Two-wavelength (visible/infrared) femtosecond spectroscopy of the dynamics of holes in GaAs

Summary form only given.This paper reports results on the ultrafast dynamics of holes in GaAs measured using a recently developed broadly tunable femtosecond optical parametric oscillator. With this source it is possible to pump valence-to-conduction band transitions with visible pulses and probe the generated holes using mid-infrared pulses, which excite transitions between the heavy- or light-hole bands and the split-off band. The advantage of such a two-wavelength spectroscopic measurement is that both the pumping and the probing take place between a fully empty or fully occupied band and a band occupied by only the carriers of interest.