Directional Janus Metasurface

作者：Ke Chen, Guowen Ding, Guangwei Hu, Zhongwei Jin, Junming Zhao, Yijun Feng, Tian Jiang, Andrea Alù, Cheng‐Wei Qiu · 发表于：Advanced Materials · 年份：2019 · DOI：10.1002/adma.201906352 · 被引用次数：320 · 研究领域：Metamaterials and Metasurfaces Applications、Advanced Antenna and Metasurface Technologies、Plasmonic and Surface Plasmon Research

Janus monolayers, a class of two-faced 2D materials, have received significant attention in electronics, due to their unusual conduction properties stemming from their inherent out-of-plane asymmetry. Their photonic counterparts recently allowed for the control of hydrogenation/dehydrogenation processes, yielding drastically different responses for opposite light excitation spins. A passive Janus metasurface composed of cascaded subwavelength anisotropic impedance sheets is demonstrated. By introducing a rotational twist in their geometry, asymmetric transmission with the desired phase function is realized. Their broken out-of-plane symmetry realizes different functions for opposite propagation directions, enabling direction-dependent versatile functionalities. A series of passive Janus metasurfaces that enable functionalities including one-way anomalous refraction, one-way focusing, asymmetric focusing, and direction-controlled holograms are experimentally demonstrated.