Multi-GeV Electron Bunches from an All-Optical Laser Wakefield Accelerator

Abstract

We present the first demonstration of multi-GeV laser wakefield acceleration in a fully optically formed plasma waveguide, with an acceleration gradient as high as 25 GeV=m. The guide was formed via self- waveguiding of <15 J, 45 fs (< ∼ 300 TW) pulses over 20 cm in a low-density hydrogen gas jet, with accelerated electron bunches driven up to 5 GeV in quasimonoenergetic peaks of relative energy width as narrow as ∼15%, with divergence down to ∼1 mrad and charge up to tens of picocoulombs. Energy gain is inversely correlated with on-axis waveguide density in the range Ne = (1.3-3.2)E17/cc. We find that shot-to-shot stability of bunch spectra and charge are strongly dependent on the pointing of the injected laser pulse and gas jet uniformity. We also observe evidence of pump depletion-induced dephasing, a consequence of the long optical guiding distance. 

DOI: https://doi.org/10.1103/PhysRevX.12.031038