Polarization-state beating in four-wave-mixing experiments on ZnSe epilayers

The polarization angle of the time-integrated four-wave-mixing signal from a ZnSe epilayer is found to oscillate as a function of the delay time between the two incident pulses, the modulation depth being dependent on the polarization angle between the incident pulses. The oscillation is shown to be a feature of heavy-hole–light-hole quantum beating, and is described by a solution of the optical Bloch equations.