Dynamically Tunable Plasmon-Induced Transparency Based on an H-Shaped Graphene Resonator

We propose a dynamically adjustable plasmon-induced transparent (PIT) plane device consisting of a periodic H-shaped graphene resonator (HSGR). For the symmetrical pattern, only dipole resonance is observed at a normal incidence excited with electric field along the x-direction. Once the asymmetry is introduced into the structure, the magnetic dipole mode that is not accessible in the symmetric structure can be excited, and the interference between the continuum and the leaky modes in HSGR forms a PIT window in original dipole resonance absorption band. The spectrum responses of HSGR can be flexibly regulated by transforming geometric parameters of U-shaped cavity as well as the Fermi energy of graphene. Besides, an optical delay time more than 0.04 ps and a figure-of-merit value 17.78 are obtained in our design structure. Our studies may open up avenues for fabricating compact equipment in appealing bio-chemical sensors and slow-light devices.