ULTRAFAST CARRIER DYNAMICS IN GASB

The ultrafast carrier dynamics in GaSb are studied using optical transmission-correlation spectroscopy with sub-100-fs pulses. The laser wavelength was tuned between 1.50 and 1.72 μm in order to differentiate between different scattering processes. The carriers scatter out of the initial distribution in 2-2.5 ps with a 200-350 fs component also observed. This faster component, usually attributed to phonon scattering, is observed below the assumed phonon emission threshold. When the laser is tuned above the intervalley scattering threshold a large fraction of the carriers rapidly scatter to the L valley. Saturation of the absorption is measured versus the pump power near the band edge.© 1995 American Institute of Physics.