves which are free from refraction contains both o wave and e wave in case of the Rochan prism in backward-use,the principal plane of the wave which passes through a point of the circle is in the radial direction,the vibration direction of the e wave is along the radial direction and the vibration direction of o wave is perpendicular to the radial direction.Thus the beam emerging from an analyzer causes conoscopic interference as the Rochan prism is in backward-use,and extinction can not be obtained by a polarizer.The Rochan prism is not appropriate for backward-use.