Sensitive refractive index sensing with good operation angle polarization tolerance using a plasmonic split-ring resonator array with broken symmetry

Abstract

A localized plasmon resonance sensor consisting of an asymmetric split-ring resonator array sustaining highly localized field energy with high refractive index sensitivity and good figure of merit is demonstrated and investigated. In the proposed 3-cut split-ring resonator structure with broken symmetry, a highly tunable transmission with a large modulation depth and a narrow resonance linewidth is obtained, which shows polarization-insensitive and angle-independent properties. Numerical calculation results show that a high sensitivity of up to 1006 nm/RIU and a figure of merit of 9.7 can be reached. This plasmonic index sensor is practically obtainable, and is expected to have potential applications for high-sensitivity convenient and efficient detection.