Robust and high-performance plasmonic refractive index sensor based on graphene waveguide ring resonator

In this paper, we presented a robust and high performance plasmonic refractive index (RI) sensor based on graphene plasmon waveguide coupled to graphene nano-ring resonator. We analytically derived characteristics of the RI sensor such as resonance wavelength, wavelength sensitivity and figure of merit (FoM). And we showed a possibility of a high FoM by the structural symmetry of the resonator and a close relation between structural parameters, performance of the sensor and tunable physical properties of graphene. Based on the theoretical study, we suggested that one can achieve a high-performance of the sensor, regardless of a resonant mode selection and surrounding medium change, and can also compensate the fabrication defect of the sensor by adjusting chemical potential of the graphene ring resonator and waveguide. Numerical solution confirms the robust and high performance of the RI sensor, which would be a good candidate to develop practical nanoscale integrated sensors.