金属纳米颗粒超窄线宽表面等离激元多维度动态调控研究

表面等离激元因其优异的空间局域与电场增强特性而备受关注。然而，以金属为载体的表面等离激元，一方面因其较高的本征损耗具有较宽的共振线宽，另一方面其结构的可重构性与可调谐性较差，加工完成后结构参数难以动态调节，从而限制了其器件性能与实际应用。针对该问题，本项目基于微流谐振腔-金属纳米颗粒的复合结构，建立表面等离激元与光学腔模式耦合的物理模型，深入研究近场相互作用对金属纳米颗粒表面等离激元寿命、线宽、共振强度、空间局域以及辐射与非辐射衰减速率等行为的影响，获得并阐明表面等离激元线宽的压缩机制；利用液相材料、金属纳米颗粒、光力的协同作用，寻求多物理场下表面等离激元动态调控的有效方法，设计、制备并最终实现具有超窄线宽且在空间、光谱、极化、强度等多个维度上动态可调的表面等离激元器件。本项目既有利于该领域基础研究的开展，又可为发展超紧凑、高性能、可调控、多功能的新型表面等离激元器件提供新的思路。

Owing to their fascinating properties of strong energy localization and significant electric-field enhancement, surface plasmon polaritons (SPPs) have attracted considerable attentions. However, the metal based SPP not only suffers from its relatively broad resonance linewidth due to the inherent high loss, but also has relatively poor reconfigurability and tunability. Once the metal nanostructure has been fabricated, the material properties and structure parameters are difficult to adjust. Therefore, the performance of a SPP-based component or device is deteriorated, and its practical application is also limited. To address this issue, based on a hybrid structure consisting of metal nanoparticle and microfluidic cavity, we’ll theoretically build the coupling model between the SPP mode and the resonant mode in the microfluidic cavity. We will thoroughly investigate the relationship between the near field interaction and the SPP behaviors of the metal nanoparticle, including plasmon lifetime, linewidth, intensity, localization, radiative decay rate and non-radiative decay rate. We will also obtain and further explain the mechanism to reduce the resonance linewidth of the SPPs. Meanwhile, by fully utilizing the synergetic efforts of microfluid, SPPs and optical force, the effective methods to realize dynamic control of the SPPs in multiple dimensions will be investigated. Furthermore, we will design, fabricate and finally realize a dynamic plasmonic device with both ultra-narrow linewidth and large tunability in multiple dimensions including spatial localization, spectrum, polarization and intensity. This project will not only be beneficial to basic scientific research, but also may open new doors for developing ultra-compact and multifunctional plasmonic devices with high performance and dynamic control capability.