Dynamic control of four-wave-mixing enhancement in coherently driven four-level atoms

We analyze a four-wave mixing enhancement scheme based on a specific lifetime-broadened four-level atomic configuration. The enhancement can mainly be controlled through the time-dependent propagation dynamics of the applied pulse fields, but it is also found to depend on the sample density and spontaneous emission of the levels involved. A systematic analysis, that illustrates how the applied pulses dynamics, density, and spontaneous emission affect the mixing conversion efficiency, is carried out, anticipating substantially large efficiencies for realistic atomic parameters and short weak laser pulses.