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 dyna mics of photoexcited carriers in Al0.1Ga0.9As. Continuum-generation an d Fourier-synthesis techniques are used to generate tunable 40-fs opti cal pulses for the experiments. Carriers are excited to different init ial states in the conduction band depending upon the wavelength select ed for the experiment. The results of measurements in which the photon energies are either above or below the threshold for scattering from the GAMMA valley to the L valley are discussed. Quantitative agreement between experiment and theory is demonstrated for a deformation poten tial D(GAMMA-L)GAMMA of 5 X 10(8) eV/cm.