Pulley-type metallic microring surface plasmon polariton sensor based on Otto-configuration

In this study, we design a compact sensor with high sensitivity for refractive index change. A pulley-type metallic microring to produce surface plasmon polariton is proposed. The light is coupled onto the metallic microring using a dielectric waveguide. The 2-D finite-difference time-domain method is used to determine the optimal radius of the metallic microring. We also investigate the relation between the radius of the metallic microring and the sensitivity of the refractive index change. The highest sensitivity of 602.69 nm/RIU can be obtained at the resonance wavelength of 1536.7 nm.