Transformation of Equivalent Graphene Plasmonics for Metagratings and Hyperbolic Metamaterials

Recent advances in graphene plasmonics offer numerous opportunities for enabling the design and manufacture of a variety of nanoscale optical devices. Here, a method of designing metagratings and hyperbolic metamaterials based on the geometrical transformation of the proposed equivalent graphene is reported. The physical mechanism underlying this method is the strongly enhanced light–matter interaction of equivalent graphene plasmonics, which can be characterized by effective conductance and remains constant in geometrical transformation. As proof of the method, we design and demonstrate a compact retroreflector that can anomalously reflect the incident wave along its original path utilizing the roll-up plasmonic structure. In addition, an air-medium hyperbolic metamaterial and hyperlens consisting of periodic plasmonic structures are also theoretically predicted and experimentally validated by anomalous diffraction. Compared with the existing approaches of designing these metadevices, the proposed method significantly lowers the requirement on their compositional materials. The concept of equivalent graphene effectively links optical and microwave plasmonics on the basis of the effective conductance model. In this case, the methodology of geometrical transformation can function in both the microwave and nanofields and serves as a platform for designing nanoscale and microwave focusing lenses and diverse on-chip optical wave control devices.