Finite bandwidth excitation effect on the proton correlations in two-atom resonance fluorescence

Abstract

The influence of finite laser bandwidth excitation on the equal-time intensity correlation function of the electric field radiated by a system of two interacting atoms in the process of resonance fluoresence RF is discussed. It is shown that laser fluctuations reduce photon antibunching if detuning of the laser field from atomic resonance and dipole-dipole interaction between the atoms cancel out mutually. However, if the driving field is near resonance with the single-atom transition frequency, the inverse effect occurs: photon antibunching increases with increasing laser bandwidth ⌜, and attains its maximal value for moderate ⌜. Moreover, in this case, the maximum of photon antibunching is dependent on the intensity of the driving field. As the latter increases, this maximum shifts towards greater ⌜. For very large ⌜ (⌜ ⋙ 1) and very weak driving field, the intensity correlation function is always lower than unity, but for a strong driving field is equal to unity irrespective of the interatomic interaction, detuning and laser bandwidth.