Generation of high power spatially-structured laser pulses via forward Raman amplification in plasma

TL;DR

This paper presents a plasma-based forward Raman amplification method capable of generating high-power, spatially-structured laser pulses with petawatt-level peak power, high efficiency, and broad applicability, advancing high-field physics and ultrafast science.

Contribution

The authors develop a universal plasma-based amplification scheme that significantly enhances the power of structured laser beams using forward Raman amplification, enabling petawatt-level outputs with compact setup.

Findings

Achieved 10,000 to 100,000-fold intensity amplification of structured laser seeds.

Generated high-power structured laser pulses with petawatt-level peak power.

Suppressed plasma instabilities due to short interaction times and plasma conditions.

Abstract

Spatially-structured light with tunable intensity, wavelength, and spatiotemporal profiles has demonstrated significant potentials for fundamental and applied science, including the ultrafast and high-field physics. Nevertheless, the generation or amplification of such light towards extremely high power remains challenging due to the limitations of conventional gain media. Building upon our recently proposed forward Raman amplification (FRA) mechanism [Lei et al., Phys. Rev. Lett. 134, 255001 (2025)], here we develop a universal plasma-based amplification scheme that is capable of generating high-power structured laser beams, including vortex, Bessel, and Airy beams. Through theoretical modeling and multi-dimensional particle-in-cell simulations, we demonstrate that a near-infrared structured seed laser with an initial intensity of 1e12 W/cm2 can achieve 1e4~1e5-fold intensity amplification via FRA, and subsequently be self-compressed to sub-cycle duration with petawatt-level peak power. Benefiting from its exceptionally high amplification growth rate, the FRA process requires only femtosecond-scale interaction time and submillimeter propagation distance in plasma, effectively suppressing concomitant plasma instabilities. The high output intensity 1e17 W/cm2, compactness (<500 um), high temporal contrast, universal applicability to diverse structured beams, and relatively easy implementation with the co-propagating configuration combine to make the FRA a disruptive approach to the generation of petawatt-class spatially-structured light, enabling unprecedented applications in high-field physics and ultrafast science.