Spin-Polarized Photoelectrons in the Vicinity of Spectral Features

It has been shown by Fano (1969) https://doi.org/10.1103/PhysRev.178.131 that photoionization of a cæsium atom by a laser pulse tuned to the vicinity of a Cooper minimum generates spin-polarized electrons. Here we show that while photoionization of rare gases does not provide large spin polarization in the vicinity of the Cooper minimum, the Fano resonances yield much higher overall spin polarization ($\ge 40\mathrm{\%}$). The spin polarization increases in angle-resolved photoelectron spectra, and reaches $100\mathrm{\%}$ when measured in coincidence with the photoion. We provide a general framework for achieving spin polarization in photoionization irrespective of the ionization regime.