Non-degenerated nonclassical photon pairs in a hot atomic ensemble.

We experimentally demonstrate the generation of non-degenerate nonclassical paired photons in a hot atomic ensemble using off-axis four-wave mixing. The time-resolved second-order correlated function between the Stokes photon and the anti-Stokes photon is given. The two-photon correlation between the photons obtained in this experiment is 1.87+/- 0.04, which leads to the violation of Cauchy-Schwarz inequality by a factor of 1.69+/- 0.14.