Originating from the studies of two-dimensional condensed-matter states, the concept of topological order has recently been expanded to other fields of physics and engineering, particularly optics and photonics. Topological photonic structures have already overturned some of the traditional views on wave propagation and manipulation. The application of topological concepts to guided wave propagation has enabled novel photonic devices, such as reflection-free sharply bent waveguides, robust delay lines, spin-polarized switches and non-reciprocal devices. Discrete degrees of freedom, widely used in condensed-matter physics, such as spin and valley, are now entering the realm of photonics. In this Review, we summarize the latest advances in this highly dynamic field, with special emphasis on the experimental work on two-dimensional photonic topological structures.

起源于二维凝聚态的研究，拓扑顺序的概念最近已扩展到物理学和工程学的其他领域，尤其是光学和光子学。拓扑光子结构已经推翻了一些关于波传播和操纵的传统观点。拓扑概念在导波传播中的应用使新型光子器件成为可能，例如无反射的急剧弯曲的波导，坚固的延迟线，自旋极化开关和不可逆器件。离散自由度已广泛应用于凝聚态物理中，例如自旋和波谷，现在正进入光子学领域。在这篇评论中，我们总结了这个高度动态领域的最新进展，