Field-field and photon-photon correlations of light scattered by two remote two-level InAs quantum dots on the same substrate.

We report the measurement of field-field and photon-photon correlations of light scattered by two InAs quantum dots separated by ≈40  μm. Near 4 K a large fraction of photons can be scattered coherently by each quantum dot leading to one-photon interference at a beam splitter (visibility ≈20%). Simultaneously, two-photon interference is also observed (visibility ≈40%) due to the indistinguishability of photons scattered by the two different quantum emitters. We show how spectral diffusion accounts for the reduction in interference visibility through variations in photon flux.