Modulation of attosecond beating in resonant two-photon ionization

Area of Science:

• Quantum dynamics
• Atomic physics
• Attosecond science

Background:

• Photoelectron attosecond beating arises from quantum interference in multi-photon ionization.
• Autoionizing states significantly influence ionization dynamics and photoelectron spectra.
• Understanding these phenomena is crucial for attosecond spectroscopy and coherent control.

Purpose of the Study:

• To theoretically investigate photoelectron attosecond beating due to two-photon transitions.
• To analyze the influence of autoionizing states on attosecond beating.
• To develop a model for reconstructing coherent metastable wave packets.

Main Methods:

• Theoretical study employing a general analytical model.
• Analysis of two-photon transitions in the presence of autoionizing states.
• Comparison with ab initio calculations for the helium atom.

Main Results:

• Harmonic traversal of a resonance causes significant variations in phase shift and frequency of sideband beating.
• Beating persists even with non-overlapping pump and probe pulses.
• The analytical model accurately predicts phenomena observed in helium atom calculations.

Conclusions:

• Photoelectron attosecond beating provides a nonholographic interferometric method to reconstruct coherent metastable wave packets.
• The developed model offers a robust framework for studying multi-resonant two-photon processes.
• This work advances the understanding of electron dynamics in atoms and molecules.