电磁场近场特性研究

The study on near-field properties of electromagnetic field is one of the most important aspects of the electromagnetic researches, which can reveal the essence of the light-matter interaction. Restricted by the research techniques, the knowledge about the electromagnetic near-field is still quite limited. In this project, we will mainly investigate several novel properties of electromagnetic near-field related to practical applications, which include the polarization of the near-field, the large nonuniformity in highly enhanced near-field, and the near-field modulation in periodic structures. The studied system is focused on metallic nanostructures prepared using chemical synthesis, self-assembly and micro-/nano-fabrication techniques. By combining theoretical and experimental investigations, we will systematically study the following contents: the polarization of the near-field in metallic nanostructures; the near-field properties of chiral metallic nanostructures; the near-field modulation in metallic gratings; characterizing the near-field by using quantum dot imaging and scanning near-field optical microscope. The systematic researches for the novel properties of electromagnetic near-field in nanostructures will not only facilitate the understanding to light-matter interaction at the nanometer scale, but also promote the investigations of the devices for optical communication and signal processing, and boost the development of new-generation information technology.

电磁场的近场特性是电磁场研究的一个重要方面，可以揭示光与物质相互作用的本质。但由于受研究手段的限制，目前对近场特性的了解还很有限。本项目将重点研究电磁场近场的几个与应用相关的新奇特性，包括近场的偏振性、高增强近场的高度非均匀性和周期结构对近场的调制。研究体系将针对金属纳米结构，结合化学合成、自组装和微纳加工等样品制备手段，从理论和实验上系统地研究由表面等离激元导致的新奇的近场特性；研究金属纳米结构中表面等离激元电磁场的近场偏振特性；研究手性金属纳米结构的近场特性；研究周期性金属纳米光栅结构对近场的调制；利用量子点成像和扫描近场光学显微镜对近场特性进行表征。对纳米结构中电磁场近场新奇特性的深入研究，不仅有助于理解纳米尺度下结构与光场相互作用的特点，更可促进亚波长光信息通讯和信号处理单元器件的研制，推动我国新一代高速信息技术的发展。

电磁场的近场特性是电磁场研究的一个重要方面，可以揭示光与物质相互作用的本质。本项目围绕微纳结构光学性质的近场调控、产生与传输，重点探索微纳材料/结构的设计、制备、调控方式以实现近场光学特性的调控与探测。我们通过发展等离激元器件的理论、制备与表征技术，在亚波长片上光信息器件、增强光谱和传感、激子-等离激元相互作用、纳腔非线性效应、手性调控等多个方面取得重要进展。通过金属纳米颗粒/二维材料/金属镜面的复合体系、等离激元微纳结构/半导体光电器件等一系列复合体系的可控构筑和荧光/非线性/光电特性/手性光谱的探测，对纳腔中光场与激子相互作用、纳米材料中的增强非线性效应和产生机理、光生热载流子的弛豫机制等热点问题进行了研究。在片上等离激元亚波长波导、可控制备的等离激元纳腔超快电致发光光源、高效光热电探测器、低阈值等离激元激射、亚皮米纳腔高精度传感、空腔增强拉曼微流控光学检测、高效率片上非线性光学器件、手性拉曼信号的定向耦合器、基于二维材料的室温谷编码信息器件等实现了若干突破。