We report the experimental observation of a polarization kink or domain wall soliton by mixing two intense counterpropagating laser beams in a nonlinear isotropic dielectric. This soliton represents the switching of the state of polarization of light between two domains where both waves are circularly polarized and corotating. Good agreement is obtained with the theoretical description of the effect.

• Received 5 February 1998

DOI:https://doi.org/10.1103/PhysRevLett.81.1409