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ORIGINAL RESEARCH article

Front. Phys.

Sec. Optics and Photonics

Volume 13 - 2025 | doi: 10.3389/fphy.2025.1572555

This article is part of the Research Topic Frontiers in Metamaterials: Advances in Electromagnetic Devices and Systems View all articles

Chiral Permittivity-Asymmetric Metasurfaces Empowered by Bound States in the Continuum

Provisionally accepted
  • Hunan University, Changsha, China

The final, formatted version of the article will be published soon.

    The intrinsic chirality of natural materials is usually weak or absent. To enlarge circular dichroism, chiral metasurfaces supporting bound states in the continuum have been widely investigated. These chiral metasurfaces have demonstrated considerable potential to achieve high quality (Q) factors but require ultra-small structure asymmetry and complicated fabrication processes. Here we propose a novel approach to break the in-plane symmetry of the structure by introducing refractive index perturbations. Furthermore, we demonstrate the efficient intrinsic chiral emission from resonant metasurfaces which are composed of two slant titanium dioxide (TiO2) bars arranged on a square lattice. Numerical calculations indicate that the intrinsic chirality of our metasurfaces at normal incidence achieves near-unity circular dichroism of 0.99 and an ultra-high Q factor exceeding 𝟏𝟎^𝟔 . The relationship between the two perturbations and CD and Q factor has also been studied, offering the flexibility to enhance and tailor chirality and Q factor simultaneously. Our chiral metasurfaces may lead to applications in chiral lasers, chiral light detectors, chiral biosensing, and chiral nonlinear filters.

    Keywords: metasurface, Chirality, Circular Dichroism, BiCS, High-efficiency

    Received: 07 Feb 2025; Accepted: 05 Mar 2025.

    Copyright: © 2025 Li, Mao, Yin, Zhou, Sun and Tang. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Zhixiang Tang, Hunan University, Changsha, China

    Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.

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