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Fano-Resonances in High Index Dielectric Nanowires for Directional Scattering

Abstract : High refractive index dielectric nanostructures provide original optical properties thanks to the occurrence of size- and shape-dependent optical resonance modes. These modes commonly present a spectral overlap of broad, low-order modes (\textit{e.g}. dipolar modes) and much narrower, higher-order modes. The latter are usually characterized by a rapidly varying frequency-dependent phase, which - in superposition with the lower order mode of approximately constant phase - leads to typical spectral features known as Fano resonances. Interestingly, such Fano resonances occur in dielectric nanostructures of the simplest shapes. In spheroidal nanoparticles, interference between broad magnetic dipole and narrower electric dipole modes can be observed. In high aspect-ratio structures like nanowires, either the electric or the magnetic dipolar mode (depending on the illumination conditions) interferes with higher order multipole contributions of the same nature (electric or magnetic). Using the analytical Mie theory, we analyze the occurrence of Fano resonances in high-index dielectric nanowires and discuss their consequences like unidirectional scattering. By means of numerical simulations, we furthermore study the impact on those Fano resonances of the shape of the nanowire cross-sections as well as the coupling of two parallel nanowires. The presented results show that all-dielectric nanostructures, even of simple shapes, provide a reliable low-loss alternative to plasmonic nanoantennas.
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https://hal.archives-ouvertes.fr/hal-01850259
Contributor : Peter Wiecha <>
Submitted on : Friday, July 27, 2018 - 10:30:33 AM
Last modification on : Tuesday, February 16, 2021 - 3:33:33 AM

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  • HAL Id : hal-01850259, version 1
  • ARXIV : 1801.05601

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Peter Wiecha, Aurelien Cuche, Houssem Kallel, Gérard Colas Des Francs, Aurélie Lecestre, et al.. Fano-Resonances in High Index Dielectric Nanowires for Directional Scattering. Herausgeber: Kamenetskii, Eugene, Sadreev, Almas, Miroshnichenko, Andrey (Eds.). Fano Resonances in Optics and Microwaves: Physics and Applications, Springer, pp.283-310, 2018, 978-3-319-99730-8. ⟨hal-01850259⟩

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