Laser beam self-symmetrization in air in the multifilamentation regime

TL;DR

This paper demonstrates experimentally and numerically that focused laser beams undergoing multi-filamentation in air spontaneously self-symmetrize due to nonlinear Kerr effects, redistributing wave vectors symmetrically before focus.

Contribution

It provides the first combined experimental and numerical evidence of laser beam self-symmetrization in air during multi-filamentation, highlighting the role of Kerr-mediated nonlinear interactions.

Findings

Self-symmetrization occurs prior to focus in multi-filamentation.

Kerr effect mediates nonlinear interactions leading to symmetry.

Symmetric wave vector redistribution observed experimentally and numerically.

Abstract

We show experimental and numerical evidence of spontaneous self-symmetrization of focused laser beams experiencing multi-filamentation in air. The symmetrization effect is observed as the multiple filaments generated prior to focus approach the focal volume. This phenomenon is attributed to the nonlinear interactions amongst the different parts of the beam mediated by the optical Kerr effect, which leads to a symmetric redistribution of the wave vectors even when the beam consists of a bundle of many filaments.