Frequency dependent power efficiency of a nanostructured surface plasmon coupler

1 Introduction The field of integrated surface plas-mon (SP) nanophotonics continues to develop rapidly due to the considerable advantages of SPs over traditional integrated photonic structures. The high degree of confinement of SPs at a single interface allows for various easily-fabricated single-interface waveguide designs [1 – 4]. Di-electric loaded SP waveguides [1] represent a promising approach, allowing for the development of SP based optical interconnects on standard silicon integrated circuits. To communicate with densely integrated plasmonic components , there is a need for a compact structure for coupling to SPs, and a corresponding need for a method for determining the coupling efficiency of any such structures. Here we study a nanoparticle enhanced grating coupler for exciting SPs on a nearby metal film. We use a broadly applicable method to determine the absolute wavelength dependent coupling efficiency of the miniature coupler, and demonstrate the presence of both grating-mediated and particle resonance mediated SP excitation.