Time-resolved recombination by attosecond-controlled high harmonic generation.

Area of Science:

• Quantum optics
• Strong-field physics
• Attosecond science

Background:

• High-harmonic generation (HHG) is a key process for producing extreme ultraviolet and X-ray light.
• Understanding electron dynamics during ionization is crucial for controlling HHG.
• Isolated attosecond pulses enable probing ultrafast electron motion.

Purpose of the Study:

• To theoretically investigate coherent control of strong-field high-harmonic generation.
• To analyze the origin of interference structures in delay-dependent spectra.
• To develop a method for observing electron ionization dynamics in attosecond resolution.

Main Methods:

• Theoretical investigation of coherent control.
• Analysis of strong-field high-harmonic generation in the presence of an isolated attosecond pulse.
• Comparison between classical trajectory models and quantum mechanical calculations.

Main Results:

• Rapid modulation of the controlled signal shows interference fringe structures in spectra.
• Fringes result from the interference between photon- and tunneling-initiated recombination pathways.
• Relative recombination times for both pathways are reconstructed from the interference fringes.

Conclusions:

• Coherent control offers a novel scheme for optical observation.
• The study provides insights into the interplay of photoionization and tunneling ionization electron dynamics.
• Attosecond resolution of electron dynamics is achievable through spectral interference analysis.