介电和金属人工微纳结构中元激发的输运和光电转换

In this project, we are going to investigate elementary excitations' transport and optoelectronic exchange in subwavelength artifical micro- and nano-structures of dielectrics and metals both in the experiments and in the theories. Firstly, we will explore how the elementary excitations, such as surface plasmon polaritons (SPPs) and magnetic plasmon polaritons (MPPs), influence the electromagnetic couplings. The origin of the electromagnetic couplings will be presented, and the plasmonic crystals, quasicrystals and even fractals will be achieved to manipulate the plasmonic band structures. In the second, we will explore the physical mechanism of electrical and magnetic resonances in all-dielectric metamaterials. The characterisic of the elementary excitations, such as surface polaritons (SPRs), and their effect on breaking the diffraction limitation will be figured out in this system. And a general principle will be given to realize low-loss subwavelength functional materials at optical frequencies. Thirdly, we will explore the mechanism of the exchange between light and surface plasmons in subwavelength metallic/dielectric micro- and nano-structures, and investigate how the plasmon excitations in metallic nano¬structures are engineered to enhance and provide valuable control over the emission of hot carriers. The novel plasmon-assited photoelectric effects and optical absorption are expected in the subwavelength metal/dielectric nanostructures. In the fourth, some new opto-electronic materials and devices will be designed and fabricated. The investigations will deepen the understanding of elementary excitations and their transport in the subwavlength artificial micro- and nano-structures, and also benefit in exploring the new information and energy carriers based on elementary excitations including SPPs, MPPs and SPRs.

本项目拟从实验和理论两方面研究亚波长金属和介电微纳结构中元激发的产生和输运规律及其在新型光电转化等方面的应用。深入探讨电磁波穿越不同组合和不同调制方式的金属和介电复合微纳结构时元激发（如表面等离激元与磁等离极化激元等）性质，构筑等离激元晶体、准晶体和分形，并实现其能带结构的操控；深入探讨全介电型亚波长微纳结构中电共振和磁共振的产生机制和调控手段，揭示全介电体系中表面极化子与突破衍射极限的物理关联，给出实现低损耗、光频响应的亚波长功能材料的原理与途径；深入探讨金属微纳结构中光与元激发相互转换的物理过程，借助元激发的产生与输运来实现热电子参与的高效率新型光电转换和光吸收效应；开发和研制基于元激发的新型光电功能材料和器件。通过这些研究期望揭示微纳结构中元激发输运与外场响应规律，实现新型高性能光电转换，探索基于元激发的新一代信息和能量载体。

在项目资助下，我们从实验和理论两方面系统研究了介电和金属人工微纳结构中元激发的产生和输运规律，并探讨了这些规律在光电转化等方面的应用，得到了一些很有意义的创新性结果，包括：第一, 构造出具有无序特征的新型微纳结构，揭示光和相关元激发与其相互作用新规律。创新性地构造出无序翻转超构表面，利用光学互易原理打破反射和透射的相位关联，将看似矛盾的漫反射与透射清晰成像的功能完美融合；创新性地将无序引入金属和介电微纳结构并进行工程化设计，首次实现光频等离激元的安德森局域化，证实其显著增强光与物质相互作用。第二，提出和实现了若干二维和三维新型亚波长结构，给出光与其相互作用的新原理和新效应，实现了对光的独特操控。首次提出基于几何标度相位构造超构表面的新原理，创新性地利用单一超构表面实现了多路径多种偏振态任意组合的同步输出；首次系统给出通过构造亚波长微纳结构来获得宽带电磁响应的几类方案。第三，构建了金属/二维材料/介电复合微纳结构，揭示了该体系中等离激元、激子、光学模式等多种元激发耦合效应，展示了热电子诱导的非线性光吸收增强；创新性地构建出少层有机-无机杂化钙钛矿亚波长结构，揭示该体系中Mie共振现象。第四，揭示了低损耗高折射率介质微纳结构中光捕获新原理和光电转换新规律，研制出几类性能优异的超薄光电探测器。第五，发展出纳米阵列结构制备新技术；发展出光电材料精准表征手段；并基于人工复合微纳结构研制出几类功能独特的新型亚波长光电材料和原型器件，等等。这些研究结果展示了介质和金属人工微纳结构中元激发输运与外场响应若干新规律，实现了基于元激发的新型高性能光电转换，给出了若干高性能光电功能新材料和原型器件，可应用于发展新一代信息技术、新能源、光与物质强相互作用等领域。. 有关工作在 Physical Review Letters、Physical Review X、Advanced Materials、Science Advances、Nature Communications、Nano Letters等国际著名学术期刊上发表SCI论文52篇，申请国家发明专利17项(已获得授权8项)。在国际重要学术会议上做邀请报告30余次。主办第五届等离激元光子学前沿国际会议。培养博士和硕士研究生43人。项目执行顺利, 很好地完成了原先的研究计划, 并根据国际发展的新热点, 适时地丰富了相关研究内容。