High-order above-threshold ionization with few-cycle pulse: a meter of the absolute phase

Area of Science:

• Quantum Optics
• Atomic, Molecular, and Optical Physics
• Strong Field Physics

Background:

• Above-threshold ionization (ATI) is a fundamental process in strong field physics.
• Understanding the carrier-envelope phase (CEP) dependence of ATI is crucial for controlling electron dynamics.
• Previous studies have explored CEP effects, but detailed analysis of angle-resolved spectra is ongoing.

Purpose of the Study:

• To theoretically investigate angle-resolved energy spectra of high-order ATI.
• To analyze the influence of the carrier-envelope phase (CEP) on these spectra.
• To explore the potential for determining the absolute phase from experimental measurements.

Main Methods:

• Numerical calculation of angle-resolved energy spectra for high-order ATI.
• Simulation using a linearly polarized four-cycle laser pulse.
• Analysis of spectra as a function of the carrier-envelope relative phase (absolute phase).

Main Results:

• Calculated spectra exhibit a distinct left-right (backward-forward) asymmetry.
• This asymmetry is directly correlated with the absolute phase of the laser pulse.
• High-energy electron emission occurs in ultrashort bursts (<0.7 fs), revealing spectral peak structures.

Conclusions:

• The observed spectral asymmetry provides a reliable method for determining the absolute phase in experiments.
• Analysis of peak structures in the spectra offers insights into the time-domain electron emission dynamics.
• These findings advance the understanding and control of electron dynamics in strong laser fields.