A theoretical model of laser ionization of alkali vapors based on resonance saturation

Abstract

We have developed a theoretical model of the ionization that results from extended laser saturation of an atomic resonance transition within a dense alkali vapor. Although this model includes all of the essential collisional-radiative interactions, nevertheless, it leads to relatively simple analytical relations that predict the ionization time history to within 20% of that calculated by our extensive laser ionization based on resonance saturation (LIBORS) computer code in the case of sodium. When allowance is made for the temporal and spatial nature of a realistic laser pulse, the apparent ionization time has been shown to be approximately double that of the value predicted on the basis of a steplike, flat laser pulse.