Omaghali, Ndubuisi Emmanuel Jude (2013) Nanowire Dimer Metamaterial: Design, Fabrication and Optical Characterization. [Tesi di dottorato]

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Item Type: Tesi di dottorato
Resource language: English
Title: Nanowire Dimer Metamaterial: Design, Fabrication and Optical Characterization
Omaghali, Ndubuisi Emmanuel
Date: 2 April 2013
Number of Pages: 90
Institution: Università degli Studi di Napoli Federico II
Department: Fisica
Scuola di dottorato: Ingegneria industriale
Dottorato: Tecnologie innovative per materiali, sensori ed imaging
Ciclo di dottorato: 25
Coordinatore del Corso di dottorato:
Date: 2 April 2013
Number of Pages: 90
Keywords: Dimer, Metamaterial, Fano resonance, dark modes, ellipsometry, sensor
Settori scientifico-disciplinari del MIUR: Area 02 - Scienze fisiche > FIS/03 - Fisica della materia
Aree tematiche (7° programma Quadro): NANOSCIENZE, NANOTECNOLOGIE, MATERIALE E PRODUZIONE > Nanoscienze e Nanotecnologie
Date Deposited: 11 Apr 2013 10:32
Last Modified: 10 Jul 2014 09:06

Collection description

In this work we report on the electromagnetic resonances excited in a planar metamaterial consisting of pairs of gold bars(dimers) arrayed on a dielectric substrate. In the case of equal bar lengths, bright resonance modes can be easily excited, which couple strongly to free space and posses a low Q-factor. The introduction of bar length asymmetry induces the excitation of the so-called dark modes which couple very weakly to free space and show high Q-factors. The interaction of the dark and bright resonant modes results in a Fano type profile of the resonance. With increasing length asymmetry, coupling of the dark modes to free space is increased, resulting in a lowered Q-factor. We discuss the dependence of both the dark and bright modes on the dimer geometry and refractive index of the metamaterial environment, in order to optimize the structure for a potential application as an optical sensor. Effective material parameters were obtained from spectroscopic ellipsometry study of the metamaterial on a glass substrate and their physical meaning and applicability are discussed. Experimental results show good agreement with simulation.


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