Sub-cycle attosecond control in frustrated double ionization of molecules

A Vilà,A Emmanouilidou,G P Katsoulis

doi:10.1088/1361-6455/aaf012

Abstract

We demonstrate sub-cycle control of frustrated double ionization (FDI) of the two-electron triatomic molecule when driven by two orthogonally polarized two-color laser fields, where a weak mid-infrared laser field is employed to probe the FDI process triggered by a strong near-infrared laser field. We use a three-dimensional semi-classical model that fully accounts for the electron and nuclear motion in strong fields. We analyze the FDI probability and the distribution of the momentum of the escaping electron along the polarization direction of the mid-infrared laser field. These observables when considered in conjunction bear clear signatures of sub-cycle control of FDI. We find that the momentum distribution of the escaping electron has a striking hive-shape with features that can accurately be mapped to the time that one of the two electrons tunnel-ionizes at the start of the break-up process. This mapping distinguishes consecutive tunnel-ionization times within a cycle of the mid-infrared laser field but not tunnel-ionization times differing by an integer number of cycles.

Highlights

Accounting for roughly 10% of all ionization events, frustrated double ionization (FDI) is one of the major processes when multi-center molecules are driven by intense laser fields [1, 2]
We find that the FDI probability changes as a function of the time delay
We find that pathway B with a probability that varies significantly from 2.6% to 0% is the main reason for the change in the FDI probability

Summary

Introduction

Accounting for roughly 10% of all ionization events, frustrated double ionization (FDI) is one of the major processes when multi-center molecules are driven by intense laser fields [1, 2]. In frustrated ionization an electron first tunnel-ionizes in the driving laser field. Due to the electric field of the laser pulse, it is recaptured by the parent ion in a Rydberg state [3]. In FDI an electron escapes and another one occupies a Rydberg state at the end of the laser pulse. Two pathways were identified to underlie FDI in previous theoretical studies of strongly-driven two-electron diatomic and triatomic molecules [2, 7]. Electron–electron correlation is important, primarily, for one of the two pathways

Methods

Results

Conclusion