Frank Jahnke, Christopher Gies, Marc Assmann, Manfred Bayer, H.A.M. Leymann, Alexander Foerster,  Jan Wiersig, Christian Schneider, MartinKamp, Sven Hoefling.

Nature Communications (2016) 7, 11540

http://dx.doi.org/10.1038/ncomms11540

Light is often characterized only by its classical properties, like intensity or coherence. Whenlooking at its quantum properties, described by photon correlations, new information aboutthe state of the matter generating the radiation can be revealed. In particular the differencebetween independent and entangled emitters, which is at the heart of quantum mechanics,can be made visible in the photon statistics of the emitted light. The well-studiedphenomenon of superradiance occurs when quantum–mechanical correlations between theemitters are present. Notwithstanding, superradiance was previously demonstrated only interms of classical light properties. Here, we provide the missing link between quantumcorrelations of the active material and photon correlations in the emitted radiation. We usethe superradiance of quantum dots in a cavity-quantum electrodynamics laser to show adirect connection between superradiant pulse emission and distinctive changes in the photoncorrelation function. This directly demonstrates the importance of quantum–mechanicalcorrelations and their transfer between carriers and photons in novel optoelectronic devices.