Toroidal moments in artificial media have received growing attention and considered as a promising framework for initiating novel approaches to manage intrinsic radiative losses in nanophotonic and plasmonic systems. In the past decade, there has been substantial attention on the characteristics and excitation methods of toroidal multipoles—in particular, toroidal dipole—in 3D bulk and planar metaplatforms. The remarkable advantages of toroidal resonances have thrust the toroidal metasurface technology from relative anonymity into the limelight, in which researchers have recently centered on developing applied optical and optoelectronic subwavelength devices based on toroidal metaphotonics and metaplasmonics. In this focused contribution, the key principles of 3D and flatland toroidal metastructures are described, and the revolutionary tools that have been implemented based on this topology are briefly highlighted. Infrared photodetectors, immunobiosensors, ultraviolet beam sources, waveguides, and functional modulators are some of the fundamental and latest examples of toroidal metadevices that have been introduced and studied experimentally so far. The possibility of the realization of strong plexciton dynamics and pronounced vacuum Rabi oscillations in toroidal plasmonic metasurfaces are also presented in this review. Ultimate efficient extreme‐subwavelength scale devices, such as low‐threshold lasers and ultrafast switches, are thus in prospect.

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环形超光子学和元设备

人工介质中的环形矩已受到越来越多的关注，并被认为是一种有前途的框架，可用于启动新颖的方法来管理纳米光子和等离子体系统中的固有辐射损耗。在过去的十年中，人们对3D体和平面元平台中的环形多极子（特别是环形偶极子）的特性和激励方法给予了极大的关注。环形共振的显着优势已将环形超表面技术从相对的匿名性推到了风口浪尖，其中研究人员最近将重点放在开发基于环形超光子学和亚质子学的应用光学和光电亚波长装置上。在这项有重点的贡献中，描述了3D和平原环形超结构的关键原理，简要介绍了基于此拓扑实现的革命性工具。红外光电探测器，免疫生物传感器，紫外线束源，波导和功能调制器是迄今为止已引入并通过实验研究的环形元设备的一些基本和最新示例。本文还介绍了在环形等离子体激元超表面上实现强大的重子动力学和明显的真空拉比振荡的可能性。因此，极低效率的超亚波长标度器件，例如低阈值激光器和超快开关，将有望成为现实。功能调制器是到目前为止已引入并通过实验研究的环形元设备的一些基础和最新示例。本文还介绍了在环形等离子体激元超表面上实现强大的重子动力学和明显的真空拉比振荡的可能性。因此，极低效率的超亚波长标度器件，例如低阈值激光器和超快开关，将有望成为现实。功能调制器是到目前为止已引入并通过实验研究的环形元设备的一些基础和最新示例。本文还介绍了在环形等离子体激元超表面上实现强大的重子动力学和明显的真空拉比振荡的可能性。因此，极低效率的超亚波长标度器件，例如低阈值激光器和超快开关，将有望成为现实。