Nonsequential Double Recombination in Intense Laser Fields

Abstract

A second plateau in the harmonic spectra of laser-driven two-electron atoms is observed both in the numerical solution of a low-dimensional model helium atom and using an extended strong field approximation. It is shown that the harmonics well beyond the usual cut-off are due to the simultaneous recombination of the two electrons, which were emitted during different, previous half-cycles. The new cut-off is explained in terms of classical trajectories. Classical predictions and the time-frequency analysis of the ab initio quantum results are in excellent agreement. The mechanism corresponds to the inverse single photon double ionization process in the presence of a (low frequency) laser field.

4 pages, RevTeX, v2 with an extended strong field approximation treatment of the process; instead, v1 describes an attosecond control scheme to enhance the process

References in corpus (3)

• A two-dimensional, two-electron model atom in a laser pulse: exact treatment, single active electron-analysis, time-dependent density functional theory, classical calculations, and non-sequential ionization
• Classical and quantum-mechanical treatments of nonsequential double ionization with few-cycle laser pulses
• Plasmon signatures in high harmonic generation

Cited by in corpus (20)

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• Non-Sequential Double Recombination High Harmonic Generation in Molecular-like Systems
• Same Period Emission and Recombination in Non-Sequential Double Recombination High-Harmonic Generation in H${}_2$
• Contribution of the pre-ionized H${}_2$ and the ionized H${}_2^{+}$ subsystems to the HHG Spectra of H${}_2$ in intense laser fields
• High-order harmonic generation from an atom in a disordered environment