IFEG   20353
INSTITUTO DE FISICA ENRIQUE GAVIOLA
Unidad Ejecutora - UE
artículos
Título:
Plasmonic graded-chains as deep-subwavelength light concentrators
Autor/es:
NATALIA ESTEVES-LÓPEZ; HORACIO M. PASTAWSKI; RAÚL A. BUSTOS MARÚN
Revista:
JOURNAL OF PHYSICS CONDENSED MATTER
Editorial:
IOP PUBLISHING LTD
Referencias:
Lugar: Londres; Año: 2015 vol. 27 p. 125301 - 125312
ISSN:
0953-8984
Resumen:
We 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). Additionally, we also provided an analytical solution, in
the tight-binding limit, for the plasmonic response of homogeneous
linear chains of NPs illuminated by a plane wave. Our results can find
applications in sensing, near field imaging, plasmon-enhanced
photodetectors, as well as to increase solar cell efficiency.