Gauge independent theory applied to a model of atomic ionization by an intense laser pulse

Abstract

An explicitly gauge invariant strong field theory is introduced and tested using a model laser-atom interaction. The theory relies on a power series in the target potential. Transitions amplitudes are obtained by using a corresponding series in the momentum space wave function. We demonstrate that this approach is explicitly gauge invariant to all orders. A well know 1D delta function potential model is used to test the convergence of the series in the evaluation of total ionization probabilities and ionization spectra. Actually, the convergence is verified when both, the perturbation as well as the order of the expansion, are increased. © 2011 EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.