A ray model for an evanescent plane wave has been introduced to describe the property of propagation. It is found that an evanescent wave undergoes an amplitude jump during refraction and reflection on a plane interface. TE surface modes guided by a single interface and a slab waveguide containing left-handed materials are then analyzed by using a ray picture. In a slab waveguide with left-handed material cover or substrate, the odd surface mode does not exist, but there exist two even surface modes. We derive dispersion relations of TE surface guided modes according to physical principles, thus describing the surface modes purely on an intuitive and simple basis. Besides, guiding mechanics and conditions are compared between oscillating and surface guided modes. (C) 2008 Optical Society of America.
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