寄生振荡的存在使得放大器在信号光到达之前消耗了大量的反转粒子数,降低了放大器的激光增益和储能效率,严重地影响了激光放大器的性能,尤其对高功率激光放大器。在理论分析和实验研究的基础上,以Nd∶YAG晶体板条为例,用8条半导体激光阵列对晶体进行双侧抽运,研究了高功率激光放大器的寄生振荡现象,分析了板条晶体寄生振荡产生的原因,并详细比较了晶体在不同的抽运功率和表面处理下的放大效果,得到了2倍的单程放大,当输入能量为140 mJ时,获得了278 mJ的激光输出。

Existence of parasitic oscillation makes the amplifier consume lots of inversed population before the arrival of signal pulse, which reduces peak gain and storage efficiency and influence amplification performance greatly, especially for high-power amplifiers. By pumping Nd∶YAG slab with 8 laser diode arrays, parasitic oscillation in high-power amplifier was studied both theoretically and experimentally. The parasitic oscillations in the slab with different surfaces treatment were compared. When the pump energy was 1.28 J and the input pulse energy was 140 mJ, the single-pass amplification of β=2 and the output pulse energy of 278 mJ was obtained.