石墨烯超快被动锁模机理的分析及实验研究

Graphene exhibits peculiar properties on electronics and nonlinear optics, which makes it have significant applications on physics, chemistry and so on. At present, the application research of graphene on ultra-fast photonics, especially on ultra-fast passive mode-locking, has attractted much international attention. However, the theoretical and experimental study on the mechanism of the ultrafast passive mode-locking based on grahene have not been reported yet. In this project, in order to solve the problem on mode-locking pulse unstablity, the study will be explored and investigated as follows: (1) Optimal designing the waveguide sturcture and graphene material for improving the properties of graphene saturable absorber; (2) Fabricating graphene saturable absorber and exploring feasible and effective ways to micro-manufacture waveguide and transfer graphene material on fiber waveguide; (3) Exploring and investigting the physical machanism of ultrafast passive mode-locking based on graphene; (4) Theoretically and experimentally studing the infulence of fiber dispersion, nonlinearity, the ultrafast carrier dynamics in graphene, saturable absorption intenisty of graphene, modulation depth in graphene etc. on mode-locking pulse unstablity. Finally, we can obtain stable ultra-short pulse.

石墨烯具有优异的电学性能和非线性光学特性，在物理、化学等很多领域都有着重要的应用价值。目前，对石墨烯在超快光子学，尤其在超快被动锁模中的应用研究已成为备受瞩目的国际前沿和热点。但是，从理论和实验结合的角度来分析石墨烯超快被动锁模机理方面的研究尚未见报道。本项目针对超快被动锁模过程中输出脉冲不稳定这一问题，拟开展以下理论与实验方面的研究：（1）以提高石墨烯饱和吸收体性能为目标，对波导结构、石墨烯材料进行综合优化设计；（2）制备石墨烯饱和吸收体，对可行的波导加工工艺和石墨烯转移方法进行研究和探索；（3）探索石墨烯实现超快被动锁模的物理机理；（4）理论分析和实验研究光纤色散、非线性以及石墨烯饱和吸收体其内部载流子动态、饱和吸收强度、调制深度等对锁模光纤激光器的输出脉冲宽度、脉冲幅值、脉冲的重复频率以及稳定性等方面的影响。最终获得稳定性较高的超短激光脉冲输出。

石墨烯具有优异的电学性能和非线性光学特性，在物理、化学等很多领域都有着重要的应用价值。目前，对石墨烯在超快光子学，尤其在超快被动锁模中的应用研究已成为备受瞩目的国际前沿和热点。本项目针对超快被动锁模过程中输出脉冲不稳定与热损伤阈值过低的问题，已开展了以下理论与实验方面的研究：（1）以提高石墨烯饱和吸收体性能为目标，提出了两种高热损耗阈值的石墨烯饱和吸收体，一种是基于微纳光纤的石墨烯饱和吸收体，另一种是基于大模场光纤的石墨烯饱和吸收体；（2）并制备了两种石墨烯饱和吸收体，对其可行性加工工艺和石墨烯转移方法及性能进行了理论与实验的研究和探索；（3）理论上探索了石墨烯实现超快被动锁模的物理机理，并实现了超快高功率的被动锁模与调Q，其单脉冲能量可达157.9 nJ，锁模脉宽可达883.9  fs，频率可从几KHz 到几十MHz 领域；（4）通过对输入石墨烯饱和吸收体偏振光的调控获得了脉宽可调谐的锁模脉冲输出，其脉宽调谐范围为：∼9.24 到 ∼2.32 ps.；（5）开展了关于石墨烯-微纳光纤光电子器件方面的理论研究工作，为未来新型石墨烯光电子器件的研制打下基础。该部分的研究工作为石墨烯锁模光纤激光器的研究提供非常有价值的参考，对未来将石墨烯锁模光纤激光器用于超连续谱产生领域和THz信号产生领域有着非常重要的价值。