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

Abstract

The structural modes of a 2D periodic array of metallic cylinders near a dielectric interface are studied, for large and small wavelength-to-period ratios. We show that there are two clearly distinguished kinds of resonances: waveguide modes of the gap between the array and the interface, and eigenmode excitations (plasmons). While waveguide modes are present for both polarizations, surface plasmon polaritons (SPPs) only occur for p polarization, and, under particular conditions, this mechanism can produce an efficient coupling (about 60%) between the incident evanescent wave and the eigenmodes supported by the structure, which produces an enhanced transmitted propagating order. The response of the structure is analysed in detail by varying its relevant parameters, paying particular attention to the interplay between SPPs and Rayleigh anomalies, and its effect on the grating response.

Physical characteristics of localized surface plasmons resulting from nano-scale structured multi-layer thin films deposited on D-shaped optical fiber

“…Examples of the effects of surface topology on the spectral behavior of plasmons can easily be found in the literature [10]. The optical properties and characteristics of structured thin film can be comprehensively tuned by nano-engineering the structure parameters, such as using periodically arranged nanopores or microporous and nanoporous metal structures [10,[17][18][19].…”

Generation and performance of localised surface plasmons utilising nano-scale structured multi-layered thin films deposited upon D-shaped optical fiber

“…Examples of the effects of surface topology on the spectral behaviour of plasmons can easily be found in the literature [11]. The optical properties and characteristics of structured thin film can be comprehensively tuned by nano-engineering the structure parameters, such as using periodically arranged nanopores or microporous and nanoporous metal structures [11,12,13,14].…”

Highly sensitive, localized surface plasmon resonance fiber device for environmental sensing, based upon a structured bi-metal array of nano-wires

“…Surface plasmons can generally be categorized as long range surface plasmons (LRSP) [6], short range surface plasmons (SRSP) [6], and localized surface plasmons (LSPs) [7]. The different types of SPR are all generated at a metal/dielectric interface; any differences in optical and physical properties principally arise from the geometrical properties of that interface [8,9]. Recently there has been interest in the generation of LSP from various surface topologies, including structured thin films.…”

“…The resonant condition for the LSP that needs to be satisfied for a lattice structure is given in [7]. An added complexity to the spectral behavior of LSP is the many physical dependencies, such as the size, topology, and geometries of the plasmon-supporting nano-structures [4,8]. The optical properties and characteristics of structured thin films can be comprehensively tuned by nanoengineering the structure parameters [8,9].…”

“…An added complexity to the spectral behavior of LSP is the many physical dependencies, such as the size, topology, and geometries of the plasmon-supporting nano-structures [4,8]. The optical properties and characteristics of structured thin films can be comprehensively tuned by nanoengineering the structure parameters [8,9]. We report on a novel LSP fiber sensor based on an ultraviolet laser inscribed surface relief structure that resembles an array of nano-wires in a multilayered thin film, deposited on the flat side of a lapped D-shaped fiber.…”