精细结构混合速率对激光二极管抽运碱金属蒸气激光器性能的影响

Influence of Fine Structure Mixing Rate on Laser Diode Pumped Alkali Laser

以速率方程模型为基础研究了精细结构混合速率对激光二极管连续端面抽运碱金属蒸气激光器性能的影响,结果表明,对碱金属蒸气激光器P1/2和P3/2抽运能级的粒子数分布不能采用热平衡假设的方法处理,需要采用双向精细结构混合速率对其弛豫过程进行描述;当精细结构混合速率远远大于自发辐射速率和电子态猝灭速率时对激光器阈值的影响可以忽略;对抽运光的有效吸收不仅需要抽运谱宽与原子吸收谱宽相匹配,还需要足够的精细结构混合速率以克服吸收饱和效应;实际中可通过优化激光模体积和温度在较低的精细结构混合速率下实现较高的光-光转换效率。

Influence of the fine structure mixing rate on the CW end laser diode pumped alkali laser（DPAL） is studied based on the rate equation theory,result shows that the relaxation of the P1/2 and P3/2 energy levels should be described by the upward and downward fine structure mixing rates rather than the thermal equilibrium hypothesis.The influence of fine structure mixing rate on laser threshold can be neglected when it is very large comparing to the spontaneous emission and electronic quenching rates.Not only the match of the pump and atomic absorption width but also sufficient fine structure mixing rate to avoid the absorption saturation is needed for the effective absorption of the pump power.The laser medium length and the temperature can be optimized to achieve high optical-optical efficiency even at low fine structure mixing rate.