A simple and comprehensive electromagnetic theory uncovering complete picture of light transport in birefringent crystals

作者：Jianbo Pan, Jianfeng Chen, Lihong Hong, Long Li, Zhiyuan Li · 发表于：Chinese Physics B · 年份：2021 · DOI：10.1088/1674-1056/ac4747 · 被引用次数：8 · 研究领域：Photorefractive and Nonlinear Optics、Optical and Acousto-Optic Technologies、Photonic and Optical Devices

Birefringence production of light by natural birefringent crystal has long been studied and well understood. Here, we develop a simple and comprehensive rigorous electromagnetic theory that allows one to build up the complete picture about the optics of crystals in a friendly way. This theory not only yields the well-known refraction angle and index of ellipse for birefringence crystal, but also discloses many relevant physical and optical quantities that are rarely studied and less understood. We obtain the reflection and transmission coefficient for amplitude and intensity of light at the crystal surface under a given incident angle and show the electromagnetic field distribution within the crystal. We derive the wavefront and energy flux refraction angle of light and the corresponding phase and ray refractive index. We find big difference between them, where the phase refractive index satisfies the classical index of ellipse and Snell’s law, while the ray refractive index does not. Moreover, we disclose the explicit expressions for the zero-reflection Brewster angle and the critical angle for total internal reflection. For better concept demonstration, we take a weak birefringent crystal of lithium niobate and a strong birefringent crystal tellurium as examples and perform simple theoretical calculations. In addition, we perform experimental measurement upon z -cut lithium niobate plate and find excellent agreement between theory and experiment in regard to the Brewster an...