RYDBERG ELECTRONS IN INTENSE FLUCTUATING LASER FIELDS

The influence of laser fluctuations on the optical excitation of Rydbe rg and continuum states close to a photoionization threshold is invest igated within the framework of the phase diffusion model. Theoretical methods are developed for solving the relevant master equation of the atomic density operator which is averaged over the laser fluctuations. In the long-time limit this laser-induced excitation process exhibits nonexponential decay. This nonexponential time dependence reflects th e fluctuation-induced diffusion of the Rydberg electron toward the ion ization threshold.