紫外波段铝表面等离激元的阴极荧光光谱研究

Compared with surface plasmons from near-infrared to visible range in gold and silver, ultraviolet (UV) surface plasmons in aluminum nanostrucutures possess great potential applications in UV photocatalysis, sensor and photoelectronics. However, the research on aluminum plasmons based on traditional far-field methods is restricted by the diffraction limit of light. It is still an unsolved issue to obtain the distribution of local density of photonic states of aluminum nanostructures in real space, which should be a key stone for both understanding UV plasmons in aluminum nanostructures and designing for the applications of aluminum plasmons. In this project, based on cathodoluminescence, the surface plasmons of aluminum nanostructures will be investigated. Moreover, taking advantage of the unique properties of electron beam excitation, new experimental schemes are going to be designed to study the coupling between surface plasmons in different aluminum nanostructures. Furthermore, the ultrafast properties of propagating plasmons of aluminum will also be explored by the coupling between emitters and plasmons. Overall, by the systemic study of aluminum plasmons in this project, not only the physical mechanism such as dissipation, coupling of aluminum plasmons can be deeply understood, but also the near-field related applications of UV plasmons in information technology, chemistry and biology can be well designed.

与可见至近红外波段的金、银表面等离激元相比，紫外波段的铝表面等离激元在紫外光催化、生物化学传感、光电子学等方面具有重要的应用价值。然而，对于基于铝的紫外表面等离激元的研究，传统的远场光学手段一直受到衍射极限的限制，如何得到铝的纳微结构的局域光子态密度实空间分布对于理解和设计紫外表面等离激元近场相关的应用将起到关键作用。在本项目中，我们拟采用基于电子显微镜的阴极荧光光谱技术，研究铝的纳微结构的紫外至可见波段的表面等离激元的近场特性，并利用电子束定点激发的优势设计新型的实验探测配置，探索耦合铝纳微结构中表面等离激元相干、耦合的调控以及近场-远场的控制，进一步通过与发射体耦合的方式研究传播铝表面等离激元的超快时间特性。通过本项目的研究，我们不但能充分理解紫外波段铝表面等离激元的损耗、耦合等物理机制，而且能对紫外波段铝等离激元在信息、化学和生命等领域近场相关的应用设计提供基础。

与可见至近红外波段的金、银表面等离激元相比，紫外波段的铝表面等离激元在紫外光催化、生物化学传感、光电子学等方面具有重要的应用价值。在本项目中，我们主要采用了基于电子显微镜的阴极荧光光谱技术，研究了铝纳微结构（一字型，十字型，开放腔及金属/介质/金属三层结构等）的紫外至可见波段的表面等离激元模式衍化规律，实现了其实空间的亚波长近场成像。同时，我们着重探索了耦合铝纳微结构中表面等离激元相干、耦合效应，并且研究了铝等离激元与发射体从弱到强耦合的效应；进一步发展了倏逝场与自由电子相互作用的基础理论，研究了自由电子与倏逝场间的角动量转移。通过本项目的研究，我们不但充分理解紫外波段铝表面等离激元的物理机制，而且为其在强光-物质相互作用方面的应用提供了基础。