论文标题
焦点对极端激光强度的隧道离子化探针效率的影响
Focal-shape effects on the efficiency of the tunnel-ionization probe for extreme laser intensities
论文作者
论文摘要
我们研究了重点关注最近讨论的方案潜力的激光[M.F. ciappina {\ em et al}，物理。 Rev. A 99，043405（2019）;拉斯。物理。 Lett。 17，025301（2020）]用于原位确定多折叠激光设施传递的电磁辐射的超高强度。在激光束的焦点中，使用两个模型强度分布，我们展示了在来自原子的多个顺序隧穿过程中产生的高电荷离子的产量，取决于这些分布的形状。我们的发现得出的结论是，当只有在接近强度最大的点的一小部分激光焦点中，或通过确定点的点相等，就可以在接近阈值的峰值中准确提取峰值激光强度。我们表明，对于气体目标的实际参数，在阈值方面的焦点中心部分产生的离子数应该足以进行具有高度敏感的飞行时间探测器的可靠测量。尽管相交点的位置通常取决于焦点的形状，但它们可用于在一定间隔内定位峰强度值。除了此分析外，我们还讨论了该方法与最近提出的直接测量极端激光强度的方法相比。
We examine the effect of laser focusing on the potential of a recently discussed scheme [M.F. Ciappina {\em et al}, Phys. Rev. A 99, 043405 (2019); Las. Phys. Lett. 17, 025301 (2020)] for in situ determination of ultra-high intensities of electromagnetic radiation delivered by multi-petawatt laser facilities. Using two model intensity distributions in the focus of a laser beam, we show how the resulting yields of highly charged ions generated in the process of multiple sequential tunneling of electrons from atoms, depend on the shape of these distributions. Our findings lead to the conclusion that an accurate extraction of the peak laser intensity can be made either in the near-threshold regime when the production of the highest charge state happens only in a small part of the laser focus close to the point where the intensity is maximal, or through the determination of the points where the ion yields of close charges become equal. We show that, for realistic parameters of the gas target, the number of ions generated in the central part of the focus in the threshold regime should be sufficient for a reliable measurement with highly sensitive time-of-flight detectors. Although positions of the intersection points generally depend on the focal shape, they can be used to localize the peak intensity value in a certain interval. Additionally to this analysis, we discuss the method in comparison to other recently proposed approaches for direct measurement of extreme laser intensities.
