Dynamically Tunable Fano Resonance Based on Graphene Metamaterials

We introduce a remarkably simple coplanar nanostructure consisting of two longer and one shorter graphene nanorods to support a Fano resonance, which arises from the coupling between bright mode and dark mode by breaking the geometrical symmetry. Simulation results, performed with the finite-difference time-domain method, show that the resonant frequency of the bright mode in the transmission spectrum can be independently tuned by changing the lateral offset of the shorter graphene nanorod, while changing its longitudinal offset can independently adjust the resonant frequency of the dark mode. Furthermore, Fano resonance spectrum can also be regulated actively by altering the Fermi energy of graphene as well as refractive index of the surrounding media. This letter proposes a unique modulation strategy of Fano resonance in metamaterials, assisting in developing potential in applications of sensor devices and some other plasmonic functional devices.