Crystal Optics of Surface Polaritons in Anisotropic Crystals

A general theory of the surface polariton states in anisotropic crystals at arbitrary orientation of crystal axes with respect to the surface is developed. General formulae describing dispersive curves and polarization of surface polaritons (SP) are obtained. It is shown that (contrary to the case of SP in isotropic crystals in which they are H-waves) the anisotropic SP polarization is in general of mixed (EH-) type, and the spatial decay of SP is nonexponential. Attenuated total reflection spectra of anisotropic SP's in a crystal α-LiIO3 are investigated. Experimental and theoretical results are in a good agreement.