Spatially and temporally controlling electron spin polarization in strong-field ionization using orthogonal two-color laser fields

Abstract

We propose a scheme to produce spatially and temporally controlled spin-polarized photoelectrons by strong-field ionization of atoms. We calculate the momentum-resolved electron spin polarization from two spin-orbit coupled ionic states ($J=1/2$ and $J=3/2$) of krypton atoms in orthogonal two-color laser fields using the strong-field approximation, and obtain the instantaneous spin-polarization degree. With this scheme, the spin-up and -down photoelectrons can be well separated in the space, and the spin polarization is controlled on the sub-laser-cycle timescale. This study illustrates and reveals the mechanism of the generation of spin-polarized photoelectrons with an arbitrary spatially and temporally tailored laser field. We expect this work has implications for controlling the spatiotemporal spin polarization in strong-field physics.