Theory of two-color pump-probe determination of ionization dynamics

We show, through numerical simulations, that it is, in principle, possible to follow in time the structure and the population dynamics of an atomic system “dressed” by a strong time-varying laser field. The proposed time-resolved spectroscopy scheme exploits the properties of the currently developed sources of coherent extreme ultraviolet radiations, generated via high-order harmonic conversion. With pulse durations within the femtosecond range, it is possible to conceive two-color pump-probe schemes that would help to shed light on issues currently under discussion about the dynamics of strong-field photoionization.