Ultrasensitive Biosensing by Radiative Q factor Modulation in Strongly Coupled 3D BIC Metasurfaces

This repository contains the custom MATLAB code used for the analytical calculations of the Q-modulated refractometric sensing mechanism presented in the manuscript Ultrasensitive Biosensing by Radiative Q-factor Modulation in Strongly Coupled 3D BIC Metasurfaces. Specifically, the code computes the refractive-index-dependent evolution of the radiative quality factor (Qr), total quality factor (Q), resonance linewidth, absorption, and relative intensity variation (ΔI) in the strongly coupled system. It was used to generate the theoretical results shown in Fig. 1d, including the comparison of systems with different initial radiative quality factors (Qr0→∞ and Qr0=10^3). The code also saves all calculated results in a MATLAB .mat file for further analysis and plotting. Detailed derivations of the analytical model are provided in Supplementary Note S1 of the manuscript.