基于超表面的电磁表面波调控研究

The arbitrary control of electromagnetic (EM) waves is always a dream of human beings, but natural materials exhibit limited EM control abilities. To solve this challenge, people have recently proposed the concept of EM metasurfaces and realized many novel effects, such as generalized Snell's law, high efficiency surface wave (SW) generation, etc. However, the previous metasurface-related researches mainly focus on the manipulations of three-dimensional propagating wave. Supposing that the concept of metasurfaces is extended to SW control, a new research field will be opened up. The applicant has accumulated many experiences in this field and has proposed to utilize metasurface to solve the issue of high efficiency SW excitation. Next, we plan to adopt theoretical analysis, numerical simulations and experimental measurements to investigate the wave-front controls of SWs, including the following parts of researches: 1) Clarifying the mechanism to manipulate the amplitude and phase of SWs and building up the foundations of SW controls; 2) Investigating the anomalous reflection effect of SWs and the generation of one-dimensional SWs and 3) complex wave-front manipulations of SWs, and achieving preliminarily several goals of SW controls; 4)Investigating the far-field scattering problem in SW manipulations, and understanding their origins to achieve the SW scattering manipulations. These researches will construct new concepts of surface wave manipulations and guide to building up the ideal near field environments, that may inspire many SW related applications.

自由调控电磁波一直是人们的梦想，然而自然材料的电磁调控能力非常有限。为解决该挑战，最近人们提出电磁超表面的概念，实现了广义斯涅耳定律、高效率耦合表面波等众多奇异物理效应。然而，以往的超表面研究主要关注于三维传输波调控，若把超表面的概念应用至表面波调控，这将打开一个全新领域。申请人在超表面领域具有丰富的经验，曾提出利用超表面初步解决表面波的高效率激发问题，计划结合理论分析、数值模拟和实验测量进一步开展表面波的波前调控研究：1）表面波的振幅和相位的调控机理研究，奠定表面波调控的基础；2）表面波的奇异反射和一维表面波转化研究，3）表面波的复杂波前调控研究，初步实现若干表面波调控的目标；4）表面波调控中的远场散射问题，理解散射损耗的来源并探索如何调控散射波。这些研究将建立超表面调控表面波的新机制，指导人们构建理想的近场光学环境，为表面波的相关应用提供全新的平台。

本项目主要研究基于超表面实现对电磁表面波的自由调控，取得了以下几方面的成果：1）研究了表面波在不同媒质界面的远场散射效应，提出利用超表面实现高效率调控表面波远场辐射的新思路；2）提出利用单个超表面同时实现手性依赖的高效表面波激发及波前调控的新概念；3）提出一种基于超表面实现矢量光场构建技术，实验实现了在圆偏振光激励下的复杂远场矢量光场以及涡旋径向偏振表面波激发；4）利用超表面实现高效率自旋光场调控，实验实现了光子自旋霍尔效应、聚焦\偏折、双全息成像等调控功能。在本项目资助下，共发表学术论文19篇，包括4篇Light: Science & Applications，2篇 Advanced Science，1篇Advances in Optics and Photonics，1篇 Research，1篇Science Bulletin，1篇Advance Optical Materials，3篇Nanophotonics等高水平期刊论文，总影响因子224.5，共被SCI引用754次，5篇论文入选ESI高被引论文。项目负责人作为第二完成人获得“2019年度国家自然科学二等奖”，入选“2020 Rising Star of Light”，入选“2020、2021爱思唯尔中国高被引学者”，5次担任国际会议分会主席/程序委员会委员，28次在SPIE/COS Photonics Asia等国际会议上做邀请报告。