Photon Statistics in Resonance Fluorescence with Finite Bandwidth Excitation

Abstract

The phenomenon of antibunching in time exhibited by photons emitted by a driven two-level atom is an explicit feature of a quantized electromagnetic field.^1,2 Antibunching implies that the fluorescent photons obey sub-Poissonian statistics at least for sufficiently small counting interval T. This implies that the probability p(n,t,T) that n photons are emitted in a given time interval (t, t + T) is narrower than a Poisson distribution with the same mean n. For large times T, however, this need not be the case. Indeed for large counting times T the distribution p(n,t,T) may be superPoissonian in the transient regime, although the fluorescent photons still exhibit antibunching.