Femtosecond photon echo and four-wave mixing studies on GaAs/AlGaAs heterostructure at room temperature

We report femtosecond photon echo and four-wave mixing measurements performed on GaAs/AlGaAs heterostructure at room temperature. In femtosecond photon echo experiment the dephasing time was obtained, found to vary between 40 and 55 fs depending on carrier density. The dependence showed a power-law behavior T-2 alpha N-0.22, which indicates that major phase coherence loss is due to screened Coulomb electron-electron interaction. Transient grating experiments yielded the electron diffusion coefficient value of 200 cm(2)/s and electron relaxation time equal to 3 ns.