Anderson localization of surface plasmons in monolayer graphene

Graphene is a two-dimensional material that has been highly regarded with its unique features to excite surface plasmonic waves. In this paper, we present the Anderson localization of surface plasmons in monolayer graphene. Here we proposed an active plasmonic device that consists of a monolayer graphene on silicon random grating to trap the surface plasmons in local cavities that are created by random multiple scattering. The quality factor of localized graphene surface plasmons (GSPs) is greater than the corresponding factor for uniformly distributed GSPs in periodic silicon substrate (reported before) up to three times. The field intensity of spatially localized GSPs in monolayer graphene is increased by a factor of 15 compared to GSPs in periodic grating. Our simulation results also show that the bandwidth of excitation spectrum of GSPs is extended as a result of introducing randomness in period in order to realize the desired random grating structure. Although the tuning of resonance frequencies of Anderson localized GSPs is a challenging task due to its random nature, here we tune the resonance frequencies of localized surface plasmons by using an external gate voltage for adjusting the Fermi level of monolayer graphene.