Highly sensitive plasmonic sensor with a coupled split-square-ring resonator

Abstract A novel plasmonic sensor, which is composed of a metal-insulator-metal (MIM) waveguide and a coupled split-square-ring resonator, is proposed and investigated by utilizing the two-dimensional (2D) finite-difference time-domain (FDTD) method. The optimized results demonstrate that the proposed sensor is highly sensitive to variations of refractive index (RI) and temperature, i.e. the RI and temperature sensitivities are up to 2040 nm RIU −1 and −1.2 nm/°C, respectively. Numerical simulations reveal that the sensing performance can still be further improved via optimization of the structure. This research may open up new schemes in realizing high-sensitive biosensors with compact configurations.