Generation of three polarization-correlated photons from a single semiconductor quantum dot

We performed polarization-resolved cross-correlation measurements on a radiative cascade of a charged tri-exciton in a single quantum dot. Photoluminescence spectra showed rich peaks arising from the formation of charged excitonic complexes. The energy structure in the cascade transition of a charged tri-exciton was explained by the exchange interaction. By using one transition pathway of the cascade, whose intermediate states form spin-triplet states, we succeeded in generating three polarization-correlated photons with circular polarization