title: Spin relaxation by transient monopolar and bipolar optical orientation.
abstract: We have used two-color time-resolved spectroscopy to measure the relaxation of electron spin polarizations in a bulk semiconductor. The circularly polarized pump beam induces a polarization either by direct excitation from the valence band, or by free-carrier (Drude) absorption when tuned to an energy below the band gap. We find that the spin relaxation time, measured with picosecond time resolution by resonant induced Faraday rotation in both cases, increases in the presence of photogenerated holes. In the case of the material chosen, n-InSb, the increase was from 14 to 38 ps.
authors.affiliation: Advanced Technology Institute, University of Surrey, Guildford GU2 7XH, United Kingdom.
authors.forename: B N
authors.initials: BN
authors.lastname: Murdin
authors.forename: K
authors.initials: K
authors.lastname: Litvinenko
authors.forename: D G
authors.initials: DG
authors.lastname: Clarke
authors.forename: C R
authors.initials: CR
authors.lastname: Pidgeon
authors.forename: P
authors.initials: P
authors.lastname: Murzyn
authors.forename: P J
authors.initials: PJ
authors.lastname: Phillips
authors.forename: D
authors.initials: D
authors.lastname: Carder
authors.forename: G
authors.initials: G
authors.lastname: Berden
authors.forename: B
authors.initials: B
authors.lastname: Redlich
authors.forename: A F G
authors.initials: AF
authors.lastname: van der Meer
authors.forename: S
authors.initials: S
authors.lastname: Clowes
authors.forename: J J
authors.initials: JJ
authors.lastname: Harris
authors.forename: L F
authors.initials: LF
authors.lastname: Cohen
authors.forename: T
authors.initials: T
authors.lastname: Ashley
authors.forename: L
authors.initials: L
authors.lastname: Buckle