Graphene-based tunable terahertz electromagnetically induced transparency using metamaterial structure

A graphene-based tunable electromagnetically induced transparency (EIT)-like metamaterial structure operating at the terahertz regime is proposed and numerically analyzed. The unit cell of the metamaterial structure consists of a split-ring resonator and twofolded-line pair resonators, performing as the quasi-dark mode and bright mode, respectively. When the incident waves vertically illuminate upon the metamaterial structure, a transmission peak can be observed. Moreover, the frequency of the transparency window can be flexibly adjusted by changing the Fermi energy level of graphene. A classical coupled two-oscillator model is employed to theoretically analyze the physical mechanism of EIT-like phenomenon, which is due to the near-field coupling effect between the bright and the quasi-dark modes. The proposed work will be a good candidate for the design of different graphene-based tunable EIT devices at different frequency spectra with potential applications in optical sensors.