反射率对入射角扫描测定单轴晶体的折射率

Refractive Indices Measurements of Uniaxial Crystal by Reflectivity Scan to Incident Angle

通过分析波矢沿任意方向的单轴晶体的折射率,在光轴位于入射面内时,给出了入射光分别为s光和p光的反射率拟合函数。利用改进的反射率扫描仪,测量了CaCO3晶体的s光和p光反射率随入射角变化情况,由理论拟合获得单轴晶体的两个主折射率,分别为no=1.6559和ne=1.4851。这种方法不需要对样品进行加工,其精度达到0.0001。另外,对于晶体光轴未知的情况,采用改进的布儒斯特技术分别测出三个晶体表面的布儒斯特角,由此可以确定光轴的方向。

The refractive indices along arbitrary wave vector direction were analyzed in uniaxial crystal with buried optical axis. When the optical axis is in the plane of incidence,the reflectivity fitting functions of s- and p-polarized light are presented. Then, the changes of reflectivity with incident angle have been measured with a modified reflectivity scanner, in s- and p-polarized light for CaCOa crystal respectively. Using a fitting of experimental data based on reflectivity fitting functions the two principal refractive indices were obtained, no = 1. 6559, and ne = 1. 4851. This technique does not need sample machining, and the accuracy reaches 0. 0001. Otherwise,in the case of unknown optical axis, the optical axis direction was determined with the Brewster angles of the three crystal surfaces measured by using the improved Brewster angle technique.