Pérez García, Victor M.. 

The propagation of probe and coupling optical beams through a four-level coherent media is modeled by two coupled nonlinear Schrödinger equations. The nonlinear susceptibilities exhibited by the four-level media are calculated in the nonperturbative regime, i.e., considering the probe and coupling fields as having comparable amplitudes. We address the existence and stability of vector solitons build by the probe and coupling beams in the coupled nonlinear Schrödinger equations