Abstract
A three‐pulse transient grating technique was used to measure the carrier dynamics in photoexcited GaAs. The four‐wave mixing signal exhibits a two component relaxation of different magnitudes for various probe energies. The fast relaxation mechanism is due to electrons in the L valleys scattering back to the Γ valley. The effective transfer time for L→Γ was found to be ≊8 ps. The slower relaxation arises from carrier recombination.