Two-photon double ionization of neon using an intense attosecond pulse train

B Manschwetus,L Rading,T Mohamed,S Maclot,H Wikmark,F Campi,B Farkas,A L'Huillier,P Johnsson,H Coudert-Alteirac,C M Heyl,J Lahl,P Rudawski

doi:10.1103/physreva.93.061402

Abstract

We present the first demonstration of two-photon double ionization of neon using an intense extreme ultraviolet (XUV) attosecond pulse train (APT) in a photon energy regime where both direct and sequential mechanisms are allowed. For an APT generated through high-order harmonic generation (HHG) in argon we achieve a total pulse energy close to 1 $\mu$J, a central energy of 35 eV and a total bandwidth of $\sim30$ eV. The APT is focused by broadband optics in a neon gas target to an intensity of $3\cdot10^{12} $W$\cdot$cm$^{-2}$. By tuning the photon energy across the threshold for the sequential process the double ionization signal can be turned on and off, indicating that the two-photon double ionization predominantly occurs through a sequential process. The demonstrated performance opens up possibilities for future XUV-XUV pump-probe experiments with attosecond temporal resolution in a photon energy range where it is possible to unravel the dynamics behind direct vs. sequential double ionization and the associated electron correlation effects.

Highlights

Double photoionization of atoms or molecules can occur through the absorption of either a single energetic photon or several less energetic photons
We present a demonstration of two-photon double ionization of neon using an intense extreme ultraviolet (XUV) attosecond pulse train (APT) in a photon energy regime where both direct and sequential mechanisms are allowed
For an APT generated through high-order harmonic generation (HHG) in argon we achieve a total pulse energy close to 1 μJ, a central energy of 35 eV, and a total bandwidth of ∼30 eV

Summary

Introduction

Double photoionization of atoms or molecules can occur through the absorption of either a single energetic photon or several less energetic photons. We present a demonstration of two-photon double ionization of neon using an intense extreme ultraviolet (XUV) attosecond pulse train (APT) in a photon energy regime where both direct and sequential mechanisms are allowed.

Results

Conclusion