Coherent control of electron–phonon scattering and the dephasing process in gallium arsenide multiple quantum wells

Exciton-folded acoustic phonon scattering has been observed in three types of GaAs multiple quantum wells (MQWs) by using four-wave-mixing spectroscopy. The energies of the phonons correspond exactly to those of the folded acoustic phonons calculated by the Rytov model in each MQW. We show the coherent control of the exciton–phonon scattering by the phase-locked pulses irradiation. The phenomenological dephasing time in the long-time region does not depend on the scattering. However, the magnitude of the diffracted signal intensity increases (decreases) when the exciton–phonon scattering is suppressed (amplified) at time less than the correlation, or memory time.