FOCUS Center, University of Michigan, Ann Arbor, Michigan 48109, USA.
Phys Rev Lett. 2010 Jun 4;104(22):220404. doi: 10.1103/PhysRevLett.104.220404. Epub 2010 Jun 1.
The scheme of a simultaneous multiple pulse focusing on one spot naturally arises from the structural features of projected new laser systems, such as the Extreme Light Infrastructure (ELI) and High Power laser Energy Research (HiPER). It is shown that the multiple pulse configuration is beneficial for observing e+ e- pair production from a vacuum under the action of sufficiently strong electromagnetic fields. The field of focused pulses is described using a realistic three-dimensional model based on an exact solution of the Maxwell equations. The e+ e- pair production threshold in terms of electromagnetic field energy can be substantially lowered if, instead of one or even two colliding pulses, multiple pulses are focused on one spot. The multiple pulse interaction geometry gives rise to subwavelength field features in the focal region. These features result in the production of extremely short e+ e- bunches.
一种针对单个点的同步多脉冲聚焦方案自然源于所提出的新型激光系统的结构特点，例如极端光基础设施（ELI）和高功率激光能量研究（HiPER）。结果表明，在足够强的电磁场作用下，多脉冲配置有利于观察真空中的 e+ e- 对产生。使用基于麦克斯韦方程组精确解的现实三维模型来描述聚焦脉冲的场。如果不是一个或甚至两个碰撞脉冲，而是多个脉冲聚焦在一个点上，则可以大大降低电磁场所需的 e+ e- 对产生阈值。多脉冲相互作用几何形状在焦点区域产生亚波长场特征。这些特征导致产生极短的 e+ e- 束。
