Dynamically Tunable Terahertz Plasmon-Induced Transparency Analogy Based on Asymmetric Graphene Resonator Arrays

A plasmon-induced transparency (PIT) effect based on an asymmetric graphene loop structure has been proposed and investigated in this paper. The microstructure consists of a pair of graphene square loops and a dielectric substrate. The calculated results show that the transparency peak can be produced at 5.68 THz by the frequency detuning between two different graphene square loops. The geometric parameters of microstructure, such as the coincidence degree between two square loops, the length and the width of two square loops, will affect the position of PIT-window. Moreover, by adjusting the Fermi level of graphene through external gate voltage, the PIT-window can be dynamically tuned. Importantly, the PIT-window in graphene metamaterials can also serve as the amplitude modulator at the fixed frequency and the refractive index sensor. In addition, an improved microstructure is proposed for realizing the multi-PIT-window. The amplitude modulation of multi-PIT-window can be adjusted up to 53% by controlling the coupling distance, which has certain application prospects in the fields of double-channel filters, optical switches, and modulators.