Self-trapped optical beams in liquids

The conditions under which an electromagnetic beam can produce its own dielectric waveguide and propagate without spreading are discussed for a model of the nonlinear dielectric response which includes the effects of saturation. The model assumes that the principal contribution to the nonlinear response arises from the reorientation of anisotropic molecules. For the lowest order "modes," the variation of the field amplitude over the cross section of the beam for various total powers in the beam is presented graphically. It is also shown that, for "cigar"-type axially symmetric molecules, there are two trapped beams possible which have no nodes, but which have the same total power.