Plasmonic Fano-like resonance in double-stacked graphene nanostrip arrays

We studied the plasmonic response in graphene nanostructures consisting of double-stacked graphene nanostrip arrays with a dielectric spacer on a substrate. The finite-difference time-domain simulations show that the Fano-like resonance in the mid-IR region can be generated due to the plasmonic coupling between the upper- and lower-layer graphene nanostrips. The resonance spectrum can also be effectively controlled by adjusting the geometrical parameters of the graphene system, such as the central position of the graphene nanostrips and the coupling distance between the upper- and lower-layer graphene nanostrips. Moreover, it was found that Fano-like resonance relies on the Fermi level of graphene and polarization angle of incident light, and the spectral response can be well analyzed by using the coupled-mode theory. These results would offer a new pathway to manipulate mid-IR light at the nanoscale and realize ultrasmall graphene functional devices.