Attenuation of long-range surface polaritons in a thin metallic slab with a dielectric coating

Abstract

Long-wavelength TM electromagnetic modes of a bilayer system consisting of a thin metallic slab in contact with a dielectric slab are analyzed in detail. The theory is applied to the discussion of the attenuation of infrared surface polaritons (SP) guided by a coated thin metallic slab. Both the dependence of SP damping on the SP frequency and on the thickness of each slab is considered. It is shown that, besides an overall increase of SP damping (compared with the damping of SP in a bare metallic slab), at characteristic frequencies of the dielectric overlayer resonant absorption of SP takes place due to conversion of the SP energy into the energy of mechanical vibrations in the dielectric. These effects are most prominent for long-range antisymmetric SP in a thin metallic slab which makes them very suitable as a probe for coatings on metals.