Tunable multimode plasmon-induced transparency with graphene side-coupled resonators

We investigate a plasmonic graphene waveguide system based on monolayer graphene and two side-coupled graphene rings. The system exhibits multimode plasmon-induced transparency (PIT) effects in the mid-IR region. The dark-bright coupling mechanisms and coupled-resonator-induced transparency (CRIT) theory are both utilized to explain the electromagnetic responses, and the explanation is verified by simulation results of the finite-element method (FEM). By varying the Fermi level of graphene or the coupling gap, we have a means to dynamically manipulate the PIT system.