Delayed four- and six-wave mixing in a coherently prepared atomic ensemble

Abstract

We report on the simultaneous observation, by delayed Bragg diffraction, of four- and six-wave mixing processes in a coherently prepared atomic ensemble consisting of cold cesium atoms. For each diffracted order, we observe different temporal pulse shapes and dependencies with the intensities of the exciting fields, evidencing the different mechanisms involved in each process. The various observations are well described by a simplified analytical theory, which considers the atomic system as an ensemble of three-level atoms in Λ configuration.

Nonlinear coupling between two Zeeman coherence gratings stored in cold atoms

“…The fact that the total energy extracted from the medium reaches a minimum value for comparable intensities of the grating writing beams, i.e., for I W 1 ≈ I W 2 , reflects the maximization of the contributions of higher-order processes. It is worth mentioning that a similar saturation behavior was observed previously in the generation of a pair of pulses from a single coherence grating [19,20]. However, in the present case the saturation is not induced by the reading beam but is rather stored as the nonlinear coupling between two coherence gratings.…”

“…This simple experimental configuration allowed us to demonstrate the nonlinear coupling between the two stored gratings and to describe its saturation dynamics in terms of the above-mentioned simplified LS picture. It is worth mentioning that cross-saturation effects in LS processes have been observed previously in the double reading of a stored grating and were explained as originating from the contribution of higher-order wave-mixing processes [19,20]. However, in the present case the saturation is induced in the writing process and is therefore stored in the atomic medium as multiple coupled Zeeman coherence gratings.…”

Bunching-induced optical nonlinearity and instability in cold atoms [Invited]

“…They can be used in quantum information networks as new sources of correlated pulse pairs and quantum memories [9] and for performing 3-bit quantum processing [10,11], for example. By controlling the relative contributions of the χ (3) and χ (5) NLO response, one can create novel states of light such as liquid light condensates [6] as well as use the interference of the resulting four-and six-wave mixing signals for high-precision measurements and nonlinear spectroscopy [12].…”

Giant parabolic nonlinearities at infrared in Λ-type three level multiple quantum wells

“…For example, materials that exhibit large fifth order susceptibility can lead to new phenomena such as liquid light condensates analogous to fluid droplets [26], transverse pattern and stable 2D-soliton formation including bistable solitons [27]. Materials with large fifth order susceptibility play important role in quantum information networks through enabling 3-qubit quantum processing [28,29], provides new sources of correlated pulse pairs [30] and act as quantum memories [30,31]. Fifth order susceptibility can also improve high precession measurements [24] and reduce phase noise for enhanced performance of interferometry [32].…”