An analysis on the efficient laser photoionization of atoms

The basic characteristics of the two-step three-level laser photoionization of atoms with statistical broadening were analyzed by using the Block equation. It followed from the numerical results that, in most practical cases, the minimum laser fluence in terms of the efficiency of ionization is obtained when the Rabi frequency of the first excitation step is larger than that of the second excitation step. The minimum fluence is dependent on the ionization probability and the degree of broadening, while there is little dependence on the interaction time. (author)