飞秒激光改性二维材料及超快波导激光研究

At present, with the promotion of graphene and similar layered two-dimensional (2D) materials research, they are gradually becoming a new kind of saturable absorbers in modern ultrafast laser technology, due to the unique structural characteristics, optical and nonlinear optical properties of these materials. In order to adapt the requirements of miniaturization and diversity of ultrafast laser devices and the improvement of their performances, it is necessary to modify 2D materials to optimize the optical absorption, nonlinear characteristics, mechanical properties, etc., and to control the band-gap of these materials, as well as to implement patterning processing. This project intends to use different parameters of femtosecond laser pulses to irradiate graphene, molybdenum disulfide and hexagonal boron nitride to induce these 2D materials to produce morphology and lattice structure in and around the irradiation region. Changes in properties such as band structure and optical nonlinearity, will be calculated based on previous femtosecond laser modification model and simulated by first-principles software, in order to study the physical mechanisms and regulating laws. And the femtosecond-laser-modified phenomenological model of three 2D materials will be established. Further the modified 2D materials will be utilized on the platform of ultrafast waveguide laser. The lasing performances will be explored and establish correspondence of modification results of the three materials. This project will provide theoretical basic and applied exploration, promoting techniques of femtosecond laser fabrication and modification.

当前，随着石墨烯和具有相似结构的层状二维材料的研究深入，由于这类材料独有的结构特性、光学和光学非线性性质，正逐步成为现代超快激光技术中最具潜力的饱和吸收材料。为了适应超快激光器件的小型化和多样性的要求并提高激光器的性能，需要对二维材料进行改性来增强材料的光学吸收、非线性特性、机械性等，并对二维材料进行带隙调控和图案化加工。本项目选取石墨烯、二硫化钼和六方氮化硼三种具有典型的能带、晶格结构的二维材料，拟利用不同参数的飞秒激光脉冲辐照诱导三种材料在辐照区域和附近产生形貌、晶格结构、能带结构、光学非线性等性质的变化，研究飞秒激光与二维材料相互作用的物理机理和调控规律，建立飞秒激光改性二维材料的唯象模型。将改性后的材料做饱和吸收体实现超快波导激光输出，并研究材料改性结果对激光参数的影响。本项目的研究成果将会对飞秒激光改性二维材料应用提供理论基础，促进飞秒激光在加工和改性领域发展。

本项目主要针对几种在现代超快激光器件和微纳光电子器件中极具应用价值的二维材料，研究其与飞秒激光的相互作用，并且应用于设计、加工制备和性能测试中。飞秒激光辐照作用将会影响材料的光学性质和电学性质变化，因而研究其改性效果和探索潜在的定向改性具有重要的理论价值和现实意义。.在项目执行期间，分别开展了材料改性引入的原子级缺陷，研究其对材料的缺陷能带结构、光致发光光谱、光学非线性，并通过第一性原理计算重构了原子缺陷，将实验和计算结果结合并建立原子级缺陷调控光学非线性的理论模型；开展了飞秒激光诱导材料光学非线性饱和研究，在飞秒激光辐照材料作用下，观测到了光学二阶非线性的饱和效应，建立了飞秒脉冲对材料非线性饱和调控的物理模型；开展了利用材料的原子级缺陷和光学非线性饱和，实现波导激光平台和全固态激光平台的稳定超快激光输出；开展了强压力引起的微观结构变化研究，建立了强场作用下的原子位移诱导的材料能带变化和光学性质改变；开展了微纳光学结构的超表面研究，通过光场调控手段对激光辐照过程中的偏振、光场分布的精细调控。.在项目执行期间，发表了SCI收录的学术论文15篇，培养硕士研究生六名，博士研究生三名。该项研究将为进一步开展的飞秒激光精密加工二维材料的光电器件和半导体器件提供理论基础和实验基础。