Characteristics of a four-wave radiation converter in a multimode waveguide with resonant nonlinearity

Quality of the wavefront reversal by a four-wave radiation converter in a parabolic waveguide with resonant nonlinearity have been analyzed using the point spread function. Medium with resonant nonlinearity have been modeled by an ensemble of particles described by a two-level energy scheme. It has been shown that over time, the half-width of the point spread function module decreases, reaching a stationary value, the magnitude of which is determined by the first pump wave intensity in the case of a long waveguide. A decrease in the pump radius at low intensity of the first pump wave leads to a decrease in the half-width of the point spread function modulus (the quality of the wavefront reversal improves), and at high intensity leads to an increase in the half-width of the point spread function modulus (the quality of the wavefront reversal deteriorates) in the stationary case with distribution on the back waveguide face depending on the transverse coordinate of the second pump wave amplitude of the according to the Gaussian law.