de Almeida, Alexandre A. C. — Generation of correlated forward four-wave mixing signals with cold atoms

We report preliminary results on the generation of two correlated  Forward Four-Wave Mixing (FFWM) signals using cold rubidium atoms. To induce the FFWM process, we use two almost copropagating beams, with linear and orthogonal polarization. We calculate the time-delay intensity correlation function between all four fields to detect correlation and anticorrelation. In addition, the spectral lineshape of the FFWM signals presents an interesting feature. If one scans the frequency of both input beams simultaneously, the spectra will present a dip around the resonance due to the coherent population trapping. We use a simple three-level lambda system and solve the Bloch equations to model this feature.