具有奇异力学特性的可重构电磁异向介质合成及机理研究

Reconfigurable metamaterial is a frontier research area of metamaterials and aims to realize multiple optical functions within a single metamaterial device. In this project, inspired by the design concept of allotrope in chemistry, we propose a strategy of synthesis and reconstruction of electromagnetic allotropes by use of a rigid origami technology with extraordinary mechanical properties, in order to improve the deformation ability of metamaterials and the dynamic ranges of electromagnetic responses. The project starts with the microscopic physical mechanism of artificial meta-atoms and explores the influence mechanism of space attitudes and geometric dimensions on the electromagnetic response of meta-atoms. By adopting the means of structural coding and cluster analysis, we will investigate the relationships between the spatial arrangements of meta-atoms and the macroscopic electromagnetic properties of metamaterials, and clarify the synthetic mechanism of artificial electromagnetic allotropes. Subsequently, the origami spatial deformation method will be introduced to reconstruct the electromagnetic allotrope. The influence of the origami’s lattices and the artificial atomic arrangements on the electromagnetic phase transition will be carefully analyzed. Finally, the mechanism of electromagnetic phase transition will be clarified and a general strategy will be established to achieve both extraordinary mechanical properties and reconfigurable electromagnetic performance, achieving dynamical switching between conductor, dielectric, chiral and bianisotropic phases. As far as we know, it is the first combination of the concept of chemical synthesis and the design method of extraordinary mechanical structures in metamaterial design, thus providing a new avenue towards reconfigurable optical devices.

可重构异向介质是人工电磁媒质的前沿方向，目标是在同一异向介质中实现多种光学功能。本项目针对跨维度几何形变困难的关键问题，开展可重构异向介质研究，借鉴化学同素异形体的思想，拟利用具有奇异力学特性的刚性折纸结构，提出人工电磁同素异形体的合成及重构策略，提高异向介质的形变能力和电磁响应动态范围。项目从人工原子的微观物理机理入手，探索空间姿态和结构尺度对电磁响应的影响机制。以及结构编码和聚类分析手段，寻找原子空间排列与宏观电磁性质之间的关联，阐明人工电磁同素异形体的合成机理。利用折纸形变方法进行同素异形体的重构，分析晶格结构和人工原子分布对电磁相变的作用机理，实现同时具有负泊松系数等奇异力学特性又能在导体、介质、手性和双各向异性等不同电磁特性之间快速重构的新型异向介质媒质。本项目首次将化学合成思想和力学特异结构设计方法结合起来，应用在人工电磁媒质设计，为可重构光学器件的设计提供了一个新的思路。

折纸异向介质是结合人工电磁结构与几何折叠变形的一个新兴研究领域，提供可变形、可延展电磁功能材料与器件。本研究聚焦折纸异向介质中人工原子的手性响应机理，探索人工原子结构、三维排列方式对宏观异向介质电磁响应的影响规律，开展人工电磁同素异形体的重构理论和器件研究。本研究揭示了倾斜偶极子超构金属光栅的宽带双面散射效应原理、双各向异性人工原子中自由电子辐射极化调控原理、光子异质结构中的自旋翻转分束机理，构建了机械调控折纸反射墙、自适应角度调控折纸回射光栅、非对称辐射折纸超表面等电磁功能器件重构方案，采取仿真与实验相结合的方式进行验证。本研究取得的成果，可为空间电磁波调控提供技术支撑，推动电磁频谱控制能力的进一步提升。