Refractive index sensor mim based waveguide coupled with a slotted side resonator

Abstract

In this paper, a plasmonic sensor based on a metal-insulator-metal (MIM) waveguide with a slotted side-coupled racetrack cavity is proposed. The transmission characteristics of the cavity are analyzed theoretically, and the improvements of performance for the racetrack cavity structure compared to a single disk cavity are studied. The influence of structural parameters on the transmission spectra and sensing performances is investigated thoroughly. The achieved sensitivity for the first mode was S = 959 nm/RIU and S = 2380 nm/RIU for the second one. Its corresponding sensing resolution is 1.04 × 10−5 RIU for mode 1 and 4.20 × 10−6 RIU for mode 2, respectively, and high transmissions are achieved at the two resonant wavelengths of 898.8 nm and 1857.1 nm. The proposed plasmonic sensor is a good candidate for designing novel devices and applications, in the field of chemical and biological sensing, and also in the field of plasmonic filters, switches, etc.