Direct laser acceleration of electrons in free-space

TL;DR

This paper reports the first observation of direct laser acceleration of non-relativistic electrons using ultra-intense radially polarized lasers, achieving multi-GeV/m gradients without a medium, enabling new compact accelerator technologies.

Contribution

It demonstrates a novel medium-free laser acceleration method with highly-directional, high-gradient electron acceleration, advancing the field of laser-driven particle accelerators.

Findings

First observation of direct longitudinal laser acceleration of non-relativistic electrons

Achieved multi-GeV/m accelerating gradients in free space

Potential to generate relativistic attosecond electron bunches and x-ray pulses

Abstract

Compact laser-driven accelerators are versatile and powerful tools of unarguable relevance on societal grounds for the diverse purposes of science, health, security, and technology because they bring enormous practicality to state-of-the-art achievements of conventional radio-frequency accelerators. Current benchmarking laser-based technologies rely on a medium to assist the light-matter interaction, which impose material limitations or strongly inhomogeneous fields. The advent of few cycle ultra-intense radially polarized lasers has materialized an extensively studied novel accelerator that adopts the simplest form of laser acceleration and is unique in requiring no medium to achieve strong longitudinal energy transfer directly from laser to particle. Here we present the first observation of direct longitudinal laser acceleration of non-relativistic electrons that undergo highly-directional multi-GeV/m accelerating gradients. This demonstration opens a new frontier for direct laser-driven particle acceleration capable of creating well collimated and relativistic attosecond electron bunches and x-ray pulses.