Spatial interplay of two four-wave mixing images

We investigate the interplay between the two components of the four-wave mixing (FWM) beams in a ladder-type three-level atomic system. The interplay, including the shift and splitting of the two FWM beams and their intensity modulation, depends on the frequency detuning and the angles as well as the powers of the pump fields. The x-directional splitting due to the cross-phase modulation and y-directional splitting because of electromagnetically induced gratings of FWM beams are investigated. Both the theoretical and experimental results exhibit that the spatial separation and the number of the FWM signals can be well controlled by additional dressing laser beams. Such studies not only can be very useful in better understanding the formation of spatial solitons but also have potential applications in signal processing.