TE, TM modes photorefractive surface waves and their coupling

The nonlinear equations of photorefractive surface waves (PR SWs) with diffusion mechanism are established and calculated numerically for both TE mode and TM mode and their coupling for the first time. The characteristics of TE mode and TM mode are analyzed, such as propagation constants, spatial distribution, penetration depths etc. For relative larger propagation constant, most of the surface wave energy is concentrated on the Ax component of TM mode, and the penetration depth of Ay of TE mode is always larger than that of Ax of TM mode because electro-optical coefficient r13 is always smaller than r33 in general PRC. As a result, the energy of the PR SW is better confined near the surface for TM mode than that for TE mode. When both TE and TM modes PR SWs are present, they will be coupled drastically and the Ax component of TM mode and Ay component of TE mode resonate in the volume of PR medium. As a result, the PR SWs cannot remain decay, and the light energy can not be confined near the surface steadily and the modes are destroyed. The results provide the theoretical instructions and are very significant to generate steady and high density PR SW in practice.