Surface plasmon resonance and field confinement in graphene nanoribbons in a nanocavity

In this work, we demonstrate surface plasmon resonance properties and field confinement under a strong interaction between a waveguide and graphene nanoribbons (GNRs), obtained by coupling with a nanocavity. The optical transmission of a waveguide-cavity-graphene structure is investigated by finite-difference time-domain simulations and coupled-mode theory. The resonant frequency and intensity of the GNR resonant modes can be precisely controlled by tuning the Fermi energy and carrier mobility of the graphene, respectively. Moreover, the refractive index of the cavity core, the susceptibility chi((3)) and the intensity of incident light have little effect on the GNR resonant modes, but have good tunability to the cavity resonant mode. The cavity length also has good tunability to the resonant mode of cavity. A strong interaction between the GNR resonant modes and the cavity resonant mode appears at a cavity length of L-1 = 350 nm. We also demonstrate the slow-light effect of this waveguide-cavity-graphene structure and an optical bistability effect in the plasmonic cavity mode by changing the intensity of the incident light. This waveguide-cavity-graphene structure can potentially be utilised to enhance optical confinement in graphene nano-integrated circuits for optical processing applications.

Automated summary

This work demonstrates the surface plasmon resonance properties and field confinement between a waveguide and graphene nanoribbons under a strong interaction obtained by coupling with a nanocavity. The resonant frequency and intensity of the GNR resonant modes can be precisely controlled by tuning the Fermi energy and carrier mobility of the graphene, while the cavity length also has good tunability to the resonant mode of cavity. The optical transmission of a waveguide-cavity-graphene structure and the slow-light effect and optical bistability effect in the plasmonic cavity mode are investigated in this study.