Towards Zeptosecond-Scale Pulses from X-Ray Free-Electron Lasers

TL;DR

This paper proposes a novel method to generate zeptosecond-scale x-ray pulses with high peak power using existing FEL facilities, enabling new research in atomic and nuclear dynamics.

Contribution

A new technique utilizing a short 'afterburner' to produce few-cycle, high-power x-ray pulses with broad spectral bandwidth from current FELs.

Findings

Generation of trains of few-cycle pulses at GW peak power

Spectral bandwidth increased by up to two orders of magnitude

Potential applications in atomic, electronic, and nuclear dynamics

Abstract

The short wavelength and high peak power of the present generation of free-electron lasers (FELs) opens the possibility of ultra-short pulses even surpassing the present (tens to hundreds of attoseconds) capabilities of other light sources - but only if x-ray FELs can be made to generate pulses consisting of just a few optical cycles. For hard x-ray operation (~0.1nm), this corresponds to durations of approximately a single attosecond, and below into the zeptosecond scale. This talk will describe a novel method to generate trains of few-cycle pulses, at GW peak powers, from existing x-ray FEL facilities by using a relatively short 'afterburner'. Such pulses would enhance research opportunity in atomic dynamics and push capability towards the investigation of electronic-nuclear and nuclear dynamics. The corresponding multi-colour spectral output, with a bandwidth envelope increased by up to two orders of magnitudes over SASE, also has potential applications.