Wang Xiangdong, Bongiovanni Domenico, Wang Ziteng, Abdrabou Amgad, Hu Zhichan, Jukić Dario, Song Daohong, Morandotti Roberto, El-Ganainy Ramy, Chen Zhigang, Buljan Hrvoje
TEDA Applied Physics Institute and School of Physics, Nankai University, Tianjin 300457, China.
INRS-EMT, 1650 Blvd. Lionel-Boulet, Varennes, Quebec J3X 1S2, Canada.
ACS Photonics. 2024 Jul 17;11(8):3213-3220. doi: 10.1021/acsphotonics.4c00600. eCollection 2024 Aug 21.
Topological bound states in the continuum (BICs) are localized topological boundary modes coexisting with a continuous spectrum of extended modes. They have been realized in systems with symmetry-protected topological phases, where their immunity to defects and perturbations depends on the presence of symmetries. Here we propose a method that transforms an in-gap topological boundary state into a BIC by using the concept of subsymmetry. We design the coupling between a system possessing in-gap topological modes and a system possessing a continuum of states that results in topological BICs. We define the criteria for the coupling that yields the desired results. To implement this scheme, we construct representative topological BICs based on one-dimensional Su-Schrieffer-Heeger models and implement them in photonic lattices. Our results not only reveal novel physical phenomena but may also provide methods for designing a new generation of topological devices.
连续统中的拓扑束缚态（BICs）是与扩展模式的连续谱共存的局域化拓扑边界模式。它们已在具有对称性保护拓扑相的系统中实现，在这些系统中，它们对缺陷和微扰的免疫性取决于对称性的存在。在此，我们提出一种方法，通过使用子对称性的概念将能隙中的拓扑边界态转变为BIC。我们设计了具有能隙拓扑模式的系统与具有连续态的系统之间的耦合，从而产生拓扑BIC。我们定义了产生期望结果的耦合标准。为了实现该方案，我们基于一维Su-Schrieffer-Heeger模型构建了具有代表性的拓扑BIC，并在光子晶格中实现了它们。我们的结果不仅揭示了新颖的物理现象，还可能为设计新一代拓扑器件提供方法。
