Tunable plasmon induced transparency based on bright-bright mode coupling graphene metamaterial

A graphene-based metamaterial structure with tunable plasmon induced transparency (PIT) effect is numerically and theoretically researched in this paper. Both the collinear and parallel graphene strips serve as bright mode and a PIT window emerges due to the weak hybridization between them. The transparency window can be tuned by not only adjusting the geometry parameter of the structure but also changing the chemical potential of the graphene strips. Different from the reported tunable PIT system, the spectra width and resonance strength can be tuned with the PIT peak at a fixed frequency in this research. Moreover, the Q factor can be affected by the distance between two bright modes and a figure of merit (FOM) as high as 15.20 can be achieved in this research. These properties expand the application for PIT phenomenon in mid-infrared metamaterial devices, such as filter, modulator and sensor.