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Chalcogenide-based phase-change metamaterials

Chalcogenide-based phase-change metamaterials
Chalcogenide-based phase-change metamaterials
Phase-change metamaterials combine the sharp resonant dispersions afforded by metamaterials with the optical switching characteristics of phase-change chalcogenides to create a high-contrast, non-volatile planar optical modulator. Spectroscopic ellipsometry was used to accurately determine the highly-contrasting complex dielectric functions of the amorphous and crystalline states of GST, an amorphous chalcogenide. This data was then used to model a phase-change metamaterial hybrid device in both phases,which showed a large wavelength shift in resonant spectral features on crystallisation of the chalcogenide layer. Femtosecond pulse-induced crystallisation and amorphisation of thin films of GST was shown to be possible, and the crystalline fraction in the material was shown to be continuously tunable. Femtosecond pulses were then used to reversibly switch a phase-change metamaterial device to modulate the trapped mode resonance. Modelling of an all-dielectric phase-change metamaterial structure indicated that larger optical modulation may be realised by changing the phase of the resonant structure itself.
Maddock, Jonathan
7a64744f-cd7c-4c6a-b584-af266dd08da5
Maddock, Jonathan
7a64744f-cd7c-4c6a-b584-af266dd08da5
Hewak, Daniel
87c80070-c101-4f7a-914f-4cc3131e3db0

Maddock, Jonathan (2014) Chalcogenide-based phase-change metamaterials. University of Southampton, Faculty of Physical Sciences and Engineering, Masters Thesis, 79pp.

Record type: Thesis (Masters)

Abstract

Phase-change metamaterials combine the sharp resonant dispersions afforded by metamaterials with the optical switching characteristics of phase-change chalcogenides to create a high-contrast, non-volatile planar optical modulator. Spectroscopic ellipsometry was used to accurately determine the highly-contrasting complex dielectric functions of the amorphous and crystalline states of GST, an amorphous chalcogenide. This data was then used to model a phase-change metamaterial hybrid device in both phases,which showed a large wavelength shift in resonant spectral features on crystallisation of the chalcogenide layer. Femtosecond pulse-induced crystallisation and amorphisation of thin films of GST was shown to be possible, and the crystalline fraction in the material was shown to be continuously tunable. Femtosecond pulses were then used to reversibly switch a phase-change metamaterial device to modulate the trapped mode resonance. Modelling of an all-dielectric phase-change metamaterial structure indicated that larger optical modulation may be realised by changing the phase of the resonant structure itself.

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More information

Published date: August 2014
Organisations: University of Southampton, Optoelectronics Research Centre

Identifiers

Local EPrints ID: 372467
URI: http://eprints.soton.ac.uk/id/eprint/372467
PURE UUID: 1544010a-6d9d-4a60-8dfa-5aadd1a4fb22
ORCID for Daniel Hewak: ORCID iD orcid.org/0000-0002-2093-5773

Catalogue record

Date deposited: 22 Dec 2014 14:50
Last modified: 06 Jun 2018 13:08

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Contributors

Author: Jonathan Maddock
Thesis advisor: Daniel Hewak ORCID iD

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