The experimental work undertook in this thesis looks to integrate technologies developed by the graphene and plasmonics communities, respectively, for the purpose of producing devices of enhanced qualities to those of similar utility that have previously been produced. Furthermore, where possible, we look to offer disruptive innovation, by utilising coupled properties that may offer unique possibilities for applications. A hybrid graphene-plasmonic waveguide modulator is fabricated and shown to operate successfully at a standard telecommunications frequency. Different plasmonic-waveguide designs — the basis for the modulator — were produced to probe the coupling between graphene and the surface plasmon-polariton modes. A mode excitable at the edge of the waveguide was found to offer the best modulation, with a modulation depth of over 0.03 dB μm^−1, induced by a moderate gating voltage of about 10 V. Topologically-protected darkness (zero reflection) was produced by particular engineering of a plasmonic metamaterial. This allowed generation of a singularity in the ellipsometric phase (a particular parameter of light), allowing for measurements of mass sensitivity of ∼10 fg mm^−2, with the possibility of improving this to ∼100 ag mm^−2. Graphene was employed in a novel metrology tool to measure the sensitivity of this device. With respect to fundamental losses in plasmonics, one could find either a new plasmonic material or look to improve an existing one. Work was undertook with respect to this latter option by attempting to preserve the otherwise excellent plasmonic properties of copper and silver through a protective barrier of graphene. This was achieved and illustrated through ellipsometric measurements taken over various timescales. Fabrication of a dielectric loaded waveguide on graphene-protected copper was then carried out, with operation of the waveguide proving successful, possibly opening the field of active graphene-protected metal plasmonics.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:634899 |
| Date | January 2014 |
| Creators | Ansell, Daniel |
| Publisher | University of Manchester |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | https://www.research.manchester.ac.uk/portal/en/theses/graphene-for-enhanced-metal-plasmonics(7bb0ffb1-f46f-498e-bb88-9626021f6f58).html |
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