Surface plasmon-polariton mediated light emission through thin metal films

The emission of light by sources in close proximity to a thin metallic film is dominated by surface plasmon-polariton modes supported by that film. We explore the nature of the modes and examine how the energy lost to such modes can be recovered. Both cross-coupled and coupled SPPs are presented as a means of transferring energy across a thin metal film. These modes are then scattered and thereby coupled to light by a wavelength scale grating type microstructure. We show that the photoluminescence emission from a structure containing a microstructured thin metal film that supports coupled SPPs is over 50 times greater than that from a similar planar structure. Similar strong photoluminescence emission is also exhibited by a sample that contains a planar metal film coated with a microstructured dielectric overlayer.