Numerical optimization of a grating coupler for the efficient excitation of surface plasmons at an Ag-SiO_2 interface

The efficient generation of surface plasmons from free-space optical waves is still an open problem in the field. Here we present a methodology and optimized design for a grating coupler. The photoexcitation of surface plasmons at an Ag-SiO2 interface is numerically demonstrated to yield a 50% coupling efficiency from a Gaussian beam into surface plasmon voltages and currents.