Observation of Laser Power Amplification in a Self-Injecting Laser Wakefield Accelerator

TL;DR

This paper demonstrates laser power amplification in a laser wakefield accelerator, showing the laser pulse's peak power increases significantly during plasma propagation, linked to electron injection and acceleration.

Contribution

It provides experimental evidence of laser power amplification in a self-injecting wakefield accelerator and models the process involving redshift and group delay dispersion.

Findings

Peak laser power increased from 187 TW to 318 TW

Power amplification correlates with electron injection and acceleration

Model includes localized redshift and group delay dispersion

Abstract

We report on the depletion and power amplification of the driving laser pulse in a strongly-driven laser wakefield accelerator. Simultaneous measurement of the transmitted pulse energy and temporal shape indicate an increase in peak power from $187 \pm 11$ TW to a maximum of $318 \pm 12$ TW after 13 mm of propagation in plasma density of $0.9 \times 10^{18}$ cm$^{-3}$. The power amplification is correlated with the injection and acceleration of electrons in the nonlinear wakefield. This process is modeled by including localized redshift and subsequent group delay dispersion at the laser pulse front.