Attosecond electron bunches from a nanofiber driven by Laguerre-Gaussian laser pulses

Li-Xiang Hu,Jorge Vieira,Paul McKenna,Yan Yin,Fu-Qiu Shao,De-Bin Zou,Zheng-Ming Sheng,Tong-Pu Yu

doi:10.1038/s41598-018-25421-9

Abstract

Generation of attosecond bunches of energetic electrons offers significant potential from ultrafast physics to novel radiation sources. However, it is still a great challenge to stably produce such electron beams with lasers, since the typical subfemtosecond electron bunches from laser-plasma interactions either carry low beam charge, or propagate for only several tens of femtoseconds. Here we propose an all-optical scheme for generating dense attosecond electron bunches via the interaction of an intense Laguerre-Gaussian (LG) laser pulse with a nanofiber. The dense bunch train results from the unique field structure of a circularly polarized LG laser pulse, enabling each bunch to be phase-locked and accelerated forward with low divergence, high beam charge and large beam-angular-momentum. This paves the way for wide applications in various fields, e.g., ultrabrilliant attosecond x/γ-ray emission.

Highlights

The generation of ultrashort intense laser pulses pushes the laser-matter interaction to the relativistic regime where the relativistic electron dynamics in the laser fields become dominant
We report an innovative scheme to generate a dense attosecond electron bunch train efficiently from a laser-driven nanofiber target
The dense attosecond bunch train results from the unique field structure of the circularly polarized LG laser pulse, enabling each bunch to converge into a dense disk and propagate with a narrow energy spread, high beam charge and large beam-angular-momentum (BAM)

Summary

Introduction

The generation of ultrashort intense laser pulses pushes the laser-matter interaction to the relativistic regime where the relativistic electron dynamics in the laser fields become dominant. This leads to the production of ultrashort x-ray radiation sources with duration down to the attosecond level[6], where femtosecond and even attosecond relativistic electron bunches with a narrow energy spread, small divergence angle and large flux are of crucial importance[7] For this purpose, significant efforts have been dedicated to acquiring high-quality ultrashort electron bunches using the normal Gaussian laser pulses, for example, by laser irradiating high density plasma boundaries of a channel, hollow cone, wire or droplet target[8,9,10,11,12,13,14,15], underdense plasmas[16,17] or nanofilms[18,19], by the inverse FEL process[20], direct laser acceleration in vacuum[21], or by a relativistic electron beam scattering off interfering laser waves[22]. Full three-dimensional (3D) particle-in-cell (PIC) simulations indicate that the stable attosecond structure remains intact for several hundreds of femtoseconds, paving the way for many potential applications in various fields

Methods

Results

Conclusion