A salient feature of solid-state quantum-Hall-type topological materials in two dimensions is the presence of conducting electronic edge states that are insensitive to scattering by disorder. Such unidirectional edge states have been predicted and observed in many other experimental settings, including photonics, mechanical, and acoustic structures. It is of great interest to understand how topological states behave in the presence of interparticle interactions and nonlinearity. Here, we experimentally demonstrate backscatter-immune unidirectional solitonlike nonlinear states on the edge of photonic topological insulators consisting of laser-written waveguides. As a result of the optical Kerr nonlinearity of the ambient glass, the solitonlike wave packet forms a long-lived quasilocalized coherent structure that slowly radiates power into the bulk and along the edge. The realization of solitonlike edge states paves the way to an understanding of nonlinear and interacting topological systems.

中文翻译：

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非线性 Floquet 拓扑绝缘体中单向孤立子状边缘状态的观察

二维固态量子霍尔型拓扑材料的一个显着特征是存在对无序散射不敏感的导电电子边缘态。这种单向边缘状态已经在许多其他实验环境中被预测和观察到，包括光子学、机械和声学结构。了解在存在粒子间相互作用和非线性的情况下拓扑状态如何表现非常有趣。在这里，我们通过实验证明了由激光写入波导组成的光子拓扑绝缘体边缘上的反向散射免疫单向类孤子非线性状态。由于环境玻璃的光学克尔非线性，类孤子波包形成了一个长寿命的准局域相干结构，它缓慢地将能量辐射到主体中并沿着边缘。类孤子边缘状态的实现为理解非线性和相互作用的拓扑系统铺平了道路。