Two-Dimensional Frequency Resolved Optomolecular Gating of High-Order Harmonic Generation

Area of Science:

• Quantum mechanics
• Molecular spectroscopy
• Nonlinear optics

Background:

• Probing electronic wave functions in polyatomic molecules presents significant challenges.
• Laser-molecule interactions are highly nonlinear, coupling various degrees of freedom.
• High-harmonic generation (HHG) is a powerful technique for studying electron dynamics.

Purpose of the Study:

• To disentangle the ionization and recombination steps in HHG.
• To develop advanced schemes for probing molecular electronic wave functions.
• To gain insight into the structural and dynamical properties of molecular systems.

Main Methods:

• Combining two-dimensional control of electron trajectories with vibrational control of molecules.
• Introducing frequency-resolved optomolecular gating (FROG) for temporal resolution of harmonic emission.
• Studying vibrational motion in dinitrogen tetroxide (N_{2}O_{4}).

Main Results:

• Successfully disentangled the ionization and recombination phases of HHG.
• Resolved the temporal amplitude and phase of harmonic emission from excited molecules.
• Demonstrated the capability of advanced schemes to provide unique insights into molecular properties.

Conclusions:

• Advanced HHG schemes offer unprecedented control and insight into molecular electronic structure.
• Frequency-resolved optomolecular gating is a key development for temporal analysis of HHG.
• The study provides a new pathway for understanding molecular dynamics and structural properties.