Thomson backscattering from laser generated, relativistically moving high-density electron layers

TL;DR

This paper demonstrates that XUV radiation can be generated through Thomson backscattering from relativistically moving electron layers produced by high-intensity laser irradiation of thin foils, providing insights into electron sheath dynamics.

Contribution

It presents an all-optical experimental setup for Thomson backscattering from relativistic electron layers, revealing spectral and temporal characteristics of the emitted XUV radiation.

Findings

XUV radiation produced in a broad spectral range of tens of eV.

Maximum scattering occurs 100 fs after laser irradiation, indicating hot electron flux peak.

Results offer time-resolved insights into electron sheath evolution and ion acceleration dynamics.

Abstract

We show experimentally that XUV radiation is produced when a laser pulse is Thomson backscattered from sheets of relativistic electrons which are formed at the rear-surface of a foil irradiated on its front side by a high-intensity laser. An all-optical setup is realized using the Jena Titanium:Sapphire TW laser system (JETI). The main pulse is split into two pulses: one to accelerate electrons from thin aluminum foil targets to energies of the order of some MeV and the other, counterpropagating probe pulse is Thomson-backscattered off these electrons when they exit the target rear side. The process produced photons within a wide spectral range of some tens of eV as a result of the broad electron energy distribution. The highest scattering intensity is observed when the probe pulse arrives at the target rear surface 100 fs after the irradiation of the target front side by the pump pulse, corresponding to the maximum flux of hot electrons at the interaction region. These results can provide time-resolved information about the evolution of the rear-surface electron sheath and hence about the dynamics of the electric fields responsible for the acceleration of ions from the rear surface of thin, laser-irradiated foils.