基于Al纳米结构的局域表面等离子体激元与激子耦合相互作用的超快动力学研究

Surface plasmon polaritons(SPPs) can break through the optical diffraction limit, so as to control the properties of absorption, fluorescence and Raman scattering, and it has a very wide application prospect. Relative to gold and silver, aluminum has a relatively long surface plasmon lifetime, can be achieved from the ultraviolet band to the near infrared band wide energy range of SPPs resonance. However, the understanding of the interactions mechanism between local surface plasmon polaritons based on aluminum nanostructures and materials are not clear and hinder the development of nanoscale devices. In this proposal, we plan to study SPPs-Exciton coupling interactions using aluminum-surface plasmonic and exciton hybrid systems prepared by aluminum local surface plasmon polaritons and dye molecules by time-resolved spectroscopy techniques. Try to find a strong experimental evidence for strong coupling in ultra-fast level and to reveal mechanism of energy transfer for weak coupling interaction, and further to realize the energy level controls for the dye molecules, these could lay the foundation for further applications.

表面等离子体激元可以突破光学衍射极限的限制，从而对吸收、荧光以及拉曼散射等性质进行调控，有着非常广泛的应用前景。相对于金和银，金属铝具有相对较长的表面等离子体激元寿命，可以实现从紫外波段到近红外波段宽能量范围内的表面等离子体激元共振。然而对铝特别是铝纳米结构的局域表面等离子体激元与物质相互作用机理的认识尚不清晰，阻碍了铝纳米结构纳米器件的发展。本项目以多种时间分辨光谱测试技术为手段，在制备成铝表面等离子体激元与激子耦合作用体系的基础上，利用特定的染料分子制备SPPs-Exciton强耦合杂化体系，探索通过调控铝纳米微结构实现SPPs-Exction强耦合杂化体系的新方法，并在超快层面上寻找实现强耦合作用的直接实验证据，揭示铝表面等离子体激元与分子弱耦合相互作用能量传递和演化的规律；实现对分子激发态弛豫跃迁的定向调控并阐明调控机理，为进一步的促进其应用奠定基础。

表面等离子体激元可以突破光学衍射极限的限制，从而对吸收、荧光以及拉曼散射等性质进行调控，有着非常广泛的应用前景。然而金属纳米结构的局域表面等离子体激元与物质相互作用机理的认识尚不清晰，阻碍了金属纳米结构纳米器件的发展。本项目完成过程中，观测到了高达860 meV的超强拉比劈裂，相应的劈裂峰几乎覆盖了光学波段。进一步的时间分辨动力学研究表明，由于快速的振动驰豫和无辐射衰减过程，上能带的驰豫动力学过程无法探测到；而由于等离子体激元快速衰减的原因，下能态的驰豫动力学过程和染料分子激子的本征驰豫动力学过程要快很多。同时，超强耦合的驰豫动力学过程和强耦合体系的动力学过程也存在明显的区别。以上研究内容，为基于金属局域表面等离子体激元的纳米光学器件的发展做出了有益的探索。