微区多层黑磷纳米片非线性光学表征及超快光子应用研究

Fiber lasers have shown unique advantages in industrial laser application, due to its high electro-optic conversion efficiency, good beam quality, good integration and low maintenance requirements. During the realization of ultrashort pules generation process for fiber lasers, the saturable absorption effect is a key technology. Two-dimensional materials possess ultrathin structural features, which can be used to achieve lightweight, high-efficiency new fiber laser. With the change of thickness, the bandgap of black phosphorous is tunable from 0.3-2.0eV..It covers the near-infrared telecommunication band (1550nm), which suggest that black phosphorus would be an excellent candidate for fiber laser application. There have been some black phosphorus nonlinear optical reports. However, most of them focus on the nonlinear optical of random black phosphorus nanosheet collective rather than individual nanosheet. That didn’t make full use of the ultrathin features of.multi-layer black phosphorus. This project intends to realize micro-zone high resolution nonlinear optical characterization by modifying femtosecond intensity-scanning system (fs-I-Scan). Besides, using high-precision two-dimensional material transfer system to improve the black phosphorus transfer accuracy to the optical fiber end face. As a result, the performance of saturable absorber would be the controllable improvement. Through the implementation of this project, we will establish a set of high-precision micro-zone nonlinear optical characterization and transfer system to effectively improve the performance of the fiber laser passive mode-locked device。

光纤激光器有着电光转换效率高、光束质量好、维护要求低等特点，在工业激光应用领域逐渐表现出优势。在光纤激光器应用过程中，可饱和吸收是实现激光锁模的关键技术。利用二维可饱和吸收材料超薄的结构特征，有望实现轻量级新型光纤激光器。多层黑磷带隙特征（0.3-2.0 eV）覆盖了光学调制近红外光学通讯波段，使其成为光纤激光应用优异备选材料。黑磷非线性光学表征和应用研究大多数体现的是黑磷纳米片的群体效应，未充分表征黑磷本证的可饱和吸收特性。本项目利用改进的飞秒激光强度扫描（femtosecond intensity -scan，fs-I-Scan）系统，实现高分辨微区多层黑磷材料非线性光学表征。采用高精度二维材料转移系统，提高黑磷纳米片转移至光纤端面的精度，实现被动激光锁模可饱和吸收器性能可控提高。通过本项目研究内容的实施，我们将建立一套高精度微区非线性光学表征系统，提高光纤激光器性能。

本项目按照原计划执行，搭建了微区Z-scan光学测试平台，利用该系统进行了样品的非线性光学表征和超快光学研究。并且在搭建的微区Z-scan系统基础上，升级了自动扫描光强和自动扫描不同区域的新功能。该系统可以实现更加系统全面的光学成像和三阶非线性光学性质表征。同时利用该系统进行了一系列研究：（1）利用微区Z-scan系统研究了二维WS2/石墨烯范德华异质结宽波段可饱和吸收增强的效应，并结合载流子转移模型和非绝热分子动力学计算确定了其增强机理；（2）首次报导了过渡金属碳氮化合物典型代表二维碳化铌非线性光学吸收效应，并且基于超快光学和第一性原理计算研究确定了尺寸和波长对非线性光学响应的调控作用；（3）研究了类黑磷材料碲烯和锗烯的超快非线性光学特性，表征了其宽波段的非线性吸收性质，并结合动力学测试和第一性原理理论计算解释了波长相关的光学漂白物理过程；（4）在前期对机理研究的基础上，进行了进一步的超快光子学应用研究，分别实现了原子层厚度PtSe2超构表面光场调控和基于POM修饰黑磷纳米片的纳米光子学应用。