Self-focusing and self-compression of intense pulses via ionization-induced spatiotemporal reshaping

TL;DR

This paper explores how intense laser pulses can self-focus and self-compress in helium gas via ionization-induced reshaping, revealing a new regime of pulse propagation that enhances laser intensity without traditional optics.

Contribution

It introduces a theoretical investigation of ionization-driven self-focusing and self-compression in intense laser pulses, highlighting a novel propagation regime.

Findings

Pulse undergoes self-focusing and self-compression due to ionization.

Results show a significant increase in laser intensity through this process.

Spatiotemporal frequency variation mediates the reshaping mechanism.

Abstract

Ionization is a fundamental process in intense laser-matter interactions, and is known to cause plasma defocusing and intensity clamping. Here, we investigate theoretically the propagation dynamics of an intense laser pulse in a helium gas jet in the ionization saturation regime, and we find that the pulse undergoes self-focusing and self-compression through ionization-induced reshaping, resulting in a manyfold increase in the laser intensity. This unconventional behavior is associated with the spatiotemporal frequency variation mediated by ionization and spatiotempral coupling. Our results illustrate a new regime of pulse propagation and open up an optics-less approach for raising the laser intensity.