Higher-Order Photon Bunching in a Semiconductor Microcavity

A Multiple Photon Pileup The field of quantum optics began with the observation that two independent photons emitted from a thermal source tend to bunch together. The same is true for any number of bosons, but how do the statistics and correlations evolve experimentally as the number increases? Aβmann et al. (p. 297) have developed a streak-camera technique that can distinguish the photon number and measure the higher-order correlations between the photons at the detector. The results confirm the predicted “n factorial” dependence, showing that the tendency to bunch gets stronger as the number of independent photons is increased. The tendency for photons to bunch gets stronger as their number increases. Quantum mechanically indistinguishable particles such as photons may show collective behavior. Therefore, an appropriate description of a light field must consider the properties of an assembly of photons instead of independent particles. We have studied multiphoton correlations up to fourth order in the single-mode emission of a semiconductor microcavity in the weak and strong coupling regimes. The counting statistics of single photons were recorded with picosecond time resolution, allowing quantitative measurement of the few-photon bunching inside light pulses. Our results show bunching behavior in the strong coupling case, which vanishes in the weak coupling regime as the cavity starts lasing. In particular, we verify the n factorial prediction for the zero-delay correlation function of n thermal light photons.