Proof-of-principle experiment for nanoparticle-assisted laser wakefield acceleration

TL;DR

This paper demonstrates a pioneering experiment where nanoparticles generated by laser ablation are used to enhance laser wakefield acceleration, resulting in higher energy and better quality electron beams.

Contribution

First proof-of-principle experiment showing nanoparticle-assisted laser wakefield acceleration with improved electron beam characteristics.

Findings

Electron beams reached up to 338 MeV.

Energy spread was reduced to 4.7%.

Divergence was measured at 5.9 mrad.

Abstract

In the present work, we demonstrate for the first time a proof-of-principle experiment for nanoparticle-assisted laser wakefield acceleration. The nanoparticles, generated through laser ablation of aluminium, were introduced into the plasma and used to trigger the injection of electrons into the nonlinear plasma wake excited by a high power femtosecond laser. In this experiment, a significant enhancement of the electron beam energy, energy spread and divergence is obtained compared with the case when electrons are self-injected. The best quality electron bunches presented peak energy up to 338 MeV with a relative energy spread of 4.7% and vertical divergence of 5.9 mrad. This method can be further improved by adding an aerodynamic lens system, for instance, which would control the nanoparticle size, density, material and injection position thus allowing accurate control of the laser wakefield accelerator.