Haynam C A, Wegner P J, Auerbach J M, Bowers M W, Dixit S N, Erbert G V, Heestand G M, Henesian M A, Hermann M R, Jancaitis K S, Manes K R, Marshall C D, Mehta N C, Menapace J, Moses E, Murray J R, Nostrand M C, Orth C D, Patterson R, Sacks R A, Shaw M J, Spaeth M, Sutton S B, Williams W H, Widmayer C C, White R K, Yang S T, Van Wonterghem B M
Lawrence Livermore National Laboratory, Livermore, CA 94551, USA.
Appl Opt. 2007 Jun 1;46(16):3276-303. doi: 10.1364/ao.46.003276.
The National Ignition Facility (NIF) is the world's largest laser system. It contains a 192 beam neodymium glass laser that is designed to deliver 1.8 MJ at 500 TW at 351 nm in order to achieve energy gain (ignition) in a deuterium-tritium nuclear fusion target. To meet this goal, laser design criteria include the ability to generate pulses of up to 1.8 MJ total energy, with peak power of 500 TW and temporal pulse shapes spanning 2 orders of magnitude at the third harmonic (351 nm or 3omega) of the laser wavelength. The focal-spot fluence distribution of these pulses is carefully controlled, through a combination of special optics in the 1omega (1053 nm) portion of the laser (continuous phase plates), smoothing by spectral dispersion, and the overlapping of multiple beams with orthogonal polarization (polarization smoothing). We report performance qualification tests of the first eight beams of the NIF laser. Measurements are reported at both 1omega and 3omega, both with and without focal-spot conditioning. When scaled to full 192 beam operation, these results demonstrate, to the best of our knowledge for the first time, that the NIF will meet its laser performance design criteria, and that the NIF can simultaneously meet the temporal pulse shaping, focal-spot conditioning, and peak power requirements for two candidate indirect drive ignition designs.
国家点火装置（NIF）是世界上最大的激光系统。它包含一个192束的钕玻璃激光器，其设计目的是在351纳米波长下以500太瓦的功率输出1.8兆焦耳的能量，以便在氘 - 氚核聚变靶中实现能量增益（点火）。为实现这一目标，激光设计标准包括能够产生总能量高达1.8兆焦耳的脉冲，峰值功率为500太瓦，并且在激光波长的三次谐波（351纳米或3ω）处时间脉冲形状跨越2个数量级。通过激光1ω（1053纳米）部分中的特殊光学元件（连续相位板）、光谱色散平滑以及多束具有正交偏振的光束重叠（偏振平滑）的组合，仔细控制这些脉冲的焦斑能量密度分布。我们报告了NIF激光器前八束光的性能鉴定测试。报告了在1ω和3ω处有和没有焦斑调节情况下的测量结果。按全192束运行进行缩放时，据我们所知，这些结果首次证明NIF将满足其激光性能设计标准，并且NIF能够同时满足两种候选间接驱动点火设计的时间脉冲整形、焦斑调节和峰值功率要求。
