在量子电动力学框架下,采用全量子非微扰散射理论,研究了超快强激光场中离子的光离解。 发现在保持周期数与载波-包络相位不变时,对相同的阈上离解峰,当用频率为γ 倍,强度为γ3倍的激光激发结合能为γ 倍的离子时,光电子的角分布不变, γ 为任意正实数。这一研究验证了周期量级超短激光脉冲中光电离的标度规律。

In accordance with nonperturbative quantum scattering theory, we investigate photoelectron angular distributions (PADs) from above-threshold detachment (ATD) of negative ions irradiated by circularly polarized few-cycle laser fields. Electrons ejected on the polarization plane demonstrate distinct anisotropies in angular distributions which distinctly vary with the carrier-envelope (CE) phase. The anisotropy is caused by interference between transition channels; it also depends strongly on laser frequency, pulse duration, and kinetic energy of photoelectrons. Optimal emission of photoelectrons, which varies with CE phase, makes it possible to control photoelectron motion.

Photoelectron angular distributions (PADs) from two-photon ionization of atoms in linearly polarized strong laser fields are obtained in accordance with the nonperturbative quantum scattering theory. We also study the influence of laser wavelength on PADs. For two-photon ionization very close to the ionization threshold, most of the ionized electrons are vertically ejected to the laser polarization. PADs from two-photon ionization of atoms are determined by the second order generalized phased Bessel function at which the ponderomotive parameter plays a key role. In terms of dependence of PADs on laser wavelength, corresponding variations for the ponderomotive parameter are demonstrated.