Huygens’ metasurface: From anomalous refraction to reflection

Huygens' metasurfaces (HMS) without any reflection or transmission are widely studied due to the high-efficiency manipulation of electromagnetic waves. In this work, three-layered metallic Huygens' metasurfaces are proposed and the geometry-dependences of anomalous refraction and reflection are investigated. The surface impedance and admittance are independently tailored by changing the length of metallic resonators, which is dictated by the introduction of the intermediate layer. Huygens' metasurfaces can be geometrically engineered to realize anomalous refraction with an efficiency of 62% and anomalous reflection with an efficiency of 60%, respectively. It is anticipated that the proposed metasurface with tunable materials could achieve reconfigurable terahertz devices.