发表机构
Universidad de Málaga; CNRS, Université Paris-Saclay; Adelaide University; National Research Council Canada（马拉加大学; 法国国家科学研究中心，巴黎萨克雷大学; 阿德莱德大学; 加拿大国家研究委员会）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文提出基于不同布拉格光栅能带反转的拓扑光子腔新策略，突破对称约束，实验验证了无需周期偏移的硅腔拓扑模式。
AI 中文摘要
拓扑光子腔为鲁棒的光学限制和增强的光与物质相互作用提供了一条强大途径。在一维周期结构中具有不同拓扑相的边界处出现的界面态，使得超小模式体积和对无序的内在防护成为可能。现有实现通常通过在腔体两侧重新定义晶胞来创建平凡相和拓扑相，从而使两个周期结构共享相同的能带结构。这一约束限制了设计灵活性和可实现的器件范围。在此，我们提出了一种根本不同的策略，即通过组合具有不同能带结构的周期波导来实现拓扑腔。通过利用布拉格光栅中的带隙闭合和能带反转，我们独立控制每个结构的拓扑相和带隙宽度。我们实验实现了由两种不同布拉格光栅构成的硅拓扑腔，无需周期偏移，并观察到尽管两个光栅存在显著差异，拓扑模式仍然存在。我们的结果确立了拓扑光子腔设计的新途径，证明不同布拉格光栅之间的能带反转能够在对称约束之外实现腔体形成，并提供了一种通过镜面不对称性来工程化光学限制的机制。
英文摘要
Topological photonic cavities offer a powerful route to robust optical confinement and enhanced light-matter interactions. Interface states that emerge at the boundary between one-dimensional periodic structures with distinct topological phases, enable cavities with ultra-small mode volumes and intrinsic protection against disorder. Existing implementations typically create the trivial and topological phases by redefining the unit cell on either side of the cavity, so that both periodic structures share the same band structure. This constraint limits design flexibility and the range of accessible devices. Here we introduce a fundamentally different strategy for realizing topological cavities based on combining periodic waveguides with distinct band structures. By exploiting bandgap closing and band inversion in Bragg gratings, we independently control the topological phase and bandgap width of each structure. We experimentally realize silicon topological cavities formed by two different Bragg gratings without period shifting, and observe topological modes despite significant differences between the two gratings. Our results establish a new route to topological photonic cavity design, demonstrating that band inversion between dissimilar Bragg gratings enables cavity formation beyond symmetric constraints and provides a mechanism to engineer optical confinement via mirror asymmetry.
