Abstract In this paper, we proposed the diameter-selected single-walled carbon nanotubes (SWCNTs) via the simple liquid phase separation for the pulsed 2 μm laser operation as the saturable absorber (SA). The nonlinear absorption properties of the prepared SWCNTs based SA at 2 μm were investigated. The modulation depth and the saturation intensity were 8% and 6.5 kW/cm2, respectively. By employing the diameter-specified SWCNTs SA, a stable passively Q-switched Tm:YLF laser was demonstrated at 2 μm for the first time. The maximum repetition rate of 35.9 kHz and the shortest pulse duration of 920 ns were achieved with the output coupler of T = 3%. The experiment results indicated that the diameter selection of SWCNTs could be a promising method to improve the Q-switching characteristics.

中文翻译：

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直径选择的单壁碳纳米管用于 2 μm 的无源 Q 开关操作

摘要 在本文中，我们通过简单的液相分离提出了直径选择的单壁碳纳米管 (SWCNTs) 作为可饱和吸收体 (SA)，用于脉冲 2 μm 激光操作。研究了制备的基于单壁碳纳米管的 SA 在 2 μm 处的非线性吸收特性。调制深度和饱和强度分别为 8% 和 6.5 kW/cm2。通过使用指定直径的 SWCNT SA，首次在 2 μm 处展示了稳定的被动调 Q Tm:YLF 激光器。使用 T = 3% 的输出耦合器实现了 35.9 kHz 的最大重复率和 920 ns 的最短脉冲持续时间。实验结果表明，单壁碳纳米管的直径选择可能是改善调Q特性的一种很有前景的方法。