Laser-Driven Recollisions under the Coulomb Barrier.
Laser-Driven Recollisions under the Coulomb Barrier.
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DOI：
10.1103/physrevlett.117.243003
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发表时间：
2016-08
影响因子：
8.6
通讯作者：
T. Keil;S. Popruzhenko;Dieter Bauer
中科院分区：
文献类型：
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作者：
T. Keil;S. Popruzhenko;Dieter Bauer
从含时薛定谔方程的从头算解得到的光电子能谱可能与强场近似(SFA)的预言截然不同，不仅在低能下，而且在预计从直接电子到再散射电子的跃迁的动能的两倍左右。事实上，在这种情况下，与SFA相比，电离几率的相对提高可以是几个数量级。我们展示了对于哪些激光和目标参数发生了这样的增强，以及对于哪些SFA预测是定性良好的。考虑库仑势垒下的软再碰撞，从库仑修正作用的角度分析了在复时间平面中沿解析量子轨道的增强作用。这些在复杂的时间和空间中的再碰撞防止了分离成亚势垒运动，直到“隧道出口”和随后的经典动力学。相反，直到探测器的整个量子路径决定了电离概率。
Photoelectron spectra obtained from the ab initio solution of the time-dependent Schrödinger equation can be in striking disagreement with predictions by the strong-field approximation (SFA), not only at low energy but also around twice the ponderomotive energy where the transition from the direct to the rescattered electrons is expected. In fact, the relative enhancement of the ionization probability compared to the SFA in this regime can be several orders of magnitude. We show for which laser and target parameters such an enhancement occurs and for which the SFA prediction is qualitatively good. The enhancement is analyzed in terms of the Coulomb-corrected action along analytic quantum orbits in the complex-time plane, taking soft recollisions under the Coulomb barrier into account. These recollisions in complex time and space prevent a separation into sub-barrier motion up to the "tunnel exit" and subsequent classical dynamics. Instead, the entire quantum path up to the detector determines the ionization probability.