Theoretical Study of a Dual-Wavelength Collaboratively Pumping Ho:YLF Pulse Laser at 3.9 μm

单波长888 nm激光直接泵浦Ho掺杂氟化物晶体产生的3.9 μm激光存在自终止现象，为消除该自终止效应，本文提出了888 nm和2.1 μm双波长协同泵浦的技术方案，以实现3.9 μm脉冲激光的高效输出。以Ho:YLF晶体为增益介质，建立了888 nm和2.1 μm双波长协同泵浦3.9 μm激光器速率方程理论模型，数值模拟了各能级粒子数密度和腔内光子数密度随时间的变化；优化了输出镜透过率、晶体长度、掺杂浓度等参数；并分析了888 nm连续泵浦光功率、2.1 μm脉冲泵浦光参数以及泵浦光斑半径对3.9 μm脉冲激光器输出性能的影响。本论文的研究结果为实现3.9 μm脉冲激光的高效输出提供了理论指导。The self-termination effect exists in the 3.9 μm laser generated in Ho-doped fluoride crystals by the single-wavelength 888 nm laser pumping. To eliminate the self-termination effect and realize high-efficiency output of the 3.9 μm pulse laser, a novel scheme of 888 nm and 2.1 μm dual-wavelength collaboratively pumping is proposed. Using Ho:YLF crystal as the gain medium, a rate equation theoretical model for the 3.9 μm laser under dual-wavelength 888 nm and 2.1 μm collaboratively pumping is established. The temporal evolutions of population density at each energy level and the intracavity photon density are numerically simulated. Parameters including output mirror transmittance, crystal length, and doping concentration are optimized. Furthermore, the effects of 888 nm pump power, 2.1 μm pump pulse parameters, and pump beam radii on the output performance of the 3.9 μm pulse laser are analyzed. The research results of this paper provide a theoretical guidance for realizing efficient 3.9 μm pulse laser output.