Reconfigurable terahertz plasmonics and metamaterials using graphene

We discuss recent work on graphene-based reconfigurable terahertz metamaterials. In particular two approaches towards constructing reconfigurable metamaterials are analyzed and compared, namely: (i) graphene only plasmonic structures, and (ii) graphene-metal hybrid metamaterials. Whereas in the first type of structures graphene has two simultaneous roles: (a) as a plasmonic medium, therefore defining the terahertz structural response of the metamaterial, and (b) as a reconfigurable medium, thus inducing changes in the metamaterial terahertz response, in the second type of structures the terahertz response is set primarily by the metallic pattern and graphene has just the role of constituting a reconfigurable medium. It is observed that whereas relaxation time is the most important parameter affecting the quality of the terahertz response in plasmonic metamaterials, for the analyzed graphene-metal hybrid metamaterial geometries, the conductivity swing in graphene is the main parameter affecting the terahertz response of the device.