Interference bunching and antibunching of coherent and atomic radiation fields

When a coherent field is combined with the phase-matched output of an atomic ensemble, the second-order correlation function of the total field can exhibit superbunching or antibunching. Homodyning the reference field with the atomic emission can amplify the nonclassical characteristics of the atomic emission. A theoretical description of these phenomena is presented. It is pointed out that, even if the number of excitations in the ensemble is much less than unity, truncating a factorized state to have at most two excitations can lead to errors in calculating the second-order correlation function. We also include the effects of dephasing produced by Rydberg -Rydberg interactions and show how they modify the bunching and antibunching that occur in the absence of atom-atom interactions. It is shown that the particle separation probability distribution and the joint particle separation probability distribution play critical roles in determining the effects of dephasing.