Key points are not available for this paper at this time.
Close to an atomic resonance, the dependence of the real part of the susceptibility on power level (i.e., saturation effects) can be sizeable and therefore lead to self-trapping or self-focusing. It is shown here under what conditions this effect can occur. Order of magnitude estimates are given for the intensity dependent index change and the diameter of the trapped beam for some laser materials.
Javan et al. (Thu,) studied this question.