Relationship of self-focusing to spatial instability modes

Abstract

The spatial distribution of focal spots formed when laser beams self‐focus in materials is shown to originate from the growth of certain instability modes. These modes are determined by a simple mathematical relationship derived from instability theory, which has been verified experimentally. Because of these instabilities, the threshold power for self‐focusing is inversely proportional to the self‐focusing length for high‐power laser beams.