Resolving Ultrafast Spin-Orbit Dynamics in Heavy Many-Electron Atoms.

Area of Science:

• Atomic Physics
• Quantum Mechanics
• Ultrafast Spectroscopy

Background:

• Atomic systems exhibit complex behaviors when interacting with intense laser fields.
• Autoionizing states are crucial for understanding electron dynamics in atoms.
• Extreme ultraviolet (XUV) ultrashort pulses offer precise control over atomic excitation.

Purpose of the Study:

• To investigate the excitation pathways to autoionizing states in krypton using time-delayed XUV pulses.
• To control and observe the population dynamics of autoionizing levels through their decay.
• To explore the role of spin-orbit effects in ultrafast atomic processes.

Main Methods:

• Utilizing R-matrix with time-dependence theory, incorporating spin-orbit effects.
• Employing two time-delayed, cross-polarized extreme ultraviolet ultrashort pulses.
• Analyzing the population of autoionizing states via their subsequent decay patterns.

Main Results:

• Demonstrated control over excitation pathways to krypton autoionizing states by adjusting the time delay between pulses.
• Successfully isolated a two-photon excitation pathway using cross-polarized light.
• Observed and analyzed the decay dynamics of populated autoionizing levels.

Conclusions:

• Time-delayed ultrafast pulses provide a powerful tool for manipulating atomic excitation pathways.
• The R-matrix method with time-dependence is effective for studying complex atomic dynamics, including spin-orbit interactions.
• This research offers insights into controlling electron dynamics in atoms using tailored laser pulses.