研究了薄片激光器中晶体与热沉的封装技术和核心技术，采用薄片晶体与金刚石热沉的光胶工艺，自主设计并研制了5 mm口径的YAG/Yb∶YAG复合薄片激光模块，分析了该薄片激光模块的多通泵浦系统，建立了晶体热效应数值仿真模型，实验测量了在2.2 kW/cm²泵浦功率密度、940 nm泵浦波长下薄片晶体的热焦距为445.6 mm；采用基于光胶工艺封装的薄片激光模块搭建连续激光器，在70 W泵浦功率下获得了18.75 W功率的基横模输出，斜率效率和光光转换效率分别为36.59%和26.79%。

薄片激光器可以实现高峰值功率、高平均功率、高光束质量的激光输出，是高重复频率皮秒泵浦源的关键技术之一。基于Yb∶YAG单薄片激光模块设计并搭建了再生放大系统，连续泵浦下获得了平均功率为40.9 W、重复频率为1 kHz、脉冲宽度为3.4 ns的激光输出，水平方向上的光束质量因子（Mx2）和竖直方向上的光束质量因子（My2）分别为1.12和1.10。基于腔内光束指向主动控制技术，2 h输出的平均功率稳定性峰谷（PV）值和均方根（RMS）值分别为6.42%和0.56%。在600 μs脉冲泵浦情形下，光光效率达16.1%。在10 kHz重复频率下，获得了53.3 W的高平均功率的激光输出，Mx2和My2分别为1.07和1.06。

采用光强度调制鉴相方案,使用直接数字频率合成器(DDS)和激光驱动器产生频率稳定的调制激光,注入待测光路,在待测光路后进行光电转换和放大,引入参考本振信号作为混频器相位参考信号,利用混频器测量待测光路信号与参考本振信号的相位差,获得光路延时信息。主要特点如下:提出了在本振信号链路三段移相的差分式检测方法,优化了鉴相点,提高了测量精度;采用单段短时两相位点测量模式,有效降低了光源功率波动、光路中光强波动、光电探测及放大电路增益波动、温度变化导致相位差漂移等带来的测量误差;在每个相位点多次测量采样,根据测量的平均值计算相位差,推导时间差。详细分析了测量电压和被测时延之间的函数关系,分析了影响测量精度的因素,构建验证系统,完成了实验验证。实验结果表明:本方案在4 ns的时延内的测量精度可达1 ps,大幅提升了现有高功率激光装置的同步测量精度。

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。

搭建了一台中等重复频率、高峰值功率的Nd∶YAG激光器。激光器主要包括三部分：单纵模全光纤种子源、LD抽运的Nd∶YAG再生放大器和氙灯抽运的Nd∶YAG功率放大器。该系统获得了平均功率为12 W、重复频率为10 Hz、单脉冲能量为1.2 J、脉冲宽度为3 ns的激光输出, 工作波长为1064 nm, 输出光束口径为10 mm, 95%的能量在600 μrad范围内, 近场光强近平顶分布, 近场光强调制度小于1.2, 时间波形近似方波, 能量稳定性均方根值小于1.4%。

理论分析了基于边缘加热条件下气冷钕玻璃放大器的热致波前畸变, 模拟计算了不同加热温度下钕玻璃片的温度分布和热波前畸变分布, 并进行了实验验证。结果表明, 数值模拟与实验结果能较好地吻合, 在产热率为0.6 W/cm3时, 钕玻璃片产生的热波前畸变随着边缘温度的增加而减小, 而当边缘温度达到90 ℃时, 热波前畸变开始出现反转, 随温度增加而增加。合理设计边缘加热结构和优化加热温度, 能有效抑制气冷钕玻璃放大器的热波前畸变。

The development of the optically addressed spatial light modulator (OASLM) was reported. Its structure and working principle was introduced in detail. Meanwhile, the photosensitive response curve, static wave-front distortion and temporal waveform distortion was investigated in detail in the process of experiment. Besides, OASLM was successfully demonstrated in the online experiment. The results show that OASLM not only has the ability to achieve the desired transmittance distribution, but also has no additional effect on the high-power laser system. Finally, the shaping effect of spatial filter in the laser system was analyzed. The result shows that the size of spatial filter was also an important factor which determined the shaping precision when this device was used in high power laser systems.

Aiming at morphology of laser induced damage mitigation pit on the rear surface of 3ω silica optical component, the mitigated area and its downstream intensity distributions with different morphologies are simulated by finite-difference time-domain method (FDTD) and Rayleigh-Sommerfeld (R-S) diffraction integral method, respectively. The results show that when the angle between the tangent line of endpoints on the section contour of the pit and incident light is over 70°, the maximum intensity inside the mitigated optics is less than 1.66, and mitigation effect is better than that of other angles. The maximum downstream intensities of a pit in shape of parabolic surface, cone and truncated cone are all less than 1.46 with an angle of 70° and a width of 200 μm. But when the width of pit increases to 1 mm, for instance, the maximum downstream intensity is as high as 9.31 and area with high intensity covers a long range. Thus, taking the difficulty of laser machining technology into account, a conical pit with an angle larger than 70° is the first choice for the damage mitigation on the rear surface of silica optical component.