基于空域评价和分布统计的高功率激光装置近场状态分析方法  

Near⁃Field Status Analysis Method for High⁃Power Laser Facility Based on Space Domain Evaluation and Distribution Statistics

作　　者：陈伟[1,2] 范薇 杨琳[1,3] Chen Wei;Fan Wei;Yang Lin(Joint Laboratory of High Power Laser and Physics,Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,Shanghai 201800,China;Center of Materials Science and Optoelectronics Engineering,University of Chinese Academy of Sciences,Beijing 100049,China;Collaborative Innovation Center of IFSA,Shanghai Jiao Tong University,Shanghai 200240,China)

机构地区：[1]中国科学院上海光学精密机械研究所高功率激光物理联合实验室,上海201800 [2]中国科学院大学材料科学与光电研究中心,北京100049 [3]上海交通大学IFSA协同创新中心,上海200240

出　　处：《中国激光》2024年第14期87-99,共13页Chinese Journal of Lasers

基　　金：中国科学院战略性先导科技专项(A类)(XDA25020303)。

摘　　要：惯性约束聚变高功率激光驱动器优质的近场分布是提升装置输出性能的关键。研究了高功率激光装置基频近场状态的分析方法,利用统计光学理论,获得了近场通量分布的概率密度函数及其近似表达式,近场的统计特性反映出其整体分布特征及其变化原因,由于信号通量和噪声通量可以用于描述理想的光束分布及扰动,近场分布信噪比能更显著地反映光束受扰动影响的程度;提出并验证了局部对比度和局部调制度的应用可行性,即能够定位近场异常区域并分析其状态演化;通过近场光束的通量统计研究了高通量点的演化过程,提供怀疑发生损伤的区域,并对高通量点与信噪比之间的指数模型提出了对比度的控制要求。研究结果为装置在高功率激光辐照下的安全运行提供了理论基础和实验支撑,提出了新的近场状态评估方法,对装置维护和运行策略调整起到一定的指导作用。Objective An inertial confinement fusion(ICF) high-power laser driver with a high-quality near-field distribution is key to enhancing the output performance of a facility. Meanwhile, a high-quality beam with a uniform intensity distribution is beneficial for the protection of the subsequent optics and reduces the operating costs of the facility. Furthermore, it can satisfy the long-term highfluence operation requirements of a system and improve the frequency-conversion efficiency and beam focus. Therefore, assessment methods should be used to evaluate the quality of near-field beams to provide early warning to operators. However, the current methods for evaluating near-field beam quality are incomplete and cannot analyze status changes and the details of near-field beam quality under the normal operating conditions of a facility. Additionally, the multiple outputs of high-power laser facilities place stringent requirements on real-time analysis;therefore, a multidirectional assessment of the facility operating status must be provided to the operators. This study may provide a theoretical basis and experimental support for the safe operation of the SG-II UP grade facility under high-load irradiation, thus facilitating timely maintenance and adjustments to the operating strategy.Methods Domain evaluation and distribution statistics were proposed to analyze the fundamental frequency near-field status of the SG-Ⅱ upgrade laser facility in our study. First, the probability density function of the near-field fluence distribution(Rician distribution) and its approximate expression(Gaussian distribution) were obtained using statistical optics theory, which was used to analyze the effects of high and low fluences in the near-field distribution on beam quality. We solved for the noise fluence, signal fluence, and near-field distribution signal to noise ratio, which were used to reflect the magnitude of and variation in random perturbations in the near-field distribution. Subsequently, local contrast and local modulation

关 键 词：高功率激光驱动器 近场光束质量 分布统计 空域评价 近场分布信噪比 

分 类 号：TN24[电子电信—物理电子学]