title: Photoelectron angular distributions from above threshold ionization of hydrogen atoms in strong laser fields.
abstract: We apply a scattering theory of nonperturbative quantum electrodynamics to study the photoelectron angular distributions (PADs) of a hydrogen atom irradiated by linearly polarized laser light. The calculated PADs show main lobes and jetlike structure. Previous experimental studies reveal that in a set of above-threshold-ionization peaks when the absorbed-photon number increases by one, the jet number also increases by one. Our study confirms this experimental observation. Our calculations further predict that in some cases three more jets may appear with just one-more-photon absorption. With consideration of laser-frequency change, one less jet may also appear with one-more-photon absorption. The jetlike structure of PADs is due to the maxima of generalized phased Bessel functions, not an indication of the quantum number of photoelectron angular momentum states.
authors.affiliation: State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China.
authors.forename: Lihua
authors.initials: L
authors.lastname: Bai
authors.forename: Jingtao
authors.initials: J
authors.lastname: Zhang
authors.forename: Zhizhan
authors.initials: Z
authors.lastname: Xu
authors.forename: Dong-Sheng
authors.initials: DS
authors.lastname: Guo