Spectroscopy of Atoms in a Strong Laser Field: New Method to Sensing Ac Stark Effect, Multiphoton Resonances Parameters and Ionization Cross-Sections

Abstract

The new consistent approach to atom in a strong realistic laser field, based on the relativistic energy formalism (S-matrix adiabatic formalism), relativistic Dirac equation Green function method and relativistic many-body perturbation theory with the Dirac-Kohn-Sham zeroth approximation, is applied to studying the resonant multiphoton resonances shifts and widths and ionization cross-sections. An approach to treating the multiphoton atomic processes is outlined on example of H, Cs, Kr,Mg etc. Analysis shows that the shift and width of the multi-photon resonance line for the interaction "atom-multimode laser pulse" is greater than the corresponding shift and width for a case of the "atom-single-mode pulse" (the Lorenz pulse model) interaction. From the physical point of view it is naturally provided by action of the photon-correlation effects and influence of the laser pulse multi-modity.