unusually

Refraction regularity of extraordinary ray in uniaxial crystal with arbitrarily oriented optical axis;

单轴晶体光轴任意取向时非寻常光的折射规律

In the case of optical axis of uniaxial crystal being parallel with the incident plane, the angle of refraction of extraordinary ray are calculated by using Fermat's principle.

在单轴晶体的光轴与入射面平行的情形下用费马原理计算非寻常光光线的折射角，然后就怎样定义非寻常光作些讨论，最后在单轴晶体的光轴任意取向的普遍情形下给出计算非寻常光光线折射方向的公式。

In situation the optical axis of an uniaxial crystal lies in the plane of incidence，an equation determining the relationship between the angle of incidenee and that of refractionof extraordinary rays is derived by using Fermat s principle，An illustrative numerical examplefor CaCO_3 crystal is given.

本文由费马原理导出了单轴晶体中非寻常光（ｅ光）的折射角满足的方程，并以方解石为例给出了数值计算结果。