Exploring tunneling time by instantaneous ionization rate in strong-field ionization

Area of Science:

• Quantum mechanics
• Atomic physics
• Strong-field physics

Background:

• Tunneling time is a fundamental quantum mechanical concept.
• Precisely measuring tunneling time in atomic systems remains challenging.
• Previous methods often rely on indirect or less precise measurements.

Purpose of the Study:

• To introduce a novel quantum approach for investigating tunneling time.
• To establish a method for characterizing tunneling time using ionization dynamics.
• To explore tunneling time in atoms subjected to different polarization states of light.

Main Methods:

• Utilizing a quantum mechanical framework to model atomic ionization.
• Supervising the instantaneous ionization rate in response to laser pulses.
• Analyzing the temporal delay between electric field maxima and ionization peaks.
• Investigating both linearly and circularly polarized laser pulses.

Main Results:

• A significant time delay was observed between the peak electric field intensity and the peak ionization rate for linearly polarized pulses.
• This measurable time delay serves as a characterization of tunneling time.
• For circularly polarized pulses and anisotropic atoms, tunneling time can be defined by the delay between peak ionization and the electric field's alignment with maximum electron density.

Conclusions:

• The proposed quantum approach provides a viable method for measuring tunneling time.
• Ionization dynamics offer a sensitive probe for quantifying this fundamental quantum phenomenon.
• The findings are applicable to understanding electron behavior in strong laser fields.