Efficient unidirectional ridge excitation of surface plasmons

I P. Radko, Institute of Sensors, Signals and Electrotechnics, University of Southern Denmark
S I. Bozhevolnyi, Institute of Sensors, Signals and Electrotechnics, University of Southern Denmark
G Brucoli, Instituto de Ciencia de Materiales de Arag ´ on and Departamento de F´ısica de la Materia Condensada
L Mart´ın-Moreno, Instituto de Ciencia de Materiales de Arag ´ on and Departamento de F´ısica de la Materia Condensada
F J. Garc´ıa-Vidal, Departamento de F´ısica Te ´ orica de la Materia Condensada, Universidad Aut ´ onoma de Madrid
A Boltasseva, Birck Nanotechnology Center, Purdue University

Abstract

Using leakage-radiation microscopy, we characterize the efficiency of unidirectional surface-plasmon excitation with periodic (800 nm) arrays of 130-nm-high and 330-nm-wide gold ridges on a thin gold film illuminated with a focused (5-mu m-wide) laser beam. We demonstrate that, at the resonant wavelength of 816 nm, the excitation efficiency of > 0.4 can be obtained with >= 5 ridges by adjusting the beam position. Conducting numerical simulations, we account for the experimental results and calculate the electric-field enhancement achieved near the gold surface.

Discipline(s)

Nanoscience and Nanotechnology