We demonstrate the existence of nonclassical correlations in the radiation of two atoms, that are coherently driven by a continuous laser source. The photon-photon correlations of the fluorescence light show a spatial interference pattern not present in a classical treatment. A feature of this phenomenon is that bunched and antibunched light is emitted in different spatial directions. The calculations are performed analytically. It is pointed out that the correlations are induced by state reduction due to the measurement process when the detection of the photons does not distinguish between the atoms. It is interesting to note that the phenomena show up even without any interatomic interaction.

• Received 11 July 2000

DOI:https://doi.org/10.1103/PhysRevA.64.063801