Dependence on frequency of strong-field atomic stabilization

It is shown that strong-field atomic stabilization can occur at any frequency, that analytical methods exist that can describe all essential features of stabilization, that relativistic effects enhance the stabilization phenomenon, and that a simple physical picture exists that explains these properties. A necessary prelude is to show that the frequency properties of the three methods often conjoined by the KFR (Keldysh-Faisal-Reiss) label are quite different. Applicability of the SFA (Strong-Field Approximation) to stabilization at any frequency is shown, and verified by exhibiting close correspondence to numerical predictions by Popov et al. that also span both low and high frequencies.