We show that ionization of noble gas atoms by strong infrared circularly
polarized laser field under standard exerimental conditions can yield electrons
with up to 100% spin polarization in energy resolved measurements. Spin
polarization arises due to the interplay of the electron-core entanglement and
the sensitivity of ionization in circularly polarized fields to the sense of
electron rotation in the initial state.Comment: 10 pages, 2 figure