Modulation of attosecond beating in resonant two-photon ionization

Abstract

We present a theoretical study of the photoelectron attosecond beating at the basis of RABBIT (Reconstruction of Attosecond Beating By Interference of Two-photon transitions) in the presence of autoionizing states. We show that, as a harmonic traverses a resonance, its sidebands exhibit a peaked phase shift as well as a modulation of the beating frequency itself. Furthermore, the beating between two resonant paths persists even when the pump and the probe pulses do not overlap, thus providing a sensitive non-holographic interferometric means to reconstruct coherent metastable wave packets. We characterize these phenomena quantitatively with a general finite-pulse analytical model that accounts for the effect of both intermediate and final resonances on two-photon processes, at a negligible computational cost. The model predictions are in excellent agreement with those of accurate ab initio calculations for the helium atom in the region of the N=2 doubly excited states.

References in corpus (7)

• Phase Measurement of Resonant Two-Photon Ionization in Helium
• Decoherence in Attosecond Photoionization
• Study of attosecond delays using perturbation diagrams and exterior complex scaling
• Theory of ultrafast autoionization dynamics of Fano resonances
• Photoabsorption of attosecond XUV light pulses by two strongly laser-coupled autoionizing states
• Laser-assisted-autoionization dynamics of helium resonances with single attosecond pulses
• Probing dipole-forbidden autoionizing states by isolated attosecond pulses

Cited by in corpus (5)

• Attosecond dynamics through a Fano resonance: Monitoring the birth of a photoelectron
• Attosecond delays in molecular photoionization
• Attosecond delays in laser-assisted photodetachment from closed-shell negative ions
• Quantum coherent control of the photo\-electron angular distribution in bichromatic ionization of atomic neon
• Attosecond time delay in the photoionization of Mn in the region of the $3p\to 3d$ giant resonance