Transition from plasma- to Kerr-driven laser filamentation

TL;DR

This paper investigates the transition between plasma-driven and Kerr-driven laser filamentation regimes, demonstrating that pulse duration determines whether plasma or higher-order Kerr effects dominate filament stabilization.

Contribution

It provides experimental and numerical evidence for the regime transition, highlighting the role of pulse duration in filamentation mechanisms.

Findings

Long pulses (1.2 ps) involve plasma in filamentation.

Short pulses (70 fs) show filamentation driven by higher-order Kerr effects.

Transition between regimes depends on pulse duration.

Abstract

While filaments are generally interpreted as a dynamic balance between Kerr focusing and plasma defocusing, the role of the higher-order Kerr effect (HOKE) is actively debated as a potentially dominant defocusing contribution to filament stabilization. In a pump-probe experiment supported by numerical simulations, we demonstrate the transition between two distinct filamentation regimes at 800\,nm. For long pulses (1.2 ps), the plasma substantially contributes to filamentation, while this contribution vanishes for short pulses (70 fs). These results confirm the occurrence, in adequate conditions, of filamentation driven by the HOKE rather than by plasma.