Department of Physics and Astronomy, University College London, Gower Street, London, WC1E 6BT, United Kingdom.
Joint Laboratory for Attosecond Science, University of Ottawa and National Research Council, 100 Sussex Drive, Ottawa, Ontario, K1A 0R6, Canada.
Sci Rep. 2017 Aug 8;7(1):7488. doi: 10.1038/s41598-017-07635-5.
A three-dimensional semiclassical model is used to study double ionization of Ar when driven by a near-infrared and near-single-cycle laser pulse for intensities ranging from 0.85 × 10 W/cm to 5 × 10 W/cm. Asymmetry parameters, distributions of the sum of the two electron momentum components along the direction of the polarization of the laser field and correlated electron momenta are computed as a function of the intensity and of the carrier envelope phase. A very good agreement is found with recently obtained results in kinematically complete experiments employing near-single-cycle laser pulses. Moreover, the contribution of the direct and delayed pathways of double ionization is investigated for the above observables. Finally, an experimentally obtained anti-correlation momentum pattern at higher intensities is reproduced with the three-dimensional semiclassical model and shown to be due to a transition from strong to soft recollisions with increasing intensity.
采用三维半经典模型研究了近红外和近单周期激光脉冲驱动下 Ar 的双电离，激光强度范围为 0.85×10¹⁰ W/cm² 至 5×10¹⁰ W/cm²。作为函数，计算了沿激光场偏振方向的两个电子动量分量之和以及相关电子动量的不对称参数和分布，强度和载波包络相位。与最近在使用近单周期激光脉冲的运动学完全实验中获得的结果非常吻合。此外，还研究了上述可观测量的双电离直接和延迟途径的贡献。最后，使用三维半经典模型再现了在更高强度下实验获得的反相关动量模式，并表明这是由于随着强度的增加从强到软再碰撞的转变。
