介观结构-二维材料激子极化激元的时空分辨及其在光子器件中的应用

The study of the interaction between photons and material excitons in mesoscopic scale is an important branch of nanophotonics. Nowadays, there are two important problems in this field internationally. Firstly, the exciton binding energy of traditional materials is limited, which leads to that the very few configurations based on exciton polaritons can be operated at room temperature. The second point is that the spatial physical images and the relaxation dynamic process of the interaction are not clear. This project is made a breakthrough from three aspects: the mesoscopic structure design of two-dimensional material exciton polaritons, exploration of the physical image and relaxation dynamics, and related preliminary applications. Combining with the metal surface plasmon waveguides and periodic arrays, we build different configurations of the mesoscopic structures-two-dimensional material exciton polaritons. Further using femtosecond-nano spatio-temporal resolution photoemission electron microscopy, we make a deep study of the exciton polaritons coupling with near field steady-state distributions and relaxation time of dynamic process, and reveal the new phenomenon and physics of the interaction between photons and semiconductor materials excitons in the strong coupling condition. These results will be of great significance for the development of exciton polaritons and the new frontiers opening of micro-nano photonics.

介观尺度下光子与物质材料激子的相互作用的研究是纳米光子学的重要分支。目前国际上在该领域存在两个难题：一是受材料激子结合能的瓶颈限制，室温条件下基于激子极化激元的构型很少；二是相互作用的空间物理图像以及驰豫动力学过程不清晰。本项目计划从介观结构-二维材料激子极化激元的结构设计，物理图像和驰豫动力学过程以及相关调控应用的初步探究这三个方面分别进行突破，结合金属表面等离激元周期阵列和传播波导，建立设计不同构型下的介观结构-二维材料激子极化激元的微纳结构模型；进一步利用具有飞秒-纳米时空分辨的光发射电子显微镜，深入研究了解不同构型的激子极化激元的耦合稳态近场空间分布以及弛豫时间动力学过程，揭示强耦合条件下介观结构中光子与半导体材料中激子相互作用的新现象新物理。这些成果将对激子极化激元器件的发展以及微纳光子学的新前沿的开创具有重要意义。

本项目围绕介观结构—二维材料激子极化激元开展研究，证明了非对称硫化钨激子极化激元双周期光栅中存在低功率快速响应全光可调的尖锐束缚模共振模式，实现了基于范德瓦尔斯材料周期纳米阵列的全光可调局域激子极化激元超材料，实现了利用覆盖超薄二维激子J聚体有机分子聚合物的平面介质硅非对称光栅结构激子和光子的强耦合，提出了基于二氧化钛纳米线和过渡金属硫属化合物的长传输距离超紧凑传输型激子极化激元，验证了基于介质回音壁模式纳米盘阵列和二维过渡金属硫属化合物激子材料的一维SSH拓扑极化激元，同时利用泵浦-探测实验装置测试了二维材料激子极化激元的时间动力学响应，利用光发射电子显微镜对激子极化激元进行了近场观测。本项目对激子极化激元光与物质相互作用的基础研究以及光器件的应用都具有重要意义。