Electron rescattering in a bicircular laser field

Area of Science:

• Atomic and Molecular Physics
• Quantum Optics
• Strong-Field Physics

Background:

• Above-threshold ionization (ATI) is a fundamental process in strong-field physics.
• Understanding electron dynamics in intense laser fields is crucial for attosecond science and high-harmonic generation.
• Bicircular fields offer unique symmetries not present in linear or circular fields.

Purpose of the Study:

• To theoretically investigate above-threshold ionization (ATI) of rare-gas atoms using a bicircular laser field.
• To analyze the contributions of direct and rescattered electrons to the ionization spectrum.
• To explore the role of discrete rotational symmetry in shaping the electron momentum distribution.

Main Methods:

• Employed the improved strong-field approximation (SFA) for theoretical calculations.
• Calculated and visualized quantum orbits leading to specific final electron states.
• Analyzed angle-dependent electron spectra and velocity maps.

Main Results:

• The angle-dependent electron spectrum exhibits discrete rotational symmetry inherent to the bicircular field.
• Backward-scattered electrons show similarities to linear polarization cases, with rotational symmetry-induced variations.
• Forward-scattered electrons significantly influence the low-momentum velocity map.
• Direct electron spectra display reflection symmetry, which is disrupted by rescattering effects.

Conclusions:

• Bicircular fields provide a unique platform to study electron dynamics and symmetry in ATI.
• The interplay between direct and rescattered electrons leads to complex spectral features.
• The findings offer insights into controlling electron trajectories and understanding fundamental light-matter interactions.