等离激元-激子耦合体系的基元序构及非线性光学效应的共振增强研究

非线性光学（NLO）对推动未来信息技术的发展意义重大。根据入射光场是否与物质发生能量交换，NLO效应分为参量和非参量过程。很长时期，相较于前者，后者的研究相对滞后。近十年来，受益于二维材料和超快技术的突破，后者亦获强劲发展，但仍存在材料体系较为单一、物理机制不明等瓶颈科学问题。基于此，本项目提出：突破现有材料体系的制约，以具有显著等离激元特征的贵金属纳米阵列为基底，沉积具有丰富激子效应的有机半导体酞菁/卟啉共价有机框架化合物，以二者为物质平台，实现等离激元-激子耦合体系的基元序构，发展介观系统和人工微结构的构筑新技术，挖掘针对NLO非参量过程的新型、高性能材料。发展微区、实时、在线Z扫描和泵浦探测新技术，从时间和空间两个维度深入探究NLO非参量过程的产生机制，揭示等离激元-激子的耦合和共振效应对NLO的强化机理。发展光与物质相互作用理论，丰富NLO和凝聚态物理的学科内涵。

The development of nonlinear optics (NLO) is important for future information technology. According to whether the incident light behaves energy exchange with the media, NLO can be divided into parameter process and nonparameter process. Compared with the former, the latter developed lagging behind due to the lack of theory model and investigation technique. The situation has been improved in the last decade, owing to development of two-dimensional materials and superfast laser technique. However, challenges remain: material systems are limited; NLO mechanisms are slurred. To deal with these challenges, in this project, we propose: select noble metal nanoparticles with distinctive localized surface plasmons and phthalocyanine/porphyrin covalent organic frameworks (COFs) with remarkable exciton effect as functional elements and we construct plasmon-exciton coupling system. We therefore develop an efficient "bottom-up" approach for mesoscopic systems and artificial microstructures. We investigate the interaction of ultra-short pulse laser with this sort of ordered materials and the resulted NLO responses. We illustrate how the coupling and resonant between noble metal nanoparticles surface plasma and phthalocyanine/porphyrin COFs excitons influence the NLO behaviors of the ordered composite system. We will also develop a new technique for the micro-, real-time, on-line z-scan and pump-probe measurements. This work is important for the development of high performance NLO materials, and it will also promote the theory of interaction between laser and materials and enrich connotation of NLO and condensed physics.