Attosecond Correlated Dynamics of Two Electrons Passing through a Transition State

Abstract

The strong-field induced decay of a doubly excited, transient Coulomb complex Ar**→Ar(2+)+2e(-) is explored by tracing correlated two-electron emission in nonsequential double ionization of Ar as a function of the carrier-envelope phase. Using <6 fs pulses, electron emission is essentially confined to one optical cycle. Classical model calculations support that the intermediate Coulomb complex has lost memory of its formation dynamics and allows for a consistent, though model-dependent definition of "emission time," empowering us to trace transition-state two-electron decay dynamics with sub-fs resolution. We find a most likely emission time difference of ∼200±100 as.

Channel-Resolved Above-Threshold Double Ionization of Acetylene

“…We hence exclude the mechanism of direct (e, 2e) ionization [39] for the hereobserved nonsequential double ionization. Alternatively, an intermediate doubly excited complex can be formed by multiple inelastic field-assisted recollisions [40][41][42][43][44][45], from which two coherently released electrons share a constant energy as observed in the nonsequential ATDI of argon atoms [20]. We expect a similar scenario of molecular nonsequential ATDI in our linearly polarized pulse, which is mostly sup pressed in a circularly polarized pulse by steering the electron trajectory away from the parent ion.…”

Non-sequential double ionization with near-single cycle laser pulses

“…Multiple recollisions complicate the electron dynamics and render the comparison with theory difficult. Recently, however, kinematically complete experiments succeeded in confining NSDI to a single laser cycle by using carrier-envelope phase (CEP)-controlled few- and near-single-cycle pulses 5, 6 . These experiments with near-single-cycle pulses allow for an easier comparison between theory and experiment.…”

Complete characterization of single-cycle double ionization of argon from the nonsequential to the sequential ionization regime

“…In conventional experiments using multicycle laser pulses, however, multiple recollisions of the first electron with the parent core may significantly complicate the NSDI dynamics [21,22], impeding quantitative comparison of experiment and theory. Confining NSDI to a single laser cycle using carrier-envelope phase (CEP)-tagged few- [23] and near-single-cycle [24,25] pulses has recently allowed the suppression of multiple recollisions, thus transposing the ideal conditions assumed in many models into the laboratory (see Ref. [26] for a recent review on single-cycle NSDI).…”