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Spin asymmetry in an intense-field ionization process
F H M Faisal1, S Bhattacharyya
1Fakultät für Physik, Universität Bielefeld, Postfach 100131, D-33501 Bielefeld, Germany.
Physical Review Letters
|August 25, 2004
Summary
Relativistic analysis reveals an intensity-dependent spin flip asymmetry in hydrogen atom ionization by laser fields. This spin asymmetry is independent of magnetic fields and spin-orbit interactions, offering new control pathways.
Area of Science:
- Atomic physics
- Quantum optics
- Relativistic quantum mechanics
Background:
- Understanding electron spin dynamics during ionization is crucial in atomic physics.
- Circularly polarized laser fields can induce spin polarization in atomic systems.
- Relativistic effects become significant for high-energy interactions and heavy atoms.
Purpose of the Study:
- To investigate the spin flip rates and resulting electron currents in hydrogen atoms under intense laser fields.
- To analyze the relativistic effects on spin polarization during ionization.
- To explore the origin and control of spin asymmetry in electron currents.
Main Methods:
- Relativistic quantum mechanical analysis of Dirac hydrogen atoms.
- Calculation of ionization rates and electron currents.
- Investigation of spin-up and spin-down electron emission.
Main Results:
- A significant intensity-dependent asymmetry between spin-up and spin-down electron currents was observed.
- This asymmetry persists even when magnetic field effects (retardation) and spin-orbit interactions are negligible.
- The sign of the observed asymmetry can be controlled by altering the laser photon helicity.
Conclusions:
- The study identifies a novel source of spin asymmetry in laser-induced ionization, distinct from established mechanisms.
- This finding offers a new method to control electron spin polarization by manipulating laser properties.
- The relativistic treatment is essential for accurately describing these spin-dependent phenomena.