Metasurfaces, the ultrathin, 2D version of metamaterials, have recently attracted a surge of attention for their capability to manipulate electromagnetic waves. Recent advances in reconfigurable and programmable metasurfaces have greatly extended their scope and reach into practical applications. Such functional sheet materials can have enormous impact on imaging, communication, and sensing applications, serving as artificial skins that shape electromagnetic fields. Motivated by these opportunities, this progress report provides a review of the recent advances in tunable and reconfigurable metasurfaces, highlighting the current challenges and outlining directions for future research. To better trace the historical evolution of tunable metasurfaces, a classification into globally and locally tunable metasurfaces is first provided along with the different physical addressing mechanisms utilized. Subsequently, coding metasurfaces, a particular class of locally tunable metasurfaces in which each unit cell can acquire discrete response states, is surveyed, since it is naturally suited to programmatic control. Finally, a new research direction of software‐defined metasurfaces is described, which attempts to push metasurfaces toward unprecedented levels of functionality by harnessing the opportunities offered by their software interface as well as their inter‐ and intranetwork connectivity and establish them in real‐world applications.

中文翻译：

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迈向智能超颖表面：从全局可调超颖表面到具有嵌入式控制器网络的软件定义超颖表面的进步

超表面，超薄的2D版本的超材料最近因其操纵电磁波的能力而引起了人们的关注。可重构和可编程超颖表面的最新进展大大扩展了它们的范围，并进入了实际应用。这种功能性片状材料可对成像，通信和传感应用产生巨大影响，它们可作为可形成电磁场的人造皮肤。受这些机会的激励，这份进度报告回顾了可调谐和可重构超颖表面的最新进展，突出了当前的挑战并概述了未来研究的方向。为了更好地跟踪可调形超表面的历史演变，首先提供对全局和局部可调超表面的分类以及所使用的不同物理寻址机制。随后，对编码超表面进行了调查，这是一类特殊的局部可调超表面，其中每个单位单元都可以获取离散的响应状态，因为它自然地适合于程序控制。最后，描述了软件定义的元表面的新研究方向，它试图通过利用其软件接口及其内部和网络内部连接提供的机会，将元表面推向前所未有的功能水平，并在实际应用中建立它们。由于每个单位单元都自然地适合于程序控制，因此对其中每个单位单元可以获取离散响应状态的特定类型的局部可调超表面进行了调查。最后，描述了软件定义的元表面的新研究方向，它试图通过利用其软件接口及其内部和网络内部连接提供的机会，将元表面推向前所未有的功能水平，并在实际应用中建立它们。由于每个单位单元都自然地适合于程序控制，因此对其中每个单位单元可以获取离散响应状态的特定类型的局部可调超表面进行了调查。最后，描述了软件定义的元表面的新研究方向，它试图通过利用其软件接口及其内部和网络内部连接提供的机会，将元表面推向前所未有的功能水平，并在实际应用中建立它们。