在惯性约束聚变(ICF)激光驱动器中，片状放大器系统为装置提供超过99%的能量，是装置最重要的系统之一。大口径高通量验证实验平台(ITB)装置是我国为开展ICF研究而研制的激光装置，单束输出能量达到19.6 kJ(脉宽5 ns，中心波长1053 nm)。介绍了大口径N31 钕玻璃片在ITB 装置400 mm 单口径片状放大器系统中应用的增益特性。实验结果表明，采用尺寸为810 mm×460 mm×40 mm、Nd³⁺离子浓度为3.5×10²⁰ cm^-3的N31钕玻璃片，结合装置片状放大器系统放电回路参数与抽运腔结构参数优化，输出小信号增益系数达到5.28%/cm，增益损耗比为15∶1；360 mm 激光光束口径范围内增益均匀性(最大值/平均值)达到1.063∶1。

As one of the most important element in the inertial confinement fusion (ICF) laser device, slab amplifier provides over 99% energy. The integration-test-bed (ITB) is established for the research of ICF in China with the single- beam output energy up to 19.6 kJ (pulse width 5 ns, center wavelength 1053 nm). This paper studies characteristics of N31 neodymium glass in 400 mm aperture, single-segment amplifying system of ITB. The N31 glasses with size of 810 mm×460 mm×40 mm and Nd³⁺ ion concentration of 3.5×10²⁰ cm^-3 are used. Results show that combined with the optimized parameters of discharge circuit for slab amplifier and structure of pump cavity, the small signal gain coefficient reaches 5.28% cm^-1, the gain ratio is 15:1 , and the gain uniformity is 1.063∶1 (maximum/ average) within 360 mm beam diameter.