Abstract: The Maxwell＇s equations are solved on the metallic surface, and the reason why light can not excite the surface plasmons directly is explained. Otto configuration and Kretschmann configuration are introduced, with which the surface plasmons could be excited by the evanescent wave of incident light, and in these two configurations the relationship of dielectric functions of prism and the medium and the requirement of middle layer thickness are presented.

Key words: metallic surface plasmon, attenuated total reflectivity, Otto configuration, Kretschmann configuration