Metasurfaces are planar photonic elements composed of subwavelength nanostructures, which can deeply interact with light and exploit new degrees of freedom (DOF) to manipulate optical fields. In the past decade, metasurfaces have drawn great interest from the scientific community due to their profound potential to arbitrarily control light. Here, recent developments of multiplexing and multifunctional metasurfaces, which enable concurrent tasks through a dramatic compact design, are reviewed. The fundamental properties, design strategies, and applications of multiplexing and multifunctional metasurfaces are then discussed. First, recent progress on angular momentum multiplexing, including its behavior under different incident conditions, is considered. Second, a detailed overview of polarization-controlled, wavelength-selective, angle-selective, and reconfigurable multiplexing/multifunctional metasurfaces is provided. Then, the integrated and on-chip design of multifunctional metasurfaces is addressed. Finally, future directions and potential applications are presented.

中文翻译：

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超表面增强的光复用和多功能。

超表面是由亚波长纳米结构组成的平面光子元件，可以与光深度相互作用并利用新的自由度（DOF）来操纵光场。在过去的十年中，超表面由于其任意控制光的巨大潜力而​​引起了科学界的极大兴趣。在这里，对多路复用和多功能超表面的最新发展进行了回顾，这些发展通过引人注目的紧凑设计实现了并发任务。然后讨论了复用和多功能超颖表面的基本属性，设计策略以及应用。首先，考虑了角动量复用的最新进展，包括其在不同入射条件下的行为。其次，对偏振控制，波长选择，角度选择，并且提供了可重构的多路复用/多功能超表面。然后，解决了多功能超表面的集成和片上设计问题。最后，介绍了未来的方向和潜在的应用。