Plasmonic graded-chains as deep-subwavelength light concentrators

NATALIA ESTEVES-LÓPEZ; HORACIO M. PASTAWSKI; RAÚL A. BUSTOS MARÚN

IOP PUBLISHING LTD

Lugar: Londres; Año: 2015 vol. 27 p. 125301 - 125301

e have studied the plasmonic properties of aperiodic arrays of identical nanoparticles (NPs) formed by two opposite and equal graded-chains (a chain where interactions change gradually). We found that these arrays concentrate the external electromagnetic fields even in the long wavelength limit. The phenomenon was understood by identifying the system with an effective cavity where plasmonics excitations are trapped between effective band edges, resulting from the change of passband with the NP's position. Dependence of excitation concentration on several system parameters was also assessed. This includes different gradings as well as NP couplings, damping, and resonant frequencies. In the spirit of the scaling laws in condensed matter physics, we developed a theory that allows us to rationalize all these system parameters into universal curves. The theory is quite general and can also be used in many other situations (different arrays for example). Addition