Waveguide modes with threshold nonlinearity

A three-layer structure consisting of a nonlinear optical medium with a stepwise change in the dielectric constant inside which there is a dielectric layer of finite thickness is considered. The surface waves of two types of symmetry with a special field structure can propagate along the layers. Domains of finite width with different optical properties in the border regions in a nonlinear medium are formed. The formation of domains, as well as the existence of surface waves, occurs at interlayer thicknesses not exceeding a certain critical value.