各向异性多粒子散射系统和超平面结构中的多极子干涉效应

In this project, we propose to introduce refractive index anisotropy into multi-particle scattering systems and metasurfaces, and then study the influence of refractive index anisotropy on resonant multipolar excitations and interferences, which can be utilized to control the magnitudes, phases and polarizations of the optical fields. The investigations in this project will not rely on the conventional method that involves only electric and magnetic dipoles, but consider comprehensively the excitations and interferences of all electric, magnetic and toroidal multipoles of different orders and different natures. We will investigate systematically the interplay among multipolar interferences, refractive index anisotropy, and the geometric symmetry of the structures, revealing the induced influences on the optical phenomena of Fano resonances, generalized Kerker scattering, anapole mode excitation and scattering invisibility, and so on. Based on this we further study metasurfaces, the functioning mechanism of which in principle is deeply related to multipolar interference effects in multi-particle scattering systems. We will reveal how to employ refractive index anisotropy to achieve reflection and transmission phase control, wave polarization conversion, and manipulation of the reflection, transmission and absorption rates within anisotropic metasurfaces. The introduction of refractive index anisotropy into metasurfaces will help to provide much more flexibilities for a full manipulation of various light-matter interactions, which can play a significant role in optical communications and optical component designs in the near future.

本项目提出将折射率各向异性引入到多粒子散射系统以及超平面结构中, 以研究折射率各向异性对多极子共振激发的影响, 并进而探讨基于多极子干涉的光场振幅、相位及偏振态的调控。该研究不依赖于传统的局限于电偶极子和磁偶极子的方法，而是全面考虑不同类别、不同阶数的电多极子、磁多极子、以及环形多极子的激发和相互作用。我们将系统研究多极子干涉、折射率各向异性、结构的几何对称性三者之间的相互作用及其对法诺共振、广义柯克散射、暗极子激发和散射透明等光学效应的影响。以此为基础，我们进一步考察以散射系统中的多极子激发和干涉效应为基本机理的超平面结构，并研究在超平面结构中如何利用折射率各向异性实现光场的反射和透射相位调控，偏振态转换，和光场反射、透射及吸收率的控制。将折射率各向异性引入到超平面结构能为全面调控激光与物质相互作用提供更多自由度，并有望在未来的光通讯和光学器件设计方面发挥重要作用。

米散射理论是电磁学中最基本、最重要的理论之一，它几乎贯穿于所有光学分支,并在民用和国防等诸多技术领域发挥着不可替代的作用。项目负责人专注于米散射领域的基础理论研究,通过引入全新的数学物理工具发掘米散射背后隐藏的对称和奇点特性,并揭示众多相关基础概念间的内在关联以及深层的数学和物理结构。本项目期间创新成果包括: (1)引入庞加莱-霍普夫定理,提出全域米散射理论;(2)揭示偏振奇点、非厄米简并、贝里相位、连续域束缚态、欧拉示性数等核心概念间的本质关联；(3) 将奇点理论引入手性光学领域并系统揭示如何利用偏振奇点实现手性响应的理想极限；(4) 融合电磁对偶、电磁互易、宇称守恒等原理研究几何对称结构的散射特性; (5) 证明电磁波的轨道角动量和相位涡旋是两个截然不同的概念，两者之间没有必然关联；并系统揭示了相位涡旋拓扑荷的全域演化规律以及背后深层的数学结构。本项目期间共发表SCI论文25篇（一作/通讯论文17篇），包括3篇PRL，1篇PNAS，1篇Science Advances， 4篇Laser & Photonics Reviews等。项目负责人提出的概念和原理广泛渗透到声学、生物医学以及纯数学等众多学科分支, 并在辐射制冷、电磁天线、光学成像、光电探测器等应用领域发挥了关键作用，为实现更加精准和高效的光和物质相互作用调控提供基础理论支持。