SUCCESSIVE UPTAPERING AND STATIONARY SELF-TRAPPED PROPAGATION OF A LASER-BEAM IN A SATURATING NONLINEAR MEDIUM

A steady-state analysis of Gaussian laser beam in a nonlinear medium h as been presented. It is shown that an oscillatory self-guided beam (w hose width is oscillating with the propagation distance) in a saturabl e nonlinear medium can be uptapered by material gain. Moreover, the pr esent investigation suggests that under certain conditions it is possi ble to obtain a stationary self-guided beam (planar wavefront) in a no nabsorbing medium from an initially oscillatory (nonplanar wavefront) beam in a nonabsorbing medium by uptapering it in a gain medium.