Plasmonic resonance of distorted graphene nano-ribbon analyzed by boundary element method

Surface plasmon resonances (SPRs) of graphene nano-ribbons (GNRs) have great application potentials in sensing, wave-front control and wave absorbing. However, as a flexible material, graphene is often observed with corrugations in the fabrication and transfer processes. Here the scattering properties of a distorted GNR with a bending ridge are studied by the boundary element method (BEM). It is found that, compared with the flat GNRs, the resonant wavelengths are red-shifted, and the resonant intensity of the 1st order mode is decreased, while that of the higher order modes are increased dramatically for the distorted GNRs. Particularly, due to the appearance of the ridge, both odd modes and even modes are able to be stimulated under tilted incidence. In addition, as the ridge increases, the resonances corresponding to various order modes change in different ways. Applying the spring oscillator theoretical model, these results are explained by the blocking effect of the ridge on the motions of electrons. This work is anticipated to help to understand the physical mechanisms of plasmonic resonances of curved GNRs and distorted structures.