Above-threshold ionization with highly charged ions in superstrong laser fields. III. Spin effects and their dependence on laser polarization

Abstract

Spin effects in the tunneling regime of strong-field ionization of hydrogenlike highly charged ions in linearly as well as circularly polarized laser fields are investigated. The impact of the polarization of a laser field on the spin effects is analyzed. Spin-resolved differential ionization rates are calculated employing the relativistic Coulomb-corrected strong-field approximation developed in the previous paper of the series. Analytical expressions for spin asymmetries and the spin-flip probability, depending on the laser's polarization, are obtained for the photoelectron momentum corresponding to the maximum of the tunneling probability. A simple intuitive model is developed for the description of spin dynamics in tunnel ionization. The spin flip is shown to be experimentally observable by using moderate highly charged ions with a charge of the order of 20 and a laser field with an intensity of $I\ensuremath{\sim}{10}^{22}\phantom{\rule{0.28em}{0ex}}{\mathrm{W}/\mathrm{cm}}^{2}$.