Photo-induced spin filtering in a double quantum dot

We investigate the spin-dependent electron dynamics in a double quantum dot driven by sub-picosecond asymmetric electromagnetic pulses. We show analytically that applying the appropriate pulses, specified here, allows a spin separation on a femtosecond time scale in the sense that states with a desired spin projection are localized mainly on one of the dots. It is shown how to maintain in time this photo-induced spin-dependent filtering.