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 |
| Creators: | Creators Email Omaghali, Ndubuisi Emmanuel Jude omaghali@na.infn.it |
| 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: | nome email Lanotte, Luciano lanotte@na.infn.it |
| Tutor: | nome email Abbate, Giancarlo giancarlo.abbate@na.infn.it Tkachenko, Vladimir tkachenko@na.infn.it Andreone, Antonello andreone@unina.it |
| 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 |
| URI: | http://www.fedoa.unina.it/id/eprint/9550 |
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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