Liu Weijie, Yan Wenchao, Cheng Weizhao, Zhang Bin, Wu Bo, Zhu Han, Chu Lingrui, Jia Yuechen, Chen Feng
Opt Lett. 2024 Oct 1;49(19):5587-5590. doi: 10.1364/OL.538623.
A topological bound state in the continuum (TBIC) is a novel topological phase that has attracted significant attention. Different from conventional topological insulators (TIs), where boundary states reside within gaps, TBICs can support unconventional boundary states that remain isolated from the surrounding bulk states. In this work, we experimentally demonstrate multiple TBICs in photonic bilayer trimer lattices using femtosecond laser writing technology. By modulating the interlayer coupling between two trimer chains, we observe the emergence of two distinct types of TBICs. Moreover, we experimentally achieve the coexistence of in-gap topological states and TBICs and demonstrate the transformation between them. Our work unveils new insights into the flexible construction of TBICs, and this method can be easily applied to other one-dimensional topological structures, offering promising avenues for further research.
连续统中的拓扑束缚态（TBIC）是一种新型拓扑相，已引起广泛关注。与传统拓扑绝缘体（TI）不同，传统拓扑绝缘体的边界态位于能隙内，而TBIC可以支持与周围体态隔离的非常规边界态。在这项工作中，我们使用飞秒激光写入技术在光子双层三聚体晶格中通过实验证明了多个TBIC。通过调制两个三聚体链之间的层间耦合，我们观察到两种不同类型的TBIC的出现。此外，我们通过实验实现了能隙内拓扑态和TBIC的共存，并证明了它们之间的转变。我们的工作揭示了关于TBIC灵活构建的新见解，并且这种方法可以很容易地应用于其他一维拓扑结构，为进一步研究提供了有前景的途径。
