FEMTOSECOND 4-WAVE-MIXING EXPERIMENTS ON GAAS QUANTUM-WELLS USING 2 INDEPENDENTLY TUNABLE LASERS

Femtosecond two beam and three beam (omega(1),omega(1);omega(2)) four- wave mixing (FWM) experiments on GaAs quantum wells have been performe d using two partially synchronized, independently tunable lasers with external jitter compensation. Heavy and light hole beatings are observ ed with these two mutually incoherent lasers. FWM signals are observed when oz is completely below the exciton energies, with no spectral ov erlap with the absorption profile. These off-resonant signals are stro nger than the interband continuum signals for equivalent detunings.