Two-photon ionization of trivalent atoms as a source of polarized electrons

It is argued that photo-electrons emitted from trivalent atoms in a two-photon ionization process are totally polarized if the incident light is of total circular polarization and its wavelength matches the resonance condition for the transition between ground state (n 2 P 1 2/) and the first excited state (n+1) 2 S 1 2/. The estimated photoionization yield compares favourably with that of the analogous process in alkali atoms. Some of the most important conditions for a successful experiment are considered.