title: Photon statistics in the cooperative spontaneous emission.
abstract: The second-order photon correlation function g((2))(tau) of photons emitted by a continuously pumped ensemble of N two-level systems coupled to a single-mode optical cavity well below the lasing threshold is investigated theoretically. A giant photon bunching is found for N < 10 emitters as the microscopic counterpart of spontaneous emission noise driven quasi-periodic superradiant pulse sequences in macroscopic systems of large numbers of emitters N >> 1. The phenomenon of giant photon bunching is preserved even for N = 2 and can be explained by the cooperative evolution via dark and bright two-atom states resulting into emission of superradiant photon pairs. The sensitivity of g((2)) to microscopic dephasing processes and resonance frequency detuning opens the door for photon bunching spectroscopy.
authors.affiliation: Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA. temnov@mit.edu
authors.forename: Vasily V
authors.initials: VV
authors.lastname: Temnov
authors.forename: Ulrike
authors.initials: U
authors.lastname: Woggon