Multiple and tunable plasmon induced transparency with L-shape graphene strips structure at terahertz frequency

Abstract

Firstly, in this paper, the proposed structure is composed of a transverse graphene rectangular cavity and a vertical graphene rectangular cavity, so as to produce the plasmon-induced transparency (PIT) phenomenon. The PIT of graphene metamaterials is theoretically explored by using the finite-difference time-domain (FDTD) simulation and the coupled-mode-theoretical (CMT) analysis. Then, by adjusting the Fermi level of graphene, the PIT window is dynamically adjusted, so that the structure can be used as an optical switch. Furthermore, the refractive index sensitivity of the PIT window is investigated and the simulation results show that a sensitivity of 2.725 THz/RIU is achieved. In addition, multiple PIT windows are also generated by adding additional matched L-type graphene strips. Finally, the proposed structure may enlighten the developments of dynamically tuned terahertz devices.