Superfluorescence and cooperative frequency shift

We report on a first-principles demonstration of the superfluorescence effect in a large system. Under proper conditions, a system of two-level atoms, confined to a pencil-shaped volume, and initially prepared in an uncorrelated excited state, goes through a nonexponential cooperative decay, giving rise to a superfluorescence burst. Radiation is all confined in two diffraction patterns and the central frequency presents a time-dependent shift (chirping). © 1974 The American Physical Society.