准三能级固体激光器中激光介质长度优化

Optimizing the Laser Medium Length in Quasi Three Level Solid State Lasers

为进一步提高激光二极管端面泵浦的准三能级激光器转化效率,基于速率方程理论,引入能量传输上转换效应和激发态吸收效应,对自吸收损耗进行研究。设计了平凹谐振腔,采用不同长度的Nd:GdVO4晶体作为激光介质进行实验验证。研究结果表明:自吸收损耗同激光介质长度呈正比关系,但随着泵浦功率增加而减弱。实验结果证明了最佳激光介质长度的存在,泵浦功率30 W以内,最佳激光介质长度在5~6.5mm范围内递增,且实验结果和理论计算结果相符合。

To raise the conversion efficiency of the diode-end-pumped quasi-three-level solid-state laser,a study was made of the reabsorbed loss on the basis of the rate equation and by introducing the energy transfer up-conversion effect and the excited state absorption effect.A plano-concave resonator was designed,and the Nd:GdVO4 crystals of different lengths were used as the laser medium.The results show that the reabsorbed loss is directly proportional to the laser medium length,but inversely to the pump power.Experimental results prove the existence of an optimum laser medium length.For the pump power within 30 W,the optimized medium length increases between 5 mm to 6.5 mm.The experimental results are in good agreement with the theoretical results.