A Nanoscale Structure Based on a Ring With Matchstick-Shape Cavity for Glucose Concentration and Temperature Detection

The design of micro-nano optical structure is the key problem in the improvement of integrated optical device. In this work, a compact nanosensor structure comprising metal-insulator-metal (MIM) waveguide and a ring with a matchstick-shape cavity (RMSC), is proposed and numerically simulated by using the finite element method. The transmission characteristics of this nanosensor structure are systematically analyzed. Moreover, the influences of the position of matchstick-shape structure inside the ring and the various structural parameters of RMSC on Fano resonance are discussed. The sensitivity and figure of merit (FOM) are used to describe the sensing performance. The maximum sensitivity can achieve 2162 nm/RIU with a FOM of 52.73. Furthermore, the applications of designed structure are investigated, which include biological detection and temperature sensing. The temperature sensitivity reaches as high as 1.525 nm/°C, and the best sensitivity of biosensor for detecting glucose concentration is 0.45 (nm \cdot L)/g. The results pave a promising route toward ultra-compact plasmonic sensors for achieving high sensitivity and smaller scales, and applying in optical on-chip nanodevice in the future.