Optimum parameters for focusing of optical beams in self-defocusing nonlinear media

In this paper, a thorough discussion is given about the focusing of optical beams due to the cross-phase modulation in self-defocusing nonlinear media. We discuss the effect on the focusing of the signal beams for the three initial parameters: the amplitude of the pump beam, the separation between the pump and the signal beam centers, and the wavelength ratio of the two beams, Our numerical results show that two of the three parameters (separation between the two beam centers and the wavelength ratio of the two beams) have optimum values, respectively, which result in the strongest focusing of the signal beam. Our results can be used to design experiments to obtain the best results of focusing.