Above-threshold detachment of negative ions by circularly polarized few-cycle laser fields

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.     

线偏振周期量级脉冲中H-强场光解离的不对称性

Photodetachment of H^- irradiated by linearly polarized few-cycle laser field is investigated by time-dependent Schr?dinger equation numerically. The photo-electron left-right asym-metry parameter as a function of carrier-envelop (CE) phase of few-cycle pulses is attained. We confirm the asymmetry of photoelectron distribution in H^- photodetachment and find that the maximal asymmetry parameter of H^- is equal to that of H atom under the same conditions but the corresponding CE phases are quite different. Thus a CE phase shift ap-pears. Compared to that of H atom and field free electron, the zero asymmetry CE phase shift is sensitively affected by Coulomb field. The Coulomb effect on the asymmetry of H^- photodetachment mainly behaves in the CE phase shift of H^- instead of the amplitude of asymmetry parameter curve.     

线偏振周期量级脉冲中H-强场光解离的不对称性

用数值求解含时薛定谔方程的方法研究了线偏振周期量级激光场中氢负离子光解离的不对称性．通过计算随载波-包络(CE)相位变化的光电子不对称参数,证实光电子分布的不对称性存在于氢负离子光解离过程中．在相同条件下,氢负离子最大不对称参数与氢原子的相等,而与之相应的CE相位却不相同,从而呈现出CE相位的移动．通过比较氢原子和无外场电子发现这种相位的移动敏锐受到库仑场的影响．进一步计算了在这些特殊CE相位上的瞬时电离率直观地呈现出周期量级脉冲光解离的不对称性.     

Photoelectron angular distributions from two-photon ionization of atoms near ionization threshold

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 twophoton 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.