Sun Yeyang, Hou Xiangrui, Wan Tuo, Wang Fangyu, Zhu Shiyao, Ruan Zhichao, Yang Zhaoju
School of Physics and Zhejiang Province Key Laboratory of Quantum Technology and Device, Zhejiang University, Hangzhou 310027, Zhejiang Province, China.
State Key Laboratory for Extreme Photonics and Instrumentation, Zhejiang University, Hangzhou 310027, China.
Phys Rev Lett. 2024 Feb 9;132(6):063804. doi: 10.1103/PhysRevLett.132.063804.
Non-Hermitian skin effect and photonic topological edge states are of great interest in non-Hermitian physics and optics. However, the interplay between them is largely unexplored. Here, we propose and demonstrate experimentally the non-Hermitian skin effect constructed from the nonreciprocal flow of Floquet topological edge states, which can be dubbed "Floquet skin-topological effect." We first show the non-Hermitian skin effect can be induced by structured loss when the one-dimensional (1D) system is periodically driven. Next, based on a two-dimensional (2D) Floquet topological photonic lattice with structured loss, we investigate the interaction between the non-Hermiticity and the topological edge states. We observe that all the one-way edge states are imposed onto specific corners, featuring both the non-Hermitian skin effect and topological edge states. Furthermore, a topological switch for the skin-topological effect is presented by utilizing the phase-transition mechanism. Our experiment paves the way for realizing non-Hermitian topological effects in nonlinear and quantum regimes.
非厄米趋肤效应和光子拓扑边缘态在非厄米物理与光学领域备受关注。然而，它们之间的相互作用在很大程度上尚未得到探索。在此，我们提出并通过实验证明了由弗洛凯拓扑边缘态的非互易流构建的非厄米趋肤效应，可将其称为“弗洛凯趋肤 - 拓扑效应”。我们首先表明，当一维（1D）系统受到周期性驱动时，结构化损耗可诱导非厄米趋肤效应。接下来，基于具有结构化损耗的二维（2D）弗洛凯拓扑光子晶格，我们研究了非厄米性与拓扑边缘态之间的相互作用。我们观察到所有单向边缘态都被施加到特定角落，兼具非厄米趋肤效应和拓扑边缘态的特征。此外，利用相变机制提出了一种用于趋肤 - 拓扑效应的拓扑开关。我们的实验为在非线性和量子领域实现非厄米拓扑效应铺平了道路。
