激光二极管抽运的全固态激光器中,除了激光介质的温度分布和热透镜效应以外,抽运、冷却结构对获得高光束质量、高功率激光输出至关重要。基于热传导方程,在相同的抽运功率和传导冷却边界条件下,对单侧面抽运锯齿形(zigzag)板条、单侧面键合锯齿形板条、部分抽运板条三种不同抽运结构的温度分布、热致应力、温度导致的折射率变化进行了详细的分析,并通过光线追迹方法,比较了光束在锯齿形面内和垂直于锯齿形面内的光程差,由光程差曲线分析了激光束的热透镜效应。对三种抽运结构的端面温度、端面变形和端面变形导致的光程差也进行了对比分析。结果表明,三种抽运结构在锯齿形面内的光束均表现为发散特性,在垂直于锯齿形面内的光束表现为热聚焦效应,温度导致的热聚焦特性相差不是很大。而在消除端面效应方面,键合激光板条具有明显优势。最后,提出了热透镜效应的补偿方法。

Pump and cooling scheme play an essential role in getting high bright and high-average-power output for diode pumped solid-state lasers besides the temperature distribution and thermal lens effects. Base on heat conduction equations, under the condition of conductively cooling and the same pump power, temperature and thermal-induced stress and temperature induced refractive index are analyzed in detail in one-side pump zigzag slab, one-side pump diffusion bonding zigzag slab, partially pumped slab configurations. Using ray tracing method, the OPD (optical path difference) is compared in zigzag and perpendicular zigzag plane, and the thermal lens effect is analyzed with the OPD curves. The end temperature, end deformation, end OPD are also analyzed in contrast. It is shown that the beams are diverging in zigzag plane while they are focusing in perpendicular zigzag plane, and the diffusion bonding slab can eliminate end effect in evidence. At last, the compensation method of the thermal-lens effect is also proposed.