Optical coherent control and phase shift of excitonic and biexcitonic four-wave-mixing polarization

Abstract

The optical coherent control of the exciton–biexciton system is studied in four-wave-mixing (FWM) experiments on a ZnSe single-quantum well. Coherent control is achieved by applying a pair of phase-locked laser pulses which produce an FWM signal in combination with an additional third pulse. Oscillations as a function of the interpulse delay time are observed in the FWM signal at the energetic position of the exciton and biexciton resonance, respectively. A phase shift between these oscillations is found for certain orders of arrival of the excitation pulses at the sample. This clearly demonstrates that the coherent control acts in different ways: if the phase shift is observed the FWM polarization is coherently controlled. Otherwise, the coherent control just involves the polarization induced by the two phase-locked pulses.