Control of Photon Polarization in GaAs/AlAs Single Quantum Dot Emission

We study polarization resolved correlation between photons emitted in cascaded biexciton-exciton recombination from a single quantum dot formed in type II GaAs/AlAs bilayer. Magnetic field induced transition from anisotropy controlled to the Zeeman controlled emission was demonstrated by a circular polarization correlation between the emitted photons. A simple model describing the effect allowed us to determine the anisotropic exchange splitting of the excitonic state. This method of the anisotropic exchange splitting determination can be useful in the case when other methods are not sensitive enough.