Numerical modelling of light propagation in surface plasmon resonance sensor with liquid crystal

TL;DR

This paper presents a theoretical model of a five-layer nanorod surface plasmon resonance sensor with an inhomogeneous liquid crystal layer, demonstrating how voltage and prism index influence sensitivity and reflectance for detecting analyte refractive index.

Contribution

It introduces a novel theoretical approach to control and optimize light propagation in a plasmonic sensor using liquid crystal director reorientation.

Findings

Reflectance depends on incident angle and applied voltage.

Director reorientation shifts the position of reflective dips.

Sensor sensitivity can be tuned by adjusting voltage and prism index.

Abstract

The five-layer nanorod-mediated surface plasmon sensor with inhomogeneous liquid crystal layer was theoretically investigated. The reflectance as the function of the incident angle was calculated at different voltages applied to the liquid crystal (LC) for different analyte refractive indices. By changing the LC director orientation one can control the position of the reflective dips and choose the one that is the most sensitive to the analyte refractive index. At the chosen angle of incidence, the analyte refractive index can be found from the reflectance value. The director reorientation effect is stronger when the prism refractive index is between ordinary and extraordinary refractive indices of the LC. In this case, the voltage increase and the prism refractive index decrease have a similar effect on the reflectance features.