Accurate determination of the quality factor and tunneling distance of axisymmetric resonators for biosensing applications

TL;DR

This paper presents an improved finite element model for accurately determining the quality factor and tunneling distance of axisymmetric resonators, enhancing biosensing sensitivity through optimized microcavity geometries.

Contribution

An improved finite element model that accurately and efficiently determines the quality factor and tunneling distance of axisymmetric resonators for biosensing.

Findings

Model provides fast, accurate quality factor estimation.

Model validated numerically, analytically, and experimentally.

Optimized geometries improve biosensing sensitivity.

Abstract

Due to ultra high quality factor ($10^6-10^9$), axisymmetric optical microcavities are popular platforms for biosensing applications. It has been recently demonstrated that a microcavity biosensor can track a biodetection event as a function of its quality factor by using phase shift cavity ring down spectroscopy (PS-CRDS). However, to achieve maximum sensitivity, it is necessary to optimize the microcavity parameters for a given sensing application. Here, we introduce an improved finite element model which allows us to determine the optimized geometry for the PS-CRDS sensor. The improved model not only provides fast and accurate determination of quality factors but also determines the tunneling distance of axisymmetric resonators. The improved model is validated numerically, analytically, and experimentally.