Frequency dependent power efficiency of a nanostructured surface plasmon coupler



Surface plasmon (SP) excitation on an extended thin metal film via a miniature nanoparticle-enhanced grating coupler is studied experimentally using leakage radiation spectroscopy. A universally applicable method for determining the efficiency of free-space SP excitation is developed, and the efficiency of the coupler is determined. Two distinct grating excitation modes are observed, as well as a particle-mediated excitation mode. The maximum observed coupling efficiency of the structure was approximately 3.5% at 615 nm and 670 nm, corresponding to the two grating modes of the structure. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)