Gated Graphene Enabled Tunable Charge-Current Configurations in Hybrid Plasmonic Metamaterials

An active hybrid toroidal metasurface is demonstrated based on artificially engineered plasmonic metamolecules deposited on a gate-controlled graphene layer. Our numerical predictions are confirmed by room-temperature time-domain spectroscopy characterizations in the terahertz frequency range. We quantitatively and qualitatively show that the gate-controlled active graphene metamaterial allows for an active tuning of the dynamic nonradiating toroidal dipole by tuning the essential mismatch in the spinning magnetic fields in the strongly coupled resonators. It is demonstrated that this feature can be obtained by varying the resistivity of gate-controlled graphene and tuning the capacitive coupling at the critical openings of the system.