Tunneling dynamics in multiphoton ionization and attoclock calibration.

Area of Science:

• Atomic, Molecular, and Optical Physics
• Quantum Dynamics
• Strong-Field Physics

Background:

• Strong-field ionization is crucial for understanding electron dynamics in intense laser fields.
• The intermediate domain between tunneling and multiphoton ionization presents complex electron behavior.
• Accurate modeling is needed to interpret experimental results, such as those from the attoclock technique.

Purpose of the Study:

• To investigate the intermediate domain of strong-field ionization.
• To develop an intuitive model for ionization dynamics incorporating nonadiabatic effects.
• To explore the influence of these effects on electron wave packet behavior and Coulomb focusing.

Main Methods:

• Utilizing the strong-field approximation (SFA).
• Employing the imaginary-time method for theoretical analysis.
• Developing a nonadiabatic tunneling model with coordinate-dependent electron energy.

Main Results:

• Nonadiabatic effects induce transversal momentum shifts and delayed electron appearance.
• The tunneling exit shifts towards the ionic core, significantly altering Coulomb focusing.
• Including the Coulomb field during under-the-barrier motion amplifies nonadiabatic effects.

Conclusions:

• The modified simple man model provides an intuitive framework for understanding complex ionization dynamics.
• Nonadiabatic corrections are essential for accurate descriptions of electron behavior in strong laser fields.
• The findings have direct implications for calibrating and interpreting attoclock measurements.