Plasmon transmissivity and reflectivity of narrow grooves in a silver film

Surface plasmon (SP) reflectivity and transmissivity of narrow grooves in silver films are studied. The SP source is the probe of a scanning near-field optical microscope. Locally detected leakage radiation from the SP provides detailed information on the paths of SP propagation, in particular the influence of perturbations. Global detection provides representative average data on the SP properties of a given metal film and its structures. A groove of 200 nm width, for instance, reflects/transmits about 15%/80% of 'blue–green' SP radiation at normal incidence.