Here we report on the exfoliation of graphene by using femtosecond pulsed laser with the highly oriented pyrolytic graphite (HOPG) immersed in water. The size of the graphene flakes was demonstrated to be well regulated by controlling the peak-power density of the femtosecond laser irradiation on the HOPG. The transmission electron microscopy (TEM) and Raman spectroscopy were used to identify the morphology and crystalline phase of the graphene. As an application, the few-layers-graphene absorber with a modulation depth of 0.5% was used in a passive Q-switched Nd: YVO4 laser. A Q-switched nanosecond pulse train with the maximum pulse energy of 262.35 nJ and the narrowest pulse duration of 131.6 ns was obtained.

中文翻译：

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飞秒脉冲激光制备石墨烯及其在被动调Q固态激光器中作为可饱和吸收体的应用

在这里，我们报告了通过使用飞秒脉冲激光将高度取向的热解石墨 (HOPG) 浸入水中来剥离石墨烯。通过控制飞秒激光照射在 HOPG 上的峰值功率密度，证明了石墨烯薄片的尺寸可以得到很好的调节。透射电子显微镜（TEM）和拉曼光谱用于鉴定石墨烯的形态和晶相。作为一种应用，调制深度为 0.5% 的少层石墨烯吸收体用于被动调 Q Nd:YVO4 激光器。获得了最大脉冲能量为 262.35 nJ 和最窄脉冲持续时间为 131.6 ns 的调 Q 纳秒脉冲序列。