title: Terahertz pulse induced intervalley scattering in photoexcited GaAs.
abstract: Nonlinear transient absorption bleaching of intense few-cycle terahertz (THz) pulses is observed in photoexcited GaAs using opticalpump--THz-probe techniques. A simple model of the electron transport dynamics shows that the observed nonlinear response is due to THz-electric- field-induced intervalley scattering over sub-picosecond time scales as well as an increase in the intravalley scattering rate attributed to carrier heating. Furthermore, the nonlinear nature of the THz pulse transmission at high peak fields leads to a measured terahertz conductivity in the photoexcited GaAs that deviates significantly from the Drude behavior observed at low THz fields, emphasizing the need to explore nonlinear THz pulse interactions with materials in the time domain.
authors.affiliation: Department of Physics, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: F H
authors.initials: FH
authors.lastname: Su
authors.forename: F
authors.initials: F
authors.lastname: Blanchard
authors.forename: G
authors.initials: G
authors.lastname: Sharma
authors.forename: L
authors.initials: L
authors.lastname: Razzari
authors.forename: A
authors.initials: A
authors.lastname: Ayesheshim
authors.forename: T L
authors.initials: TL
authors.lastname: Cocker
authors.forename: L V
authors.initials: LV
authors.lastname: Titova
authors.forename: T
authors.initials: T
authors.lastname: Ozaki
authors.forename: J-C
authors.initials: JC
authors.lastname: Kieffer
authors.forename: R
authors.initials: R
authors.lastname: Morandotti
authors.forename: M
authors.initials: M
authors.lastname: Reid
authors.forename: F A
authors.initials: FA
authors.lastname: Hegmann
mesh_terms: D001152:Arsenicals / Q000737:chemistry* / Q000528:radiation effects*; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005708:Gallium / Q000737:chemistry* / Q000528:radiation effects*; D055096:Optical Devices; D015203:Reproducibility of Results; D012542:Scattering, Radiation; D012680:Sensitivity and Specificity; D055053:Terahertz Radiation
chemical_list: D001152:Arsenicals; C043055:gallium arsenide; D005708:Gallium