ABSORPTION AMPLIFICATION-INDUCED SELF-TAPERING AND UPTAPERING OF A LASER-BEAM IN A SATURABLE NONLINEAR MEDIUM - LARGE NONLINEARITY

We discuss the possibility of self-taping and uptapering of a self-gui ded Gaussian laser beam induced by absorption and gain when the beam p ropagates in a medium with large saturable nonlinearity. Conditions fo r self-tapering/uptapering for both the cases, i.e., for absorption an d gain, are discussed. The width of the tapered/uptapered beam depends on the rate of absorption and gain and on the length of the absorptio n and gain regions along the beam-propagation direction.