Huang Cheng, Zhong Mingmin, Wu Zhengmao
Opt Express. 2018 Oct 1;26(20):26045-26056. doi: 10.1364/OE.26.026045.
Nonsequential double ionization of helium in counter-rotating two-color circularly polarized laser fields is investigated with a three-dimensional classical ensemble model. At moderate intensity, the momentum distribution of the two electrons shows a maximum in the middle of each side of the triangle of the negative vector potential. At high intensity, the momentum distribution exhibits a double-triangle structure, which is attributed to the different values of the laser intensity where the two electrons are released after recollision. At low intensity, the momentum distribution shows a shift deviating from the middle of the side of the triangle of the negative vector potential. This is because the first electrons are emitted within a narrow time window after the field maximum. In addition, at low intensity, double-recollision events and NSDI originating from doubly excited states induced by recollision are prevalent.
利用三维经典系综模型研究了在反向旋转双色圆偏振激光场中氦原子的非顺序双电离。在中等强度下，两个电子的动量分布在负矢量势三角形每一侧的中间出现最大值。在高强度下，动量分布呈现双三角形结构，这归因于两个电子在再碰撞后释放时激光强度的不同值。在低强度下，动量分布显示出偏离负矢量势三角形边中间的偏移。这是因为第一个电子在电场最大值之后的狭窄时间窗口内发射。此外，在低强度下，双再碰撞事件以及由再碰撞诱导的双激发态产生的非顺序双电离很普遍。
