Dual-scale turbulence in filamenting laser beams at high average power

TL;DR

This study explores the complex turbulence behaviors in high-power laser filaments, revealing how different turbulence sources operate on separate scales and affect beam stability.

Contribution

It provides new insights into the dual-scale turbulence phenomena in high-power laser filaments and their impact on beam stabilization.

Findings

Externally-imposed and self-generated turbulences act on different temporal and spatial scales.

Self-induced turbulence occurs on a 0.5 s scale, while external turbulence acts on a millisecond scale.

Decoupling of turbulence effects prevents stabilization of the laser beam.

Abstract

We investigate the self-induced turbulence of high repetition rate laser filaments over a wide range of average powers (1 mW to 100 W) and its sensitivity to external atmospheric turbulence. Although both externally-imposed and self-generated turbulences can have comparable magnitudes, they act on different temporal and spatial scales. While the former drives the shot-to-shot motion at the millisecond time scale, the latter acts on the 0.5 s scale. As a consequence, their effects are decoupled, preventing beam stabilization by the thermally-induced low-density channel produced by the laser filaments.