Enhancement and Suppression in Four-Wave Mixing Processes

Abstract

Interplays between four-wave mixing (FWM) processes in multi-dressed multilevel atomic systems are quite interesting. The generated FWM signal can be selectively enhanced and suppressed via an EIT window. The evolution of dressed effects can be from pure enhancement into pure suppression in the degenerate-FWM processes. On the other hand, since the atomic transitions are very sensitive to the polarization states of the pump and probe beams in multi-Zeeman sub-level atomic systems, the enhancement and suppression of FWM signals are also dependent on the polarization states of the laser beams on real atomic systems (with Zeeman sub-levels). The FWM processes in a multi-Zeeman level atomic system can be enhanced and suppressed by changing the polarization of the pump and probe beams. Different polarization states of the pump and probe beams will act on different transition pathways among the multi-Zeeman levels with different transition strengths, which affect the FWM efficiencies. Understanding the efficiencies of nonlinear wave-mixing processes via laser intensities, frequency detunings, and polarization states in multi-level atomic systems can be very useful in controlling them for various applications, such as coherent quantum control, nonlinear optical spectroscopy, precision measurements, and quantum information processing.