Surface waves propagating along the interface between parabolic graded-index medium and photorefractive crystal with diffusion nonlinearity

Abstract

The new types of surface waves propagating along the interfaces between photorefractive crystal and parabolic graded-index medium are described theoretically. The optical parameters of contacting media are chosen that the depth of field localization is less than the thickness of the graded-index layer. Exact solutions to the boundary problem in different range of the effective refractive index are obtained. The surface waves attenuating with oscillations into the photorefractive crystal can propagate with arbitrary values of the effective refractive index and with its fixed values corresponding to the discrete spectrum. The effect of the optical characteristics of the crystals on field distribution is analyzed. The surface wave corresponding to the ground mode of the discrete spectrum monotonically attenuating on both sides of the interface is found. The angle of incidence need not be small to excite surface waves with a non-oscillating profile. The period of spatial oscillations must be greater than the field penetration depth into the photorefractive crystal to excite the surface waves monotonically attenuating in the depth of the crystal.