论文标题
超短循环激光场中的原子光电离动力学
Atomic photoionization dynamics in ultrashort cycloidal laser fields
论文作者
论文摘要
我们介绍了由二维原子模型中的超快多光子电离动力学的数值模拟，该模型由共同和反射的圆形极化单色和双裂载体载体相（CEP）稳定的Ultrashort激光脉冲序列驱动。考虑到由于CEP波动而引起的阶段变化和GOUY阶段，我们的结果准确地繁殖了最近测量的光电子动量分布[Pengel等，Phys。莱特牧师。 118，053003（2017），物理。 Rev. A 96，043426（2017）; Kerbstadt等人，Nat。通讯。 10，685（2019），Adv。物理。 X 4，1672583（2019）]。计算坐标和动量空间中复合价值电子波函数的时间演变，以研究结合状态和涡流形成动力学。非变化方位角概率电流密度证明了具有奇数旋转对称性的电子波包的涡流性质。它们的角动量期望值假设半数为3.5（旋转）和0.5（反向旋转）。对波函数的了解使我们能够分析光电离动力学并验证先前实验研究中提出的物理图片。作为前景，我们研究了电子涡流如何随着激光强度的增加从多光子到隧道状态。
We present numerical simulations of ultrafast multiphoton ionization dynamics in a two-dimensional atomic model driven by co- and counterrotating circularly polarized single-color and bichromatic carrier envelope phase (CEP) stable ultrashort laser pulse sequences. Taking into account phase variations due to CEP fluctuations and the Gouy phase, our results accurately reproduce recently measured photoelectron momentum distributions [Pengel et al., Phys. Rev. Lett. 118, 053003 (2017), Phys. Rev. A 96, 043426 (2017); Kerbstadt et al., Nat. Comm. 10, 685 (2019), Adv. Phys. X 4, 1672583 (2019)]. The time evolution of the complex-valued electron wave function in coordinate and momentum space is calculated to study the bound state- and the vortex formation dynamics. The non-vanishing azimuthal probability current density proves the vortex nature of electron wave packets with odd-numbered rotational symmetry. Their angular momentum expectation value assumes half-integer values of 3.5 (corotating) and 0.5 (counterrotating). Knowledge of the wave function allows us to analyze the photoionization dynamics and to validate the physical pictures proposed in previous experimental studies. As an outlook, we investigate how electron vortices develop from the multiphoton- to the tunnel regime with increasing laser intensity.
