对亚纳秒脉宽激光脉冲进行了双通放大的实验研究。双通放大器增益介质掺杂原子数分数为1.0%，3 mm×120 mm的Nd:YAG棒。为了消除自激振荡和放大自发辐射(ASE)效应，Nd:YAG棒两端面采用1.5°倾角设计。为了获得较高的能量提取效率，通过选择合适的扩束镜倍率，保证主振荡器输出的种子激光光斑面积大约为晶体棒端面面积的80%。主振荡器输出的单脉冲能量为0.16 mJ，重复频率为5 Hz，脉冲宽度为0.964 ns，M2为1.5的种子激光，经过Nd:YAG双通放大后，得到了单脉冲能量88 mJ，脉宽0.975 ns，M2为1.7，不稳定度小于±3%，550倍的稳定高增益亚纳秒激光双通放大输出。

The experiment of sub-nanosecond pulse width Nd:YAG double-pass amplification is studied. Double pass amplifier gain medium is Nd:YAG rod with 3 mm×120 mm size and doping atomic fraction of 1.0%. The two end surfaces of Nd:YAG rod with an angle of 1.5° is designed to avoid self-oscillation and amplified spontaneous emission (ASE) effect. The beam expanding lens magnification is optimized appropriately, the seed laser spot area is selected about 80% of Nd:YAG rod surface area to obtain a higher efficiency. The master oscillator output laser with single pulse energy of 0.16 mJ, repetition frequency of 5 Hz, M2 of 1.5, and pulse width of 0.964 ns is obtained. The Nd:YAG double-pass amplifier output laser with single pulse energy of 88 mJ, M2 of 1.7, stability of ±3%, pulse width of 0.975 ns has been obtained and the total gain is 550.