标题： 通过双零指数介质的拓扑态自由扩展 显示英文标题

标题： Free Extension of Topological States via Double-zero-index Media

摘要： 拓扑态因其对无序的鲁棒性而闻名，为抗无序器件提供了有前景的途径。 然而，它们在界面处的固有空间限制施加了几何约束，限制了拓扑功能的可扩展性。 在此，我们提出了一种策略，通过使用双零折射率介质来扩展拓扑界面，以克服这一限制。 尽管占据有限空间，这些介质在光学上等效于无限小的点，有效地改变了拓扑界面的几何结构，并打破了传统的体-边对应关系。 这种策略使得均匀拓扑态的空间扩展超出其原始界面，为拓扑光子器件提供了新的可能性。 我们通过二维光子Su-Schrieffer-Heeger晶格的数值模拟和微波实验验证了这一行为。 我们的研究结果提供了一个通用框架，以克服拓扑态的固有维度限制，其影响扩展到一般的波系统，如声学超材料。 显示英文摘要

摘要： Topological states, known for their robustness against disorder, offer promising avenues for disorder-resistant devices. However, their intrinsic spatial confinement at interfaces imposes geometric constraints that limit the scalability of topological functionalities. Here, we propose a strategy to overcome this limitation by using double-zero-index media to expand topological interfaces. Although occupying finite space, these media are optically equivalent to infinitesimal points, effectively altering the geometry of topological interfaces and breaking conventional bulk-edge correspondence. This strategy enables the spatial expansion of uniform topological states beyond their native interface, offering new possibilities for topological photonic devices. We have verified this behavior through numerical simulations and microwave experiments in a two-dimensional photonic Su-Schrieffer-Heeger lattice. Our findings offer a universal framework to overcome the inherent dimensional limitations of topological states, with implications extending to general wave systems such as acoustic metamaterials.