Coulomb and polarization effects in laser-assisted XUV ionization

We consider spectra of one-photon ionization of an atom by an attosecond XUV pulse in the presence of an intense laser pulse, for different delays between the laser and the XUV pulses. Such a spectrogram, which is expected to record the instantaneous laser field, is distorted by the influence of the Coulomb atomic potential on the electron motion after XUV ionization and by the laser-induced polarization of the initially bound electron wave packet before XUV ionization. We analyse these distortions using consistently-derived Coulomb-corrected wavefunctions of the strongly-driven continuum electron. We demonstrate quantitative accuracy of these wavefunctions and of the corresponding photoelectron spectra. We then show how the Coulomb-corrected wavefunctions can be used to disentangle Coulomb and polarization effects in the spectrogram, opening the route to attosecond XUV dynamical imaging of the electronic wave packet undergoing strong-field distortion and ionization.NRC publication: Ye