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Title: Direct UV writing of structures in lithium niobate and lithium tantalate
Author: Wellington, Iain
ISNI:       0000 0001 3565 7019
Awarding Body: University of Southampton
Current Institution: University of Southampton
Date of Award: 2007
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This thesis presents results from fabrication of UV direct write structures in lithium niobate and lithium tantalate. Unassisted direct writing of surface channel waveguides using lambda = 244 nm cw light resulted in polarisation specific waveguides fabricated on z- cut crystals. Waveguides were characterised using mode profiles, propagation losses, numerical aperture and refractive index measurements. In z-cut congruent lithium niobate, waveguides were written on the +z and -z faces producing structures that guided TM polarisation only with +z face waveguides exhibiting the lowest propagation loss of ~ 2 dB/cm, a maximum refractive index difference of ~ 8 x 10Surface ferroelectric domain reversal via illumination of single pulsed lambda = 266 nm light through a phasemask on +z face congruent lithium niobate produced ordered alignment of domain lines along the crystallographic y-axes with minimum domain separation width of ~ 2 μm. Results from high temperature exposures and multipulse regimes are presented and a domain formation mechanism is proposed via an Nb anti-site model.
Supervisor: Eason, Robert Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: TK Electrical engineering. Electronics Nuclear engineering ; QC Physics