等离激元模式与光波导模式强耦合的超灵敏表征及应用

表面等离激元共振(SPR)模式与其他模式强相互作用的超灵敏表征是发展各类基于SPR的超高灵敏和超高分辨界面增强光谱技术的物理基础。目前，大多数与SPR模式进行强耦合作用的体系主要为有机分子、量子点和二维材料等，实验上对于介质光波导体系研究较少。同时，理论上对于SPR模式与光学波导模式强耦合作用的物理机制的解释仍不明确，并且传统的模式表征方法在信号检测灵敏度方面依然存在巨大的提升空间。本项目拟通过超快瞬态反射谱和超灵敏等离激元增强和频(PESFG)光谱等最新模式表征技术，探究等离激元纳米结构和光波导薄层组成的复合体系中强耦合作用的物理机制。通过引入半导体材料和非线性材料，探究强耦合区域复合体系中热电子转移的超快过程以及非线性材料光频率的转换效率。本项目研究对于优化设计微纳光子器件，实现基于强耦合作用的高效光电转化，提高PESFG器件的非线性转换效率等方面具有重要的实际意义。

The ultrasensitive characterization of the strong interaction between the surface plasmon resonance (SPR) modes and other modes lie in the physical basis for the development of all kinds of ultrasensitive and ultra-high resolution interface enhancement spectroscopy based on SPR. At present, most of the strongly coupled systems based on SPR modes are mainly organic molecules, quantum dots, and two-dimensional materials, whereas optical-waveguide systems remain lacking in experiment. At the same time, the theoretical explanation of the physical mechanism of strong coupling between SPR mode and optical waveguide mode is still unclear, and the traditional mode-characterization method still has a huge room for improvement in signal detection sensitivity. This project intends to explore the physical mechanism of strong coupling in the composite system composed of plasmonic nanostructures and optical waveguide thin layers by using the latest mode-characterization techniques such as ultrafast transient reflectance spectrum, ultrasensitive plasmon-enhanced sum frequency generation (PESFG) spectroscopy. By introducing semiconductor materials and nonlinear materials, the ultrafast process of hot electron transfer and the conversion efficiency of optical frequency of nonlinear materials in the strongly coupled region are investigated. This research has important practical significance in optimizing the design of micro-nano photonic devices, realizing efficient photoelectric conversion, and improving the nonlinear conversion efficiency of PESFG devices based on strong coupling effect.