银纳米线上表面等离激元近场的超分辨成像

Plasmonic waveguide enables both the confinement of light to subwavelength scale and the propagation of surface plasmons (SPs) along the waveguide, which is the building block for future compact photonic circuits. Because of the spatial confinement of SPs on both side of the metal-dielectric interface, the usual optical microscope cannot reveal the plasmonic near field distribution beyond the diffraction limit. In this project, we will mainly investigate the near-field distribution of different SPs mode on silver nanowire by using the super-resolution imaging method which has the common ability to produce images with resolution below the diffraction-limit of light. By combining theoretical and experimental investigations, we will systematically study the interference of localized SPs and propagating SPs on the NW. We will also study the near field distribution of some other complex NW structures. The systematic researches here will not only facilitate the understanding of SPs filed distribution 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.

表面等离激元波导同时具有亚波长束缚特性和远距离传播特性，可以实现突破光学衍射极限的光传输，是未来亚波长集成光学器件的重要组成单元。然而由于表面等离激元的亚波长束缚特性，普通光学显微镜无法对表面等离激元波导电磁场近场精细信息直接探测，这大大限制了人们对表面等离激元传播特性的深入理解。本项目中我们提出利用单分子荧光超分辨成像技术对银纳米线波导上表面等离激元近场进行直接探测，从而分析不同表面等离激元模式的基本性质并观察它们之间的干涉现象，进而对更为复杂纳米线结构中近场特性进行深入研究。本项目不仅有助于理解纳米尺度下银纳米线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，为我国新一代高速信息技术的发展添砖加瓦。

金属纳米结构的表面等离激元模式可以将电磁场局域在结构表面，具有亚波长束缚特性和远距离传播特性，可以实现突破光学衍射极限的光传输。在青年基金的支持下，我们以银纳米线上局域和传播形式表面等离激元近场的探测和相关表征作为主要研究内容，同时也对各种其他金属纳米结构表面等离激元近场性质和应用进行了探索。具体的我们利用荧光分子超分辨成像方法实现了单根纳米线上近场的初步表征，探究了表面等离激元近场模式对远场点扩散函数的影响，利用金属纳米线上等离激元干涉效应实现了纳米线附近量子点纳米光源的选择性激发与超分辨探测，利用金属纳米线上传播表面等离激元的光热效应实现了表面等离激元热光调制器，利用相干散射成像和光热成像方法探究了基于金属纳米颗粒的超灵敏探测。项目的实施使我们对各种金属纳米结构的近场特性有了更加深入的认识。