Study of resonant modes of a periodic metallic array near a dielectric interface: evanescent-to-propagating coupling via surface plasmon excitation

DIANA CARINA SKIGIN; MARCELO LESTER,

JOURNAL OF OPTICS. A, PURE AND APPLIED OPTICS (PRINT)

Institute of Physics Publishing

Año: 2006 vol. 8 p. 259 - 267

1464-4258

The structural modes of a 2D periodic array of metallic cylinders near adielectric interface are studied, for large and small wavelength-to-periodratios. We show that there are two clearly distinguished kinds of resonances:waveguide modes of the gap between the array and the interface, andeigenmode excitations (plasmons). While waveguide modes are present forboth polarizations, surface plasmon polaritons (SPPs) only occur for ppolarization, and, under particular conditions, this mechanism can produce anefficient coupling (about 60%) between the incident evanescent wave and theeigenmodes supported by the structure, which produces an enhancedtransmitted propagating order. The response of the structure is analysed indetail by varying its relevant parameters, paying particular attention to theinterplay between SPPs and Rayleigh anomalies, and its effect on the gratingresponse.