Simulation of LSPR Sensor Based on Exposed-Core Grapefruit Fiber With a Silver Nanoshell

A localized surface plasmon resonance (LSPR) sensor based on exposed-core grapefruit fiber (EC-GF) with a silver nanoshell (SNS) is presented. The SNS, composed of a dielectric core coated with a thin silver layer, is placed at the exposed section of the EC-GF as the sensing channel to avoid the metal coating, and then deposited with the analyte to avert the liquid filling. Two orthogonal polarized resonance peaks (x-polarized and y-polarized) can be observed due to the birefringence and each polarization exhibits multipolar plasmon resonances, which can realize the cross reference. Due to the good features of the SNS, the position of the LSPR band can be tuned in a broad range, from 2100 to 4020 nm, making the proposed sensor of great importance for biosensing. An extremely high sensitivity 7903.03 nm/RIU is obtained in the sensing range of 1.33-1.42, almost twice as high as the same type works. The influence of the SNS structure on the sensor's performance is also investigated numerically.