Sensitivity enhancement of the LSPR-based tapered optical fiber biosensor by variation of nanoparticle arrangement

A tapered optical fiber sensor with four arrangements of gold nanoparticles (Au NPs) on its waist is simulated and the fiber transmittance by changing the analyte refractive index (RI) is obtained. The method is a combination of the finite-difference time-domain method and the finite element method. The effect of NPs on top of each other and dimers is investigated, which is the first step in studying the aggregation of NPs in the cluster NP model. In addition, the effects of fiber diameter, NP diameter, and fiber length are examined. It is shown that by variation of NP arrangement, the amplitude sensitivity increases from 1.5 per refractive index unit (RIU-1) to 4.53 RIU-1 and the wavelength sensitivity increases from 58.24 to 116.74 nm/RIU. The dimensions of the structures and the ranges of analyte RIs are in the field of practical biosensors, to be close to reality and to be effective in diagnosing diseases. (c) 2023 Optica Publishing Group

Automated summary

In this study, a tapered optical fiber sensor with gold nanoparticles is simulated and the effect of nanoparticle arrangement on the sensor's sensitivity is investigated. The results show that by varying the arrangement, the sensor's amplitude sensitivity and wavelength sensitivity can be increased, making it practical for applications in biosensing.