Miniature resonator sensor based on a hybrid plasmonic nanoring

A miniature resonator sensor based on a hybrid plasmonic nanoring with a gold layer coated uniformly on the outer boundary is described and investigated. By using the Lumerical finite-difference-time-domain (FDTD) method, the optimized sizes of the plasmonic layer thickness and the central hole are given and insight into the dependence of spectral displacements, Q factors, sensitivity and detection limits on the ambient refractive index is presented. Simulation results reveal that the miniature resonator sensor featuring high sensitivity of 339.8 nm/RIU can be realized. The highest Q factor can reach similar to 60,000 with this nanoring and the minimum detection limit is as low as 1.5 x 10(-4) RIU. The effects on the resonance shifts and Q factors due to geometric shapes of the inner boundary of the nanoring are discussed as well. This miniature resonator sensor has good potential for highly sensitive ultracompact sensing applications. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement