Dynamically adjustable plasmon-induced transparency and switching application based on bilayer graphene metamaterials

A bilayer metamaterial composed of double graphene strips and square-ring graphene is proposed to realize plasmon induced transparency (PIT). The couple mode theory (CMT) is employed to explain the phenomenon of PIT, whose results are in good agreement with the simulation of the ?nite-difference time-domain. The dynamically adjustable PIT is investigated, where an on-to-off modulation composed of synchronous and asynchronous switching is realized by modulating the Fermi levels of graphene, the modulation degrees of amplitude are 67.5%, 86.1%, and 65.3%, respectively. The changes of transmission spectra are also studied by adjusting the coupling distance between double graphene strips and square-ring graphene, and the result shows that PIT is gradually disappeared with the increase of coupling distance and the decrease of coupling strength. Then, the corresponding relationships between dips of PIT and modes of CMT are described clearly, which are affected by the relative location between resonant points of the bright and dark modes.