Flexible Terahertz Metasurface Supporting Bound State in the Continuum for Refractive Index Based Staphylococcus Aureus Sensing

作者：Zijie Dai, Can Yan, Ying Liang, Jitao Li, Xiaoxian Song, Jingjing Zhang, Zhen Yue, Zhang Zhang, Xinghua Zhu, Yunxia Ye, Xudong Ren · 发表于：IEEE Transactions on Terahertz Science and Technology · 年份：2025 · DOI：10.1109/tthz.2025.3587427 · 被引用次数：5 · 研究领域：Metamaterials and Metasurfaces Applications、Molecular Communication and Nanonetworks、Terahertz technology and applications

Staphylococcus aureus (S. aureus) represents a major threat to global health, and its sensitive and accurate detection is highly demanded in disease diagnosis and food safety. Here, a flexible terahertz (THz) metasurface based on bound states in the continuum (BIC) is proposed and experimentally demonstrated for the trace analysis of S. aureus. The unit cell structure incorporates a metallic square with two opening gaps, supporting a resonance transition from BIC to quasi-BIC states by introducing a symmetry perturbation to one opening gap location. Firstly, the refractive index (RI) spectra of the drip-dried S. aureus solution at different concentrations are characterized using THz-TDS. The frequency point possessing a maximum linearity between RI and S. aureus concentrations is selected as the resonance frequency of designed sensing quasi-BIC. Moreover, an experimental demonstration of the sensing performance is conducted by monitoring spectral evolution after target loading. The measured results indicate that the constructed biosensor exhibits a detection limit down to 200 cfu/mL and RI sensing sensitivity up to 267.1 GHz/RIU for S. aureus measurement. Hence, the flexible, easy manufacturing, and highly-sensitive quasi-BIC metasurface biosensor paves a new way toward developing novel bacteria sensors and BICs-related optoelectronic devices.