title: Quantum interference control of ballistic pure spin currents in semiconductors.
abstract: We demonstrate all-optical quantum interference injection and control of a ballistic pure spin current (without an accompanying charge current) in GaAs/AlGaAs quantum wells, consisting of spin-up electrons traveling in one direction and spin-down electrons traveling in the opposite direction. This current is generated through quantum interference of one- and two-photon absorption of approximately 100 fs phase-locked pulses that have orthogonal linear polarizations. We use a spatially resolved pump-probe technique to measure carrier movement of approximately 10 nm. Results agree with recent theoretical predictions.
authors.affiliation: Laboratory for Photonics & Quantum Electronics, 138 IATL, University of Iowa, Iowa City, Iowa 52242, USA.
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Stevens
authors.forename: Arthur L
authors.initials: AL
authors.lastname: Smirl
authors.forename: R D R
authors.initials: RD
authors.lastname: Bhat
authors.forename: Ali
authors.initials: A
authors.lastname: Najmaie
authors.forename: J E
authors.initials: JE
authors.lastname: Sipe
authors.forename: H M
authors.initials: HM
authors.lastname: Van Driel