Large-area gate-tunable terahertz plasmonic metasurfaces employing graphene based structures

We design and experimentally investigate various large-area gate-tunable terahertz plasmonic metasurfaces employing different types of graphene based structures, i.e. arrays of graphene ribbons, square-lattice graphene anti-dots and hexagonal-lattice graphene anti-dots. Distinct gate-tunable resonances in the terahertz frequency range arising from excitations of plasmonic resonance modes associated with different structures are observed in their transmission spectra. Carrier density dependent tuning of the resonance frequency exhibits excellent agreement with the theoretical prediction and the numerical simulation. The demonstrated graphene based terahertz plasmonic metasurfaces can be employed to realize more complex devices and functionalities such as tunable plasmonic waveguide and transformation optics.