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Insights into directional scattering: from coupled dipoles to asymmetric dimer nanoantennas

Abass, Aimi; Gutsche, Philipp; Maes, Bjorn; Rockstuhl, Carsten; Martins, Emiliano R.

Abstract (englisch): Strong and directionally specific forward scattering from optical nanoantennas is of utmost importance for various applications in the broader context of photovoltaics and integrated light sources. Here, we outline a simple yet powerful design principle to perceive a nanoantenna that provides directional scattering into a higher index substrate based on the interference of multiple electric dipoles. A structural implementation of the electric dipole distribution is possible using plasmonic nanoparticles with a fairly simple geometry, i.e. two coupled rectangular nanoparticles, forming a dimer, on top of a substrate. The key to achieve directionality is to choose a sufficiently large size for the nanoparticles. This promotes the excitation of vertical electric dipole moments due to the bi-anisotropy of the nanoantenna. In turn, asymmetric scattering is obtained by ensuring the appropriate phase relation between the vertical electric dipole moments. The scattering strength and angular spread for an optimized nanoantenna can be shown to be broadband and robust against changes in the incidence angle. The scattering directionality is maintained even for an array configuration of the dimer. It only requires the preferred scattering direction of the isolated nanoantenna not to be prohibited by interference

Zugehörige Institution(en) am KIT Institut für Nanotechnologie (INT)
Institut für Theoretische Festkörperphysik (TFP)
Publikationstyp Zeitschriftenaufsatz
Jahr 2016
Sprache Englisch
Identifikator DOI: 10.1364/OE.24.019638
ISSN: 1094-4087
URN: urn:nbn:de:swb:90-594647
KITopen ID: 1000059464
HGF-Programm 43.23.01; LK 01
Erschienen in Optics express
Band 24
Heft 17
Seiten 19638-19650
Bemerkung zur Veröffentlichung Gefördert durch den KIT-Publikationsfonds
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