Superluminal propagation of pulsed pseudo-thermal light in atomic vapor

We report an experimental demonstration of slow and superluminal propagation of pseudo-thermal (chaotic) light in the λ-type system of the 5S_1/2-5P_1/2 transition of ⁸⁷Rb atom. The slowed propagation of pulsed pseudo-thermal light was demonstrated in an electromagnetically-induced transparency medium while the superluminal propagation was demonstrated with the enhanced absorption scheme where the coupling field takes the form of a standing wave.We have also demonstrated that the photon number statistics of the pseudo-thermal light is preserved for both the subluminal and superluminal cases.