Collective emission of Radiation by an ensemble of excited atoms or ions.

Superfluorescence is a phenomenon of quantum optics. It is the collective emission of fluorescence by an ensemble of excited atoms or ions. Initially, the atoms or ions are incoherently excited SO that there is no macroscopic dipole moment. The process starts slowly with spontaneous emission. The radiation field then couples the radiation phases of the different atoms, so that they become synchronized, and a collective emission releases the stored Energy as a superfluorescent pulse. The pulse maximum occurs after some delay and the pulse duration can be short compared with the upper-state Lifetime of a single atom. The maximum Intensity of the emitted Light scales with the square of the number of atoms.