Femtosecond tunable nonlinear absorption spectroscopy in Al0.1Ga0.9As.

Wavelength-tunable femtosecond absorption saturation measurements are combined with ensemble Monte Carlo simulations to investigate the dynamics of photoexcited carriers in Al 0.1 Ga 0.9 As. Continuum-generation and Fourier-synthesis techniques are used to generate tunable 40-fs optical pulses for the experiments. Carriers are excited to different initial states in the conduction band depending upon the wavelength selected for the experiment. The results of measurements in which the photon energies are either above or below the threshold for scattering from the Γ valley to the L valley are discussed