Tunable electromagnetically induced transparency based on terahertz graphene metamaterial

Abstract

By patterning graphene on a SiO₂/Si substrate, in this paper, we designed and numerically investigated a terahertz electromagnetically induced transparency (EIT) graphene metamaterial, which consists of two coupled split ring resonators (SRRs) placed in an orthogonally twisted fashion, acting as the bright and dark elements, respectively. The calculated surface currents show that the dark mode excited by the near field coupling between two resonators can induce a distinct transparency peak in the transmission spectrum. Moreover, the amplitude and position of the transparency peak as well as the corresponding group delay can be actively tuned by changing the relaxation time or Fermi energy of graphene. Therefore, the graphene metamaterial with the actively tunable EIT peak exhibits potential applications in light storage, modulators, tunable sensors and switchers.