Resonance anomalies in the light intensity reflected at silver gratings with dielectric coatings

The intensity of p-polarized light specularly reflected at silver gratings with LiF coatings of varying thickness was investigated. The influence of the groove depth of the modulated silver surface and the thickness of the LiF coating on the resonance anomalies in the reflected light intensity was determined experimentally. The characteristic behaviour of these anomalies is explained by the properties of the optical eigen-oscillations (surface plasma oscillations and guided light modes) in the layer system.