Author Affiliations
Abstract
1 Key Laboratory of High Power Laser and Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai, China
2 Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, China
Frequency modulation (FM)-to-amplitude modulation (AM) conversion is an important factor that affects the time–power curve of inertial confinement fusion (ICF) high-power laser facilities. This conversion can impact uniform compression and increase the risk of damage to optics. However, the dispersive grating used in the smoothing by spectral dispersion technology will introduce a temporal delay and can spatially smooth the target. The combined effect of the dispersive grating and the focusing lens is equivalent to a Gaussian low-pass filter, which is equivalent to 8 GHz bandwidth and can reduce the intensity modulation on the target to below 5% with 0.3 nm @ 3 GHz + 20 GHz spectrum phase modulation. The results play an important role in the testing and evaluating of the FM-to-AM on the final optics and the target, which is beneficial for comprehensively evaluating the load capacity of the facility and isentropic compression experiment for ICF.
dispersion grating frequency modulation-to-amplitude modulation conversion high-power laser facility inertial confinement fusion phase modulation High Power Laser Science and Engineering
2024, 12(1): 010000e9
针对惯性约束聚变装置中多色光谱色散匀滑技术在集束中的运用, 提出了对电光调制器、色散光栅和连续相位板(CPP)等主要单元器件进行独立设计和优化的思路。基于这一思路, 分别模拟和分析了电光调制器、色散光栅和CPP等单元器件的参数对集束辐照特性的影响。提出了优化的多色光谱色散匀滑方案参数, 并仿真了束匀滑参数对激光束纵向成丝特性的影响。结果表明,通过优化不同子束的电光相位调制器和色散光栅参数,可以进一步改善靶面的辐照均匀性。当集束中各子束采用不同的CPPs时, 焦斑均匀性得到有效改善, 热斑比例明显降低。采用功率谱密度对激光束的光束质量进行分析, 结果表明多色光谱色散匀滑方案能有效降低峰值强度, 使光强分布更加均匀, 从而有利于抑制激光束成丝。
激光光学 多色 调制频率 色散光栅 连续相位板 均匀性
