神光Ⅱ大型固体高功率激光装置是我国激光驱动器发展历史的里程碑, 其成功研制使我国高功率固体激光工程与技术、聚变物理与基础物理研究实现了全面且本质的跨越式发展。简要概述了神光Ⅱ激光装置研制中创新发展的大量工程方案与技术手段, 举例介绍了神光Ⅱ激光装置在近20年来的高质量运行中取得的众多有国际影响力的研究成果。经多方支持和多年持续发展, 已经形成数万焦耳级纳秒激光装置、皮秒拍瓦以及飞秒拍瓦激光装置等, 这些装置是我国惯性约束核聚变、强场物理、高能量密度物理等研究领域中重要的物理实验核心平台之一。

测试了应用于神光Ⅱ系列装置93片N31型钕玻璃的小信号增益系数。结果表明，Nd2O3质量分数为2.2%的钕玻璃平均小信号增益系数为0.0387 cm-1，Nd2O3质量分数为3.0%的钕玻璃平均小信号增益系数为0.0416 cm-1，两种浓度的钕玻璃不同样品间小信号增益系数的起伏范围分别为0.86%和0.76%。根据所测定的增益值，表明N31型钕玻璃的增益起伏符合神光Ⅱ系列装置要求，为实现该装置中每一路增益性能的平衡提供了有力保障，也为今后对更大尺寸钕玻璃增益性质的控制提供了经验。

A theoretical calculation is presented for third-harmonic generation in KDP crystal for type Ⅱ- type Ⅱ polarization-mismatch scheme by using the four-stepped Runge-Kutta method. For the “Shenguang Ⅱ” frequency tripling system, the doubling angle θd and the tripling angle θt are located at optimized situation, by changing detuned values of the polarization angle θp, the corresponding changes of pulse shape properties was gotten. The results show that when the polarization angle θp is located at optimized situation, the full width at half maximum (FWHM) τ is minimum and the pulse shape rises fastest. Increasing the θp from optimized situation causes the τ widens faster and the pulse shape rises slower than decreasing the θp from optimized situation. In the experiment, by changing the polarization angle θp, the pulse shapes consistency of the “Shenguang Ⅱ” eight frequency tripling beams has been accomplished. This work offers a method for adjusting crystals and actualizing power balance.

使用四阶龙格-库塔算法数值求解Ⅱ类-Ⅱ类偏振失配方案的三倍频稳态耦合波方程组。针对“神光Ⅱ”激光驱动器的三倍频系统，在二倍频匹配角θd和三倍频匹配角θt均处于最佳匹配情况下，以1°为单位改变偏振分配角θp的偏离量，得到对应的三倍频波形特性的变化。研究表明，偏振分配角θp处于最佳理论匹配位时，对应的三倍频波形半峰全宽最窄，且波形上升沿抬起也最快; θp从最佳匹配位增加比从最佳匹配位减小对应的半峰全宽变宽更快，对应的上升沿抬起更慢。根据所得理论结果，在实验中调节偏振分配角θp,达到了改变三倍频输出波形特性，进而实现八路三倍频波形一致的目的。该研究结果对于更快地实现激光驱动器装置的功率平衡有一定的应用价值。

This paper discusses a method of characterizing the gain of the laser pulse amplifier using its gain fluence curves and studies gain fluence Curves of a single amplifier．These help US to understand the characteristics of the amplifier and provide a powerful tool for the investigation of the power balance．

For precision SG-Ⅱ power balance, there must have same output energy and output pulse waveform in the 8 beams, it means that the gain and transmissivity in every amplifier chain are same. But the gain abilities of the same type amplifiers in 8 beams are different for needing of daily operation. It was a first time that small signal gain of different amplifiers in SG-Ⅱ were measured online by using a small energy measurement system which has superior 1% precision. The small signal gain values of 40 and 70 rod amplifiers, 100 slab amplifiers and 200 double slab amplifiers are got in the regular working voltages. The differences of the same type amplifiers are quantized and that provides valuable experimental data to power balance in SG-Ⅱ precision.

Power balance between laser beams is important for high-power laser system. This paper uses a calculation method as an exact solution for laser amplification to simulate the output pulse shape of “Shenguang Ⅱ" laser facility. The results are preferable,as compared with the results of the experiments.