Quantum dots: a source of multicolor photons with tunable statistics and correlated polarizations

We report on measurements of temporal and polarization correlations measurements of multi-color photons emitted from cw optically excited single semiconductor quantum dots. We show that there are tunable intensity and polarization correlations among photons emitted at the same, and at different wavelengths due to the recombination of electron-hole pairs from different collective many-carrier quantum states confined in the dots. The observed polarization correlations between the emitted photons are qualitatively explained in terms of long electronic spin memory.