Electromagnetically induced diffraction in sodium vapor

Multi-wave-mixing-induced nonlinear modulation of diffraction peaks in an opto-atomic grating

We propose an atomic model in close-loop configuration, which exhibits controllable symmetric and asymmetric evolution of significantly enhanced diffraction peaks of the weak probe beam in an opto-atomic grating at far-field regime. Such results are obtained by the linear and nonlinear modulation of the intensities of the diffraction peaks as a result of multi-wave-mixing-induced modification of spatially modulated coherence in a closed four-level atomic system. Novelty of the results lies in predicting the diffraction pattern with uniform peak height due to the dominance of the amplitude part of the grating-transfer-function at the condition of exact atom-field resonance, which is unique to the present model. Efficacy of the present scheme is to apply it in producing nonlinear light generated by four-wave-mixing-induced control of spatially modulated coherence effect. The work also finds its importance for its applicability in the field of all-optical devices.

Spatial interference between four- and six-wave mixing signals

We experimentally demonstrate spatial interference between simultaneously generated four-wave mixing (FWM) and six-wave mixing (SWM) signals in a multilevel atomic system. By tuning the relative phase between the FWM and SWM processes the relative strengths between these two high-order nonlinear optical processes can be investigated.

Four-wave parametric oscillation in sodium vapor by electromagnetically induced diffraction

We have observed a novel type of parametric oscillation in sodium atomic vapor where four off-axis signal waves simultaneously build up under resonant and counterpropagating pump beams with elliptical beam profiles. The four waves, two of them Stokes shifted and the other two anti-Stokes shifted, have similar output powers of up to 10 mW with a conversion efficiency of 30% and are parametrically coupled by electromagnetically induced diffraction.