为探索同带泵浦掺杂Ho3+激光晶体1.2 μm波段红外激光输出, 采用掺杂浓度为1 at%的Ho3+: LLF激光晶体作为激光增益介质, 应用两种典型准三能级理论模型, 计算了Ho3+在5I6和5I8 能级间跃迁辐射1.19 μm激光的阈值功率, 分析了泵浦光和激光束腰半径、激光晶体长度、吸收损耗、腔镜反射率等参量与阈值功率的变化关系, 得出了吸收损耗是影响阈值功率最敏感因素的重要结论, 确定了泵浦阈值功率的范围, 为后续1.2 μm波段红外激光实验研究提供了可靠的理论参考数据.

The threshold power of 1.2 μm laser generated from the Ho3+: LLF crystal was discussed. Two typical quasi-three-level theoretical models were used to analyze the effectiveness of 1194 nm laser's threshold power in the in-band pumping source of 1.15 μm fiber laser with different parameters, such as the absorption coefficient of laser medium, the laser beam radius, the crystal length and reflectivity of the output mirror. It was found that the re-absorption loss was the most important factor leading to the different results for the two models, and the second model was close to the practice because of the narrow bandwidth pumping beam(<6 nm). The results provided reliable data of Ho3+-doped 1.2 μm solid-state laser systems for the design and experimental research in further.