Liu Yuchun, Kang Panqiang, Li Enhao, Peng Yujie, Wang Jing, Yao Weichao, Leng Yuxin, Xu Zhizhan
Opt Express. 2025 Jul 14;33(14):29197-29210. doi: 10.1364/OE.567416.
We demonstrated a high-power, high-efficiency 2-μm Ho:YLF laser and investigated the repetition-rate division phenomenon in high-repetition-rate Q-switched mode of operation. The Ho:YLF laser produced 135 W of output power with an optical conversion efficiency of 68.3% in CW regime and over 55 W of average power in Q-switched regime, which, to the best of our knowledge, represent the highest power values achieved for both CW and Q-switched regimes of Ho:YLF lasers. Notably, a regular repetition-rate division phenomenon was observed when operating at high repetition rate of 10-30 kHz, i.e., the pulse repetition frequency shows an integer division of the set frequency, which is attributed to the insufficient energy storage during individual Q-switched cycles. To elucidate the underlying dynamics, we proposed a Q-switched laser model based on quasi-three-level rate equations, specifically tailored to the Ho:YLF gain medium. Theoretical analysis demonstrates that increasing the pump intensity is an effective approach to overcome the frequency division phenomenon. This study could provide practical design guidelines for achieving stable pulsed outputs in high-repetition-rate quasi-three-level Q-switched lasers.
我们展示了一种高功率、高效率的2微米Ho:YLF激光器，并研究了其在高重复频率调Q工作模式下的重复频率分频现象。该Ho:YLF激光器在连续波（CW）模式下产生了135瓦的输出功率，光转换效率为68.3%，在调Q模式下平均功率超过55瓦，据我们所知，这代表了Ho:YLF激光器在连续波和调Q模式下所实现的最高功率值。值得注意的是，当在10 - 30千赫兹的高重复频率下运行时，观察到了一种规则的重复频率分频现象，即脉冲重复频率呈现出设定频率的整数分频，这归因于各个调Q周期内储能不足。为了阐明其潜在动力学，我们基于准三能级速率方程提出了一个调Q激光模型，该模型专门针对Ho:YLF增益介质进行了定制。理论分析表明，增加泵浦强度是克服分频现象的有效方法。这项研究可为在高重复频率准三能级调Q激光器中实现稳定脉冲输出提供实用的设计指导。
