Theoretical realization of dynamically tunable double plasmonically induced transparency in a graphene-based waveguide structure

A graphene-based waveguide coupled with radiative and subradiant graphene ribbon resonators is proposed to represent the four-level energy diagram in conventional atomic systems and demonstrate a new realization of dynamically tunable double plasmonically induced transparency (DPIT). The radiative resonator is achieved with the help of direct coupling from the graphene waveguide while indirect coupling is relied for the subradiant resonator. By combining the numerical simulation results and the dressed theory, the physical mechanism behind the DPIT is presented in detail. The DPIT phenomenon is derived from the mode splitting caused by the phase-coupled effects. By controlling the Fermi energy level of graphene ribbon, the double transparency windows can be dynamically tuned. The proposed structure may find its application in optical communication or other novel terahertz integrated optical circuits and devices.