Shen Siyuan, Ruan Zhaohui, Yuan Yuan, Tan Heping
School of Energy Science and Engineering, Harbin Institute of Technology, 92 West Dazhi Street, Harbin 150001, P. R. China.
Key Laboratory of Aerospace Thermophysics, Ministry of Industry and Information Technology, Harbin Institute of Technology, 92 West Dazhi Street, Harbin 150001, P. R. China.
Nanophotonics. 2021 Nov 1;11(1):21-32. doi: 10.1515/nanoph-2021-0459. eCollection 2022 Jan.
The generalized Snell's law dictates that introducing a phase gradient at the interface of two media can shape incident light and achieve anomalous reflection or refraction. However, when the introduced phase gradient is realized via the scattering of nanoparticles in the metasurfaces, this law needs to be modified; certain conditions need to be met when the law is established. We present the conditions for establishing the "generalized Snell's law of refraction" in all-dielectric metasurfaces under the incidence of different polarized light. These conditions can provide theoretical bases for the subsequent design of high-efficiency beam deflection metasurfaces. The relationship between the highest achievable anomalous refraction efficiency and the number of nanoparticles within one period of the metasurface is also summarized. In addition, the generalized refraction should not depend on the polarization states of incident light; however, the previous realization conditions of anomalous refraction were sensitive to the polarization states. Thus, conditions for establishing the polarization-independent generalized Snell's law of refraction in all-dielectric metasurfaces are presented.
广义斯涅尔定律表明，在两种介质的界面处引入相位梯度可以塑造入射光并实现异常反射或折射。然而，当通过超表面中纳米颗粒的散射来实现引入的相位梯度时，该定律需要修正；该定律成立时需要满足一定条件。我们给出了在不同偏振光入射下，全介质超表面中建立“广义折射斯涅尔定律”的条件。这些条件可为后续高效光束偏转超表面的设计提供理论依据。还总结了超表面一个周期内可实现的最高异常折射效率与纳米颗粒数量之间的关系。此外，广义折射不应依赖于入射光的偏振态；然而，先前异常折射的实现条件对偏振态很敏感。因此，给出了在全介质超表面中建立与偏振无关的广义折射斯涅尔定律的条件。
