Enhanced sensitivity of an all-dielectric refractive index sensor with optical bound state in the continuum

TL;DR

This paper develops an analytic model for the sensitivity of an all-dielectric refractive index sensor based on optical bound states in the continuum, and proposes design optimization to maximize sensitivity.

Contribution

It introduces an analytic expression for bulk sensitivity using Zel'dovich perturbation theory and offers a design optimization strategy for enhanced sensor performance.

Findings

Derived an analytic sensitivity expression for dielectric sensors

Identified the upper sensitivity limit for the sensor

Validated results with numerical simulations

Abstract

The sensitivity of a refractive index sensor based on an optical bound state in the continuum is considered. Applying Zel'dovich perturbation theory we derived an analytic expression for bulk sensitivity of an all-dielectic sensor utilizing symmetry protected in-$\Gamma$ optical bound states in a dielectric grating. The upper sensitivity limit is obtained. A recipe is proposed for obtaining the upper sensitivity limit by optimizing the design of the grating. The results are confirmed through direct numerical simulations.