Free-space topological optical textures: tutorial
Yijie Shen, Haiwen Wang, Shanhui Fan
Abstract
Topological textures are well-established topics in condensed matter systems and nonlinear field theories. A typical example is the magnetic spin texture, which promises high-density data storage and information processing applications. With the recent development of nanophotonics and structured light, the topological optical textures, which are analogous to magnetic spin textures, can be created in linear electromagnetic fields with connections to solid-state physics but relying on radically different mechanisms. The emerging field of free-space topological optical textures has begun to show its ability to emulate diversified topologies in higher-dimensional light fields and open new directions of topologically protected information transfer. This article reviews the background of such topological textures, introduces a tutorial of fundamental theories for diverse topological textures in free space, and then provides perspective on the future potential applications to revolutionize our information society.