Non-Classical Correlated Photon Pairs Generation via Cascade Transition of 5S1/2-5P3/2-5D5/2 in a Hot SSRb Atomic Vapor

We experimentally prepare the non-classical correlated photon pairs at the wavelengths of 780 and 776 mn via the cascade transition of 5S1/2 5P3/2-5D5/2 in a hot SSRb atomic ensemble. By measuring the function of cross-correlation and auto-correlation of photons, a violation of Cauehy Schwarz inequality by a factor of 283 is obtained, which clearly indicates a strong non-classicM correlation between the generated photons. We also find that noise photons scattered from pump lasers have a strong effect on the Cauchy-Schwarz inequality factor by changing the intensity of the pump laser, the experimental results are consistent with the theoretical predictions.