title: Solitary waves in liquid crystalline waveguides.
abstract: Recently, it has been shown experimentally that the nonlinearity in nematic liquid crystals can govern spatial solitons in both waveguide and bulk geometry. Such solitons require a few milliwatts of light power and can be controlled by the state of light polarization or by an external electrical field. In this paper a detailed theoretical analysis of optical solitary waves in nematic liquid crystal waveguides is presented. The self-focusing is induced by reorientation nonlinearity in the homeotropically aligned nematic layer. This configuration corresponds to the experimental setup in which we previously observed such solitary waves. The theoretical results presented in this paper correlate exactly with the experiments.