Multistate non-Hermitian Floquet dynamics in short laser pulses

A time-dependent non-Hermitian close-coupling method is developed for describing the interplay of decaying atomic dressed states in short laser pulses. This interplay accounts for a variety of phenomena. It is shown, in particular, that the probability that the atom is excited off-resonance is modulated by Stueckelberg oscillations, that the ionization yield may be reduced by dynamical coupling with a resonant and rapidly decaying dressed state, and that adiabatic stabilization of circular states subsists down to very short pulse durations.