Coulomb asymmetry in above-threshold ionization.

Area of Science:

• Atomic Physics
• Quantum Mechanics
• Strong-Field Physics

Background:

• Strong-field laser-atom interactions are crucial for understanding electron dynamics.
• Photoelectron angular distributions reveal key information about electron emission processes.
• The influence of the Coulomb potential on tunneling electrons is not fully understood.

Purpose of the Study:

• To develop a novel theoretical method for including Coulomb potential effects in strong-field laser-atom interactions.
• To investigate the origin of photoelectron angular asymmetry, particularly for elliptically polarized light.
• To compare theoretical predictions with experimental data for validation.

Main Methods:

• A new theoretical model was developed to account for the Coulomb potential.
• The model was applied to analyze energy-resolved angular distributions of photoelectrons.
• Simulations were performed for conditions involving elliptical laser polarization.

Main Results:

• The model successfully reproduces experimental data for photoelectron angular distributions.
• A strong asymmetry was observed in the photoelectron angular distributions for elliptical polarization.
• The study identifies the Coulomb force acting just after tunneling as the cause of low-energy electron asymmetry.

Conclusions:

• The Coulomb potential plays a significant role in shaping photoelectron angular distributions, especially at low energies.
• The mechanism for asymmetry differs between low-energy (Coulomb-induced) and high-energy (rescattering-induced) photoelectrons.
• This new method provides a more accurate description of strong-field laser-atom interactions.