论文标题
强圆极化激光场中氢原子的低洼圆形状态的电离和激发
Ionization and excitation of low-lying circular states of the hydrogen atom in strong circularly polarized laser fields
论文作者
论文摘要
我们最初在六个圆形结合状态之一中对氢原子进行了从头算的计算，其主量子数n = 2、3和4，这是由短的圆形偏振激光脉冲辐照的400 nm。该场沿平行于原子角动量的Z分量平行的方向传播。我们研究原子以电离或处于某种结合（激发）状态或在激光脉冲结束后保持初始状态的概率。在大多数情况下，我们发现在具有不同磁量子数迹象的状态下，原子的电离概率有明显差异。通常电子（相对于激光场）比相反的等效物更快地电离。我们发现在n = 2和其他n（3或4）的初始状态的激发行为（作为峰值激光强度的函数）上的重要差异。对于较高的n，激发总是比电离弱，并且启动了更高的强度。对于n = 2，由于单光子吸收的概率很大，加上许多结合状态的种群，其主量子数n从3到几十个，因此强烈的激发出现在强电离之前。提出了对激发过程的准确分析。
We perform ab initio calculations for the hydrogen atom initially in one of the six circular bound states with the principal quantum numbers n = 2, 3 and 4, irradiated by a short circularly polarized laser pulse of 400 nm. The field propagates in the direction parallel to the z-component of the angular momentum of the atom. We investigate probabilities for the atom to ionize or to get on some bound (excited) state or to remain in the initial state after the end of the laser pulse. In most cases, we find pronounced differences in ionization probabilities for atoms in states having different signs of magnetic quantum number. Usually electrons corotating (with respect to the laser field) ionize faster than their counter-rotating equivalents. We have found important difference in the behavior of the excitation (as a function of the peak laser intensity) for initial states with n = 2 and other n (3 or 4). For higher n the excitation is always weaker than the ionization and starts for higher intensities. For n = 2 the strong excitation appears before strong ionization due to large probability of one-photon absorption combined with population of many bound states having principal quantum numbers n from 3 up to several dozen. Quite accurate analysis of the excitation process is presented.
