Tunable metamaterials based on split ring resonators and doped graphene

We investigate electrically tunable split ring resonators (SRRs) obtained by coupling the SRRs with graphene in terahertz and near-infrared frequency range. Two different geometries are considered: SRRs on homogeneous graphene and SRRs with graphene patches inserted only in SRRs' gap. Graphene conductivity is tuned by changing its Fermi level. This gives tunable absorption in the graphene, which is strongly enhanced by large electric field in the vicinity of SRR resonances. As a result, SRR-graphene systems could be used as deeply subwavelength modulators with amplitude and phase tuning of the reflected field.