Dynamically Tunable Electromagnetically Induced Transparency in Graphene and Split-Ring Hybrid Metamaterial

Abstract

In this letter, a novel hybrid metamaterial consisting of periodic array of graphene nano-patch and gold split-ring resonator has been theoretically proposed to realize an active control of the electromagnetically induced transparency analog in the mid-infrared regime. A narrow transparency window occurs over a wide absorption band due to the coupling of the high-quality factor mode provided by graphene dipolar resonance and the low-quality factor mode of split-ring resonator magnetic resonance, which is interpreted in terms of the phase change and surface charge distribution. In addition to the obvious dependence of the spectral feature on the geometric parameters of the elements and the surrounding environmental dielectric constant, our proposed metamaterial shows great tunabilities to the transparency window by tuning the Fermi energy of the graphene nano-patch through electric gating and its electronic mobility without changing the geometric parameters. Furthermore, our proposed metamaterial combines low losses with very large group index associated with the resonance response in the transparency window, showing it suitable for slow light applications and nanophotonic devices for light filter and biosensing.