在使用高功率激光装置进行物理实验时,高精度时间同步的时标系统是实现物理过程精确诊断的必要条件。为了满足物理实验需求,该系统采用任意波形发生器输出信号时分复用结合高速电光调制的技术方案,同源产生了主激光、时标光、电时标和高精度触发信号等多路信号。时标系统共可输出532,355,266 nm三种波长共10路梳状时标光信号及8路梳状电时标信号、两路快前沿高幅值触发信号。时标信号与主激光时间同步抖动峰峰值达到12.80 ps,梳状时标光信号脉冲周期峰值抖动为6.40 ps,接近目前采用的测量系统极限。完成了时标系统在高功率激光装置中的应用演示,满足了诊断设备应用要求;对条纹相机不同扫程进行时间基准标定实验,可有效校准相机大扫程的时间误差。

振镜作为一种二维扫描器件, 可以实现光学元件不同位置处表面情况在CCD相机上的成像, 利用振镜扫描方式无需移动待检测光学元件和成像系统即可完成大口径光学元件表面损伤的扫描检测,提出了一种基于振镜扫描方式的大口径光学元件表面损伤检测方法。利用该方法对光学元件表面损伤点检测进行了验证实验, 通过在元件表面设置基准点, 利用振镜扫描步数及图像处理技术确定损伤点位置及尺寸, 并与光学显微镜观察到的损伤情况进行对比, 结果显示利用振镜扫描方法对元件表面损伤点位置及尺寸的检测结果与光学显微镜检测结果偏差较小。该检测系统分辨率可达到(2.08±0.015) μm/pixel, 检测范围大于2.5 cm, 水平方向和竖直方向位置坐标检测准确度分别为3.76%和1.37%, 损伤点尺寸检测准确度为6.19%, 能够实现较大尺寸光学元件表面损伤点的高准确性检测。

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.

In high power laser beam parameters measurement, attenuation scheme with high rate is key to far-field measurement. The far-field optical measurement system was analyzed and diameter of 95% encircled energy was used as important evaluation criterion of far-field measurement system. Measurement error of far-field optical measurement system and effect of attenuation with high rate on far-field measurement results were analyzed. Principle of attenuation scheme with high rate was established. By changing parameters of high attenuation rate in condition of single parallel plate, a pair of parallel plates and a pair of wedge flaps by Virtual Lab, influence of attenuation on the far-field measurement system was simulated and analyzed deeply. According to measurement system for f=3 000 mm and F=10, best attenuation scheme with high rate is designed. Diameter of 95% encircled energy of far-field image is 45.5 ?滋m, or 3.54 times of diffraction limitation.

In high power laser beam parameters measurement, attenuation scheme with high rate is key to far-field measurement. The far-field optical measurement system was analyzed and diameter of 95% encircled energy was used as important evaluation criterion of far-field measurement system. Measurement error of far-field optical measurement system and effect of attenuation with high rate on far-field measurement results were analyzed. Principle of attenuation scheme with high rate was established. By changing parameters of high attenuation rate in condition of single parallel plate, a pair of parallel plates and a pair of wedge flaps by Virtual Lab, influence of attenuation on the far-field measurement system was simulated and analyzed deeply. According to measurement system for f=3 000 mm and F=10, best attenuation scheme with high rate is designed. Diameter of 95% encircled energy of far-field image is 45.5 ?滋m, or 3.54 times of diffraction limitation.

Based on the mass fraction of 65% deuterated DKDP crystals, the fourth harmonic conversion of 1053 nm laser is realized under the condition of noncritical phase matching (NCPM). The experimentally measured crystal temperature is 29.4 ℃ and the acceptance angle width of the crystals under the NCPM condition is around 55 mrad. Effects of the deuterated amount and the temperature of the DKDP crystals in the process of NCPM on the fourth harmonic conversion are theoretically analyzed. The relationship between the deuterated amount and temperature and the changing of the fourth harmonic conversion efficiency versus the double frequency light intensity are numerically simulated. These results provide a theoretical basis for the application of fourth harmonic laser in the high power laser system.

The noncritically phase-matched (NCPM) fourth-harmonic generation (FHG) with partially deuterated dihydrogen phosphate (KD*P) crystal at an Nd:glass laser radiation wavelength of 1053.1 nm has been confirmed. NCPM FHG has been achieved in 70% and 65% deuterated KD*P crystal at the temperature of 17.7°C and 29.3°C, respectively. The angular acceptance of 70% and 65% deuterated KD*P crystals fixed at their NCPM temperature were measured, which were 53 and 55 mrad, respectively. The application of the NCPM FHG in a high-power laser facility for inertial confinement fusion is also discussed. Based on the theoretical analysis, the NCPM KD*P can be placed after the focus lens; thus, the laser-induced damage of a fused-silica lens at ultraviolet can be avoided.

利用质量分数为65%的掺氘DKDP晶体实现了1053 nm激光在非临界相位匹配(NCPM)条件下的四次谐波转换，实验测得NCPM条件下晶体温度为29.4 ℃、晶体接收角宽约为55 mrad。理论分析了NCPM过程中DKDP晶体掺氘量和温度对四次谐波转换的影响，数值模拟了四次谐波转换过程中晶体掺氘量和温度的关系以及四倍频转换效率随倍频光强的变化，这些结果为四倍频光在高功率激光系统中的应用提供了理论依据。