Light emission through a corrugated metal film: The role of cross-coupled surface plasmon polaritons

We examine the phenomenon of light emission through a thin metal film that takes place via surface plasmon polaritons. Surface plasmon polariton cross coupling has recently been invoked to explain sharp features observed in the angle dependent emission spectra obtained from surface-emitting (through cathode) organic light-emitting diode structures. We investigated whether such a cross-coupling process is needed to explain such observations. We undertook measurements on samples for a variety of metal film thicknesses. Our results are consistent with the mechanism of surface plasmon polariton cross coupling but also show that the processes underlying the emission from such structures can be rather subtle.