title: Anisotropy of excitation and relaxation of photogenerated charge carriers in graphene.
abstract: We present a pump-probe experiment on graphene, which reveals a pronounced dependence of the pump-induced transmission on the angle between pump and probe polarization. It reflects a strong anisotropy of the pump-induced occupation of photogenerated carriers in momentum space. Within 150 fs after excitation, an isotropic carrier distribution is established. The experiments are well described by microscopic modeling, which identifies carrier-phonon scattering to be the main relaxation mechanism giving rise to an isotropic carrier distribution.
authors.affiliation: Helmholtz-Zentrum Dresden-Rossendorf, P.O. Box 510119, 01314 Dresden, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Mittendorff
authors.forename: Torben
authors.initials: T
authors.lastname: Winzer
authors.forename: Ermin
authors.initials: E
authors.lastname: Malic
authors.forename: Andreas
authors.initials: A
authors.lastname: Knorr
authors.forename: Claire
authors.initials: C
authors.lastname: Berger
authors.forename: Walter A
authors.initials: WA
authors.lastname: de Heer
authors.forename: Harald
authors.initials: H
authors.lastname: Schneider
authors.forename: Manfred
authors.initials: M
authors.lastname: Helm
authors.forename: Stephan
authors.initials: S
authors.lastname: Winnerl