端面抽运板条放大器抽运均匀性和热效应模拟

Numerical simulation of pumping uniformity and thermal effects of LD end-pumped slab amplifier

为了使激光二极管抽运的全固态激光器能够得到高光束质量、高功率的激光输出,对激光介质的温度分布和热透镜效应的研究很重要。利用ZEMAX软件的非序列模块,根据光束追迹的方法模拟了端面抽运结构下,高功率二极管抽运激光放大器的抽运光在增益介质中的光场分布情况。结果表明,此抽运方式下光场分布均匀。将激光介质中吸收的抽运光体功率密度分布结果代入LAS-CAD软件,计算出在种子光未注入和注入情况下,抽运功率为2400W时,增益介质最大温差分别为68℃,54.7℃以及最大热应力分别为90N/mm^2,67N/mm^2,因此当抽运功率小于2400W,运转的全过程对于激光增益介质是没有威胁的。该模拟结果对于高功率二极管抽运板条激光放大器的设计具有一定参考价值。

In order to obtain high bright and high-average-power output of diode pumped solid-state laser, the temperature distribution in the laser medium and thermal lens effects, essential for improving the laser performance, were analyzed. With the help of ZEMAX software, the distribution of pump light in gain material was analyzed when end-pumped by high power LD. Simulation results showed that the optical field distribution was uniform with that in end-pumped structure. Then applying the pump power density in gain material to LASC-AD software, under the condition of the amplifier before and after being seeded, with the pump power of 2400W, the maximum temperature differences were 68℃ and 54. 7℃ respectively, maximum thermal stress were 90N/mm^2 and 67N/mm^2 respectively. Therefore, when the pumping power was lower than 2400W, there was no threat for the laser gain medium under the entire operation of the amplifier. The simulation results have a certain reference value for the design of high-power diode-pumped slab amplifier.