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Fabrication and characterisation of photorefractive thin films and waveguides

Fabrication and characterisation of photorefractive thin films and waveguides
Fabrication and characterisation of photorefractive thin films and waveguides
This thesis is concerned with the fabrication and characterisation of photorefractive planar waveguides by the techniques of pulsed laser deposition and ion-beam implantation. The formation of photorefractive waveguides is highly desirable for the miniaturisation of optical systems and provides compatibility with other integrated optical devices in current use such as waveguide lasers and optical fibre technology. The optical confinement inherent to waveguides also holds the key to a major speed up in the effective response time of the photorefractive effect. Up to three orders of magnitude decrease is forecast due to the intensity dependence of the photorefractive response time.

This thesis reports the epitaxial growth of thin film optical waveguides of the photorefractive materials Bi12GeO20 and Bi12SiO20 onto heated zirconia substrates by pulsed laser deposition. The epitaxial nature and stoichiometry of the films are verified using x-ray diffraction analysis. Waveguide modes were observed with effective refractive indices in close agreement with theoretical predictions implying that the refractive index of the deposited film is similar to that of the bulk crystal. Pulsed laser deposition has also been used to fabricate waveguides from the chalcogenide glass lanthanum/gallium sulphide. The waveguides demonstrate many characteristic chalcogenide properties such as photo-bleaching, photo-diffusion and a photo-induced change in the refractive index.

Ion-beam implantation has been successfully used to form planar waveguides in the photorefractive materials Bi12SiO20, SrxBa1-xNb206 and BaTiO3. The annealing of SBN waveguides and the effect on waveguide propagation loss is discussed. Photorefractive effects have been observed and characterised in BaTiO3. The expected decrease in the effective photorefractive response time (for a given input power) has been observed, owing to a combination of optical confinement within the waveguide and possible modification of charge-transport properties induced through implantation. Photorefractive two-beam coupling experiments exhibited a decrease in the response time of >102, and an unexpected reversal of the gain direction in the waveguide compared with that of the bulk crystal.
Youden, Katharine Emily
aabd2697-cf24-4a6b-b0d4-c6a1e69f507b
Youden, Katharine Emily
aabd2697-cf24-4a6b-b0d4-c6a1e69f507b
Eason, Robert
e38684c3-d18c-41b9-a4aa-def67283b020

Youden, Katharine Emily (1992) Fabrication and characterisation of photorefractive thin films and waveguides. University of Southampton, Faculty of Science, Doctoral Thesis, 175pp.

Record type: Thesis (Doctoral)

Abstract

This thesis is concerned with the fabrication and characterisation of photorefractive planar waveguides by the techniques of pulsed laser deposition and ion-beam implantation. The formation of photorefractive waveguides is highly desirable for the miniaturisation of optical systems and provides compatibility with other integrated optical devices in current use such as waveguide lasers and optical fibre technology. The optical confinement inherent to waveguides also holds the key to a major speed up in the effective response time of the photorefractive effect. Up to three orders of magnitude decrease is forecast due to the intensity dependence of the photorefractive response time.

This thesis reports the epitaxial growth of thin film optical waveguides of the photorefractive materials Bi12GeO20 and Bi12SiO20 onto heated zirconia substrates by pulsed laser deposition. The epitaxial nature and stoichiometry of the films are verified using x-ray diffraction analysis. Waveguide modes were observed with effective refractive indices in close agreement with theoretical predictions implying that the refractive index of the deposited film is similar to that of the bulk crystal. Pulsed laser deposition has also been used to fabricate waveguides from the chalcogenide glass lanthanum/gallium sulphide. The waveguides demonstrate many characteristic chalcogenide properties such as photo-bleaching, photo-diffusion and a photo-induced change in the refractive index.

Ion-beam implantation has been successfully used to form planar waveguides in the photorefractive materials Bi12SiO20, SrxBa1-xNb206 and BaTiO3. The annealing of SBN waveguides and the effect on waveguide propagation loss is discussed. Photorefractive effects have been observed and characterised in BaTiO3. The expected decrease in the effective photorefractive response time (for a given input power) has been observed, owing to a combination of optical confinement within the waveguide and possible modification of charge-transport properties induced through implantation. Photorefractive two-beam coupling experiments exhibited a decrease in the response time of >102, and an unexpected reversal of the gain direction in the waveguide compared with that of the bulk crystal.

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More information

Published date: December 1992
Organisations: University of Southampton, Physics & Astronomy

Identifiers

Local EPrints ID: 399136
URI: https://eprints.soton.ac.uk/id/eprint/399136
PURE UUID: b20d191e-b673-4b06-95ad-c72269c5f5b6
ORCID for Robert Eason: ORCID iD orcid.org/0000-0001-9704-2204

Catalogue record

Date deposited: 16 Sep 2016 15:26
Last modified: 24 Jul 2018 00:38

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