Induced focusing of two laser beams in cubic quintic nonlinear media

This paper presents an investigation of induced focusing of two laser beams (i.e., a pump beam and another probe beam) in a medium possessing cubic quintic nonlinearity. Third and fifth order nonlinear susceptibilities in presence of two interacting waves have been evaluated. These susceptibilities are then employed to derive two coupled nonlinear Schrodinger equations. Variational formalism has been employed to derive relevant equations which govern different characteristics of propagating beams. Extensive numerical simulation has been performed to investigate the influence of the pump beam on the propagation characteristics of the probe beam. Among several important findings. most noteworthy one is that a very weak probe beam can be guided and focused with a pump beam even if its power is well below threshold Value of focusing of the pump beam alone. It has been found that induced focusing of the probe beam is more effective when its wavelength is smaller and initial beam width larger than the corresponding quantities of the pump. The roles of fifth order nonlinear coefficient on induced focusing have been investigated. Particularly. it has been established that even an initially defOCUsing pump can focus a very weak probe.