高功率片状放大器在线运行时氙灯辐照导致片腔内产生大量气溶胶，易引起钕玻璃污染，影响其使用寿命。采用洁净氮气吹扫恢复片腔内的洁净环境是片状放大器在线运行时的主要洁净手段。研究了氮气吹扫过程中片腔内涡流对洁净度的影响，结果显示涡流对气溶胶颗粒的禁锢作用会导致腔内气溶胶颗粒的大量残留，且无法通过延长吹扫时间或调整吹扫流速加以解决。针对这一问题，提出了间断多次氮气吹扫对腔内气溶胶进行循环稀释的在线洁净控制方法，该方法使腔内涡流经历不断破坏和重建过程，涡流场内滞留的气溶胶颗粒含量也得到不断稀释，从而大幅提高片腔洁净度。针对Φ130 mm单口径片状放大器进行了对比实验研究。采用间断吹扫法之后，腔内残留气溶胶颗粒为连续吹扫时的1/100，片腔洁净度在15 h的观测时间内始终保持在40级以内。该方法普适有效，为避免片状放大器钕玻璃气溶胶污染,增加其在线使用寿命提供了重要参考。

An all-fiber Faraday rotator isolation rate measurement system is designed and realized. The system has tremendous advantage for large aperture Faraday isolator on-line measurement due to its flexible alignment and more compaction. Employing the method of relative transmission measurement and transmissions contrasting between static and operating states, single-shot isolation-rate measurement is achieved. The available measurement range larger than 33 dB is demonstrated experimentally. And the potential to get measurement range larger than 50 dB by adjusting the coupling rate of the fiber couplers is affirmed. Measurement accuracy of 2.2%of PV value is achieved even while keeping the input pulse energy and polarization in random vibration, which illustrates that the influence of the input pulse energy and polarization vibration on the measurement accuracy is eliminated.

An all-fiber Faraday rotator isolation rate measurement system is designed and realized. The system has tremendous advantage for large aperture Faraday isolator on-line measurement due to its flexible alignment and more compaction. Employing the method of relative transmission measurement and transmissions contrasting between static and operating states, single-shot isolation-rate measurement is achieved. The available measurement range larger than 33 dB is demonstrated experimentally. And the potential to get measurement range larger than 50 dB by adjusting the coupling rate of the fiber couplers is affirmed. Measurement accuracy of 2.2%of PV value is achieved even while keeping the input pulse energy and polarization in random vibration, which illustrates that the influence of the input pulse energy and polarization vibration on the measurement accuracy is eliminated.

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.

Without discrete optical components influencing the fiber format, all-fiber mode-locked laser has tremendous potential practical applications due to its advantages of better stability, alignment free, and better compaction. All-fiber laser mode-locked by nonlinear polarization evolution (NPE) can obtain good performances in terms of pulse duration and spectrum. But the effective saturable absorption mirror can be overdriven at high peak power, which leads to multiple pulses, limiting the output pulse energy. And there is a trade-off between avoiding overdriving the NPE and ease of self-starting. In addition, the polarization of the pulse propagating in a long fiber is so sensitive to the environment vibration that it is difficult to implement a stable lone-time operation. All-fiber ring laser mode-locked by NPE alone is analyzed and realized. The simulation results show that even a polarization vibration of /38 can break the mode-locking completely. Experimentally, after carefully adjusting, singlepulse mode-locking is achieved with the spectrum centered at 1053.4 nm and a maximum pulse energy of 82 pJ. But the output parameters change continually during operating. After 60 min, the mode-locking is broken. The conclusion is obtained that instability and unreliability of self-starting are inevitable for such a laser. Here, we show significant improvements of the pulse energy, operating stability, and self-starting reliability from an all-fiber Yb-doped mode-locked fiber laser. The laser is mode-locked by NPE combined with chirped pulse spectral filtering (CPSF). In order to easily self-start and stabilize mode locking, a spectral filter is employed in the all-normal group velocity dispersion NPE cavity to provide additional amplitude modulation. Combined effects of NPE and CPSF result in desirable pulse output, desirable operating stability, and reliable self-starting simultaneously. Stable mode-locking centered at 1053 nm is achieved with a 3 dB spectral bandwidth of 9.1 nm and pulse duration of 17.8 ps. The average output power is 66.9 mW at a repetition rate of 15.2 MHz, corresponding to a pulse energy of 4.25 nJ. Especially, high operating stability and easily one-button self-starting are achieved simultaneously. The fluctuations of output parameters including pulse energy, pulse duration, and spectrum are within 0.3% during 150-min operation. Self-starting reliability is tested. The testing time lasts two weeks. During the two weeks, the laser is turned off and turned on 48 times by using a power supplying button, without any adjustment. And the re-turned on intervals change randomly. Each time, the mode-locking can start itself. The repeatabilities of output parameters including pulse energy, pulse duration, and spectrum are within 0.55%.

报道了自研的光寻址空间光调制器的最新进展, 介绍了器件工作原理与结构, 并对其光敏响应特性曲线、静态位相波前畸变、透射时间波形畸变的离线测试结果进行了报道, 同时也利用该器件在高功率激光装置上进行了在线测试。结果表明, 该调制器可以根据需求实现所需的强度透过率分布, 而且对高功率激光系统没有引入附加的影响。最后, 结合该调制器的实际使用环境, 分析了激光系统空间滤波器对整形效果的影响, 说明在高功率激光系统中使用该调制器时, 空间滤波器尺寸也是决定光束整形精度的重要因素。

在神光II九路装置上，利用谱色散匀滑(SSD)技术结合分布式相位板(DPP)技术，研究了激光焦斑在一维、二维谱色散匀滑下的分布。结果表明，一维谱色散匀滑使焦斑的焦斑通量对比度由0.7634[均方根（RMS）]下降到0.3685（RMS），结合二维匀滑下降到0.2638（RMS）；并结合各种评价方法对焦斑进行分析。实验为谱色散匀滑技术在神光II在线应用提供了参考。

透镜列阵常被用于改善高功率激光装置均匀照明系统焦斑空间强度分布的均匀性。将模拟退火算法引入透镜列阵的优化设计中，通过改变列阵元的尺寸及其正负透镜属性，在保证焦斑能量利用率的同时把焦斑的不均匀度从经典设计下的0.2268降低到0.1202，大大改善了远场焦斑的空间均匀性，并通过对比传统设计和优化设计下焦斑的功率谱密度曲线，分析了不同的设计结构对焦斑形态的影响。

在惯性约束聚变中,辐照的均匀性直接影响到内爆实验的效果,通常结合各种空间、时间平滑技术提高光束的均匀性。光谱色散平滑技术正是一种常用的时间平滑技术,其核心是频谱展宽技术。为提高频谱展宽的效果,将单通的腔式调制器设计成双通调制器,以满足光谱色散平滑技术中频谱展宽的要求。理论上计算了双通调制器情况下的速度匹配条件,得到了一个清晰的表达式,同时在实验上验证了理论分析的正确性,以此验证了双通调制器的可行性。最后基于以上方案,进一步提出了改进成多通调制器的构想。

利用柯林斯(Collins)传输公式和将硬边光阑展开为有限个复高斯函数之和的方法,分析了在静态高功率激光器系统中选取不同尺寸的空间滤波器小孔对谱色散匀滑(SSD)效果的影响,并且通过K.R.Manes等提出的统计光学模型,给出了存在相位畸变和振幅调制时小孔选取的模拟计算方法。数值模拟表明,在神光Ⅱ第9路多功能激光器系统中,目前使用的空间滤波器小孔会使部分色散光束的光谱成分被阻断,使得焦斑通量对比度从无孔时的22％增大到36％,影响光SSD效果;分析给出了满足光SSD使用的空间滤波器的小孔尺寸。