Research on sensing characteristics of high Q-factor all-dielectric metasurfaces based on geometric breaking

• Published in: Optics communications 2025-01, Vol.574, p.131122, Article 131122
• Main Authors: Chen, Ying, Zhao, Guoting, Wang, Zhongyao, Shi, Moqing, Zhu, Qiguang
• Format: Article
• Language: English
• Subjects: All-dielectric metasurfaces; Bound states in the continuum (BIC); Breaking of geometric symmetry; Group theory; Q-factor
• ISSN: 0030-4018
• DOI: 10.1016/j.optcom.2024.131122

The bound states in the continuum (BIC) are widely used in designing metamaterials with high quality factor (Q-factor) resonances due to their perfect localization in the continuous spectral range coexisting with expanding waves. In this study, a T-shaped nanohole all-dielectric metasurface structure is proposed based on the unique electromagnetic properties of all-dielectric metasurfaces, and the fundamental reason of its coupled state and the theoretical basis of BIC excitation are deeply investigated based on the theory of group theory, and the geometric symmetry is broken from multiple angles, and the coupling relationship between discrete eigenmodes and the external continuum is specifically analyzed during the change of symmetry, its spectral response and near-field distribution are numerically calculated. In addition, based on the modulation mechanism of the incident light polarization angle, the three-channel resonance tuning with two resonances of the same frequency and one of a different frequency is realized under the condition that the resonance position and the Q-factor are not affected. This study not only provides a theoretical basis for the excitation conditions and evolution regularity of symmetry-protected BIC, but also solves the problem in the traditional analysis of resonance phenomena without taking the high Q-factor and stability into account, which can provide new designing methods for optical metasurface devices with multi-channel resonance. •The fundamental reason of its coupled state and the theoretical basis of BIC excitation are deeply investigated based on the theory of group theory.•The geometric symmetry is broken from multiple angles, and the coupling relationship between discrete eigenmodes and the external continuum is specifically analyzed during the change of symmetry.•Based on the modulation mechanism of the incident light polarization angle, the three-channel resonance is realized under the condition that the resonance position and the Q-factor are not affected.