Recollision dynamics and phase diagram for nonsequential double ionization with circularly polarized laser fields

Area of Science:

• Atomic, Molecular, and Optical Physics
• Quantum Mechanics
• Laser-Matter Interactions

Background:

• Nonsequential double ionization (NDI) is a complex process in strong laser fields.
• Understanding NDI in circularly polarized fields is crucial for atomic physics.
• Previous experimental results for NDI in circular polarization appeared conflicting.

Purpose of the Study:

• To investigate the recollision dynamics in circularly polarized laser fields.
• To identify conditions leading to significant double ionization.
• To reconcile apparently conflicting experimental observations.

Main Methods:

• Development and application of a semiclassical quasistatic model.
• Analysis of electron trajectories and recollision dynamics.
• Derivation of an analytical formula for the NDI phase diagram.

Main Results:

• Identification of a specific velocity window for electron recollision.
• Correlation of significant double ionization with irregular return electron orbits.
• Successful reproduction of experimental data for magnesium.
• Explanation of conflicting experimental results via a phase diagram.

Conclusions:

• The semiclassical quasistatic model provides a robust framework for studying NDI.
• Electron orbit irregularity is a critical factor for NDI in circular polarization.
• The derived analytical formula clarifies the phase space of NDI, resolving experimental discrepancies.