Dielectric-Like Behavior of Graphene in Au Plasmon Resonator

Graphene has proven to be a promising conductive layer in fabricating optical plasmon resonators on insulator substrate using electron beam lithography and has the potential to construct electrically controlled active plasmon resonators. In this study, we investigate the effect of graphene on plasmon resonance using graphene and Au plasmon resonator system as a model at visible and near-infrared wavelength. Our experiment data show that the presence of graphene does not weaken and annihilate the plasmon resonance peaks, instead it predominantly makes the peaks redshift, which is similar to the behavior of depositing SiO₂ film on Au plasmon resonators. This fact indicates that graphene predominantly exhibits dielectric-like behavior at visible and near-infrared wavelength, which can be attributed to the low carrier density in graphene compared with metals.