摘要： 石墨烯中超快载流子弛豫时间和宽波段非线性饱和吸收特性，使得它在超快光电领域的应用中成为理想材料。然而，石墨烯的形态、层数等因素不同，其非线性光学特性也将随之变化。为使石墨烯材料更好应用在超快光电领域，本文从形态、层数和激发光强几个方面，系统研究了石墨烯的超快载流子动力学，发现形态和层数对石墨动力学过程没有影响，而激发光强可以改变载流子浓度，从而改变了石墨烯的超快弛豫过程。接着，利用开孔Z扫描测量技术，研究了石墨烯从可见光到中红外波段下的非线性吸收特性，发现其具有超宽波段可饱和吸收特性，有潜力应用在超快光纤激光器和开关中。
关键词： 石墨烯；超快载流子动力学；非线性吸收

JIANG Yaqin^*

（  Troops no.95857；  ）

Abstract： Graphene hold great promise in ultrafast photonic applications owing to their unique properties, such as ultrafast carrier relaxation and broadband nonlinear saturable absorbers. However, the shape and the layers of graphene are different, and the nonlinear optical properties will be changed. In order to make graphene material better application in ultrafast optoelectronic field, the paper makes systematical study of the ultrafast carrier dynamics in graphene from the shape, layers and excitation intensity. It is found that the shape and number of layers did not affect the dynamics process, but the excitation intensity can change carrier concentration, thus change the ultrafast relaxation process of graphene. Then we studied the nonlinear absorption through open aperture Z-scan system from the visible to the mid-infrared broadband frequency range. This finding suggests the saturable absorption property of graphene with possible applications as a passive Q-switcher and mode-locker in ultrafast lasers and ultrafast optical switches.
Keywords： graphene; ultrafast carrier dynamics; nonlinear absorption

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