基于黑磷量子点的紫外可饱和吸收体研究

The saturable absorber is the key for ultrashort pulse generation in mode-locking laser techniques. The low-dimensional materials, such as carbon nanotubes, graphene, transition metal dichalcogenides, black phosphorus, have been used for application as semiconductor saturable absorber mirrors from Near-infrared to Mid-infrared wavelength region. However, due to the lack of suitable ultraviolet saturable absorption materials, the ultraviolet mode-locking laser technique meets difficulties. In this project,black phosphorus quantum dots (BPQDs) will be adopted as alternative candidates for ultraviolet saturable absorber mirrors. High-quality composite films based on BPQDs will be fabricated and their ultraviolet optical nonlinearities will be studied. In addition, based on BPQDs, the basic nonlinear optical parameters and relationship between structure and property will be obtained, the performance of ultraviolet saturable absorbers will be optimized, and ultraviolet ultrashort pulse generation will be explored for application. At last, this project would play the key role in the motivation of the development of ultraviolet ultrashort pulse lasers and the application of ultraviolet nanophotonic devices.

利用可饱和吸收体锁模器实现激光锁模是获得超短激光脉冲的关键技术。基于低维材料（碳纳米管、石墨烯、过渡金属硫族化合物、黑磷等）的半导体可饱和吸收体谐振腔研究在近红外和中红外波段已经取得进展。受限于缺乏合适的紫外可饱和吸收体材料，紫外激光锁模技术亟须突破。本项目提出以黑磷量子点作为紫外可饱和吸收体锁模器应用的候选材料，制备高品质黑磷量子点复合薄膜，研究其紫外超快非线性光学效应，获得非线性光学基本参数及其结构-性质关系，优化基于黑磷量子点的紫外可饱和吸收体，探索在应用层面获得近紫外波段黑磷基超短激光脉冲。本项目对推动紫外超快激光光源发展及紫外光子器件应用具有重要意义。

本项目基本按照原计划进行，一方面，根据项目计划成功制备黑磷量子点样品，对样品做相关的形貌、线性光学表征，为了提高黑磷量子点稳定性并制备基于黑磷量子点的可饱和吸收体，采用sol-gol方法制备了黑磷量子点凝胶玻璃薄膜结构，随后进行紫外波段非线性光学实验测试。探索了黑磷量子点凝胶玻璃在紫外波段的非线性吸收性能。另一方面，关于类黑磷材料的基本性质尤其是非线性光学性质开展了系列研究，包含了碲烯、锗烯，Bi2Se3，NbC2等。同时，依托项目进一步升级了实验室非线性光学表征系统，搭建了微区非线性光学表征系统，为下一步工作奠定基础。