Refractive index sensing with optical bound states in the continuum

TL;DR

This paper presents a novel approach to refractive index sensing using optical bound states in the continuum (BICs) in dielectric gratings, including analytical formulas, optimization strategies, and numerical validation.

Contribution

It introduces a perturbative method to evaluate sensor sensitivity near BICs and provides an optimization framework for designing highly effective optical sensors.

Findings

Derived differential sensitivity and figure of merit for BIC-based sensors

Provided an analytic formula for maximal sensitivity with optical BICs

Validated results with numerical simulations

Abstract

We consider refractive index sensing with optical bounds states in the continuum (BICs) in dielectric gratings. Applying a perturbative approach we derived the differential sensitivity and the figure of merit of a sensor operating in the spectral vicinity of a BIC. Optimisation design approach for engineering an effective sensor is proposed. An analytic formula for the maximal sensitivity with an optical BIC is derived. The results are supplied with straightforward numerical simulations.