氦原子非次序双电离对正交双色场强度比的依赖关系

利用经典系综模型研究了正交双色场中氦原子非次序双电离对双色场强度比的依赖关系.研究表明, 该依赖关系与双色场相对相位φ 有关. φ =0.25π 时,沿长波长激光偏振方向的相关动量谱随强度比的增大从相关模式转变为反相关模式. φ =0.35π, 0.45π 时,相关动量主要分布在第一和第三象限,相关模式几乎不随强度比的变化而变化.对双电离轨迹碰撞时间、碰撞角、碰撞动量的向后分析可以解释上述结果,并显示了正交双色场对非次序双电离中碰撞时间、碰撞角的控制作用.

Dependence of nonsequential double ionization of He on intensity ratio of orthogonal two-color field

Using classical ensemble model,the dependence of nonsequential double ionization of He on intensity ratio of orthogonal two-color field is investigated.It is shown that this dependence is related to the relative phase(φ) of two-color pulse.Whenφ= 0.25π,with intensity ratio increasing,correlated momentum distribution along the polarization of long wavelength field changes from correlation to anticorrelation pattern;whenφ= 0.35π,0.45π,correlated momenta are mainly distributed in the first and third quadrants,correlation pattern is nearly unchanged with the variation of intensity ratio.Back analyses of recollision time,recollision angle,recollision momentum of double ionization trajectories are responsible for the above results,and reveal the control of recollision time and the recollision angle in NSDI by orthogonally polarized two-color field.