Narrow high-frequency spectral features via laser-induced slow spin flips

Abstract

The process of high harmonic generation in the tunneling regime of laser-driven atomic systems is investigated numerically with the Pauli equation. For an ion with electron wave packet in the ground state with spin-up orientation, a small fraction of the tunneled wave packet will be transformed into the spin-down orientation prior to the recollision with the ionic core due to the magnetic field component of the laser field. We show that the high-frequency harmonics associated with the wave packet in spin-down orientation, though weak in intensity, have a substantially reduced line width with respect to those without spin flip.