Accurately and efficiently predicting the fundamental-frequency temporal shape of broadband long-pulsed lasers is very important in research on the properties of high-power laser amplifiers. In this study, we first propose that analytic electric polarization in the temporal domain is applied to broadband long-pulsed pulse amplification. We first verify the accuracy of this algorithm in the dozens of picoseconds range and the results are consistent with Miro software. Then we simulate the broadband long-pulsed amplification. The simulation results indicate that the front edge of the output pulse is more enlarged than the end edge owing to saturation and that the gain narrowing induces severe amplitude modulation. Analytic electric polarization in the temporal domain is effective and precise for investigating the broadband pulse amplification in the time scale from dozens of picoseconds to nanoseconds, and the computation time can be decreased by at least 4 orders of magnitude.

Accurately and efficiently predicting the fundamental-frequency temporal shape of broadband long-pulsed lasers is very important in research on the properties of high-power laser amplifiers. In this study, we first propose that analytic electric polarization in the temporal domain is applied to broadband long-pulsed pulse amplification. We first verify the accuracy of this algorithm in the dozens of picoseconds range and the results are consistent with Miro software. Then we simulate the broadband long-pulsed amplification. The simulation results indicate that the front edge of the output pulse is more enlarged than the end edge owing to saturation and that the gain narrowing induces severe amplitude modulation. Analytic electric polarization in the temporal domain is effective and precise for investigating the broadband pulse amplification in the time scale from dozens of picoseconds to nanoseconds, and the computation time can be decreased by at least 4 orders of magnitude.

Aiming at the disadvantage that the traditional measurement technique is sensitive to the incident direction of incident light, a beam-split technique of high power laser multi-parameter measurement based on integrating sphere is proposed. Numerical analysis and simulation about attenuation rate, time waveform of emergent light, and time waveform recovery of incident light are carried out by Monte-Carlo method, which validate the feasibility that the integrating sphere can be used as beam-splitter in laser measurement system. The energy and time waveform of nanosecond laser is measured based on integrating sphere. The theoretical analysis matches well with the experiment result. Experiment and simulation results show that spectrum parameter, energy parameter and time parameter of incident light can be recovered by measuring the parameters of the emergent light, when the light-split technique is used in laser parameters measurement. The proposed technique can conquer the disadvantage that the incident direction of incident light has great influence on the parameters of the emergent light in traditional technique. The proposed technical proposal possesses small volume and is easy to integrate, which can be used in modular design of multiple beam high power laser parameters measurement system.

针对传统测量技术对入射光入射方向敏感的缺点，提出了一种基于积分球的高功率激光多参数测量的分光技术。采用蒙特卡罗法对衰减率、出射光时间波形特性、入射光时间波形恢复这三个方面进行了数值分析和仿真，验证了积分球作为激光测量系统中的分光元件的可行性。利用积分球对纳秒激光的能量和时间波形进行测量，实验结果与理论分析相符。实验与仿真均表明在激光参数测量中采用该分光技术，通过测量出射光各项参数可以恢复入射光的光谱参数、能量参数、时间参数，克服传统技术中入射光的入射方向对于出射光的各项参数有较大影响的问题。该技术方案占用空间小、易于集成，可用于多路高功率激光参数测量系统的模块化设计。

Damage experiments are conducted by irradiating fused silica with the multiple wavelength laser near field. The multiple wavelength laser consists of 1053、 527、 351 nm laser. It designs a definition of damage threshold based on laser near-field irradiation and extracts damage areas from damage images by the marker-based watershed algorithm with gray control. The initial damage threshold is defined as the fluence of critical site between damage region and no damage region, which is calculated by comparing the damage image with the multiple wavelength laser near field. The research shows that the damage of fused silica is induced by the three wavelength lasers. The 351 nm laser plays a leading role. The initial damage threshold is 8.22 J/cm2. With multiple irradiation of fused silica in multiple wavelength laser, the damage growth of exit surface is exponential, and the coefficient of damage growth is 0.59.

自动准直系统是将采集的图像进行特定算法处理获取光束的位置信息, 驱动电机调整光斑到指定的位置, 其中图像质量对光束定位的精确性影响很大, 为尽量避免受严重噪音和光束畸变影响的图像进入图像处理流程而产生准直结果的错误判断, 保证自动准直系统图像处理结果的精确性, 试图提供一种较为简单的判断依据, 采用基于Monte-Carlo模拟方法, 建立了远场准直过程中三种主要噪音的干扰评估模型, 以测量不确定度作为定量判断处理图像与否的特征参数, 将该结果做成统计图表作为判断依据。结果表明, 在设定合理测量不确定度阈值的情况下, 该特征参数能够较好地排除不良图像, 从而提高准直结果的可信度。

在复合波长(波长分别为1053、527、351 nm)情况下，利用激光近场对熔石英样品进行损伤实验。设计了一种基于激光近场辐照的损伤阈值定义方法，并利用带有灰度抑制的分水岭标记算法对损伤图像进行损伤区域提取，通过对比损伤图像与相应光束近场能量分布，计算出损伤区域与非损伤区域临界处的光能量密度，即为熔石英样品的损伤阈值。实验结果表明，复合波长激光诱导熔石英损伤是3种波长激光共同作用的结果，但351 nm激光对损伤起主要作用，初始损伤阈值为8.22 J/cm2；在复合波长激光多次辐照样品的情况下，熔石英样品后表面的损伤成指数形式增长，损伤增长系数为0.59。

为了准确测量皮秒量级超短脉冲的信噪比，扩大测量仪器的可测动态范围，针对高功率超短激光脉冲在相关过程中产生参量荧光的问题,研制了一台重复频率扫描测量的三阶相关仪，并在皮秒域短脉冲光学参量啁啾脉冲放大(OPCPA)抽运源上开展了测量技术研究。研究实验表明，通过采用大角度非共线匹配方式，消除了参量荧光对测量过程的影响，进而通过结构优化降低了背景噪声的影响，使可测动态范围达到107左右。由于互相关技术的非对称性，该测量系统可同时提供时间波形的分析功能。测量结果显示，激光脉冲前沿与双曲正割(sech)型曲线比较吻合，而脉冲后沿与高斯型曲线吻合得比较好。

设计了一台双光路自相关的透反射率测量系统，实验测试了3种不同形态激光作光源时，系统的单点透反射率重复性精度，验证了光源的功率和偏振稳定性对此系统的影响较小。在验证性分析的基础上完善了系统的稳定性，并对系统精度进行校准。实验结果显示，在置信度为95%时，系统的重复不确定性能稳定在0.04%左右，满足大口径低透射率、低反射率光学元件均匀性测量的精度要求，为此类仪器设计提供了参数选择依据。