Wide spectrum multiple Fano resonances for high sensitivity detection of refractive index and temperature in MIM waveguides coupled with racetrack resonator nanorod-arrays

Abstract In this paper, we designed a metal-insulator-metal (MIM) waveguides based plasmonic sensor coupled with a racetrack cavity adorned with zero Dimensional (0D) nanorod-arrays exhibiting high sensitivity detection of refractive index variations measured as spectral shifts in the resonance wavelengths. The finite-difference time-domain method (FDTD) was used to simulate and study the optical platform based on MIM waveguide and nanorod-array racetrack resonator as a detection refractive index (RI) sensor and for temperature and Diabetes sensing, with sensitivity as high as 4250 nm per RIU and 0.42 nm/°C and 3204 nm/RIU, respectively. The nanorod arrays on the racetrack resonator enhance the light-matter interaction. Which increased the sensitivity. We evaluated the impacts of radius and refractive index on the racetrack resonator's sensitivity using the spectra shifts as sensor performance. As a result, the proposed plasmonic structures exhibit strong potential for a variety of sensor applications for offering high-sensitivity detection of low concentrations of small molecules similar to glucose and temperature.