STABILIZATION OF TRANSVERSE SOLITARY WAVES BY A NONLOCAL RESPONSE OF THE NONLINEAR MEDIUM

Optical pumping of atomic vapors can lead to self-focusing of resonant laser beams. The saturation of the optical pumping process at low int ensity allows the study of transverse solitons in the form of self-tra pped laser beams, using low-power cw lasers. The long lifetime of the optically pumped atoms allows the atomic diffusion to transport the ex citation away from the interaction region. Numerical simulations show that the resulting nonlocal response of the medium represents an impor tant mechanism that stabilizes the self-trapped beam. The theoretical predictions are confirmed by experimental results from sodium vapor.