Physical insights on the CW on‐resonance whole beam absorptive and off‐resonant dispersive small‐scale self‐focusing in propagation of laser beams in saturable absorbers*

Analytical and numerical calculations to elucidate the propagation of very intense CW laser beams in saturable absorbers are presented. The beam profile can be either (i) smooth thus experiencing whole beam collapse for the case of on‐resonance, or (ii) corrugated with small‐scale ripples which leads to off‐resonant small‐scale self‐focusing.