Observation of Photon Antibunching in Phase-Matched Multiatom Resonance Fluorescence

Abstract
We report on the observation of photon antibunching in the resonance fluorescence field radiated by a many-atom source. The crucial feature of our experiment is the achievement of a phasematching configuration similar to that of four-wave mixing. The antibunching term results from a constructive interference of contributions from the N atoms and thus scales as N2.