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Electromagnetic modelling and rational design of GLAD thin films for optical applications
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- Author / Creator
- Leontyev, Viktor A
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This thesis presents a theoretical study of columnar films, fabricated by glancing angle deposition (GLAD), as photonic bandgap structures and metamaterials with predictable dielectric and magnetic response.
Glancing angle deposition (GLAD) employs extremely oblique vapour incidence and computerized substrate motion to produce nanocolumns with a variety of shapes.
Columns grow in random or periodic arrays and may be periodic in one, two, or three dimensions.
The films' optical properties were studied using finite-difference time-domain and finite-difference frequency-domain methods, as well as effective medium theories, with support from experimental research.
A large part of the thesis is devoted to column arrays with subwavelength intercolumnar distance and periodically modulated column shape.
Among them, s-shaped columns were designed as polarizers for linearly polarized light.
Simulations have shown a competitive effect from two structural anisotropy sources, causing a band gap suppression for one of two linear polarizations, and high polarizing ability.
Simulations were compared to the measurements with a very good agreement in spectral response.
Subwavelength column arrays were further explored as anisotropic interference mirrors with omnidirectional reflection bands.
Index graded vertical post films were designed, having up to four times wider reflection bands than in the isotropic analogs.
Band gap properties of 3D periodic GLAD columns were studied on the example of square-spiral photonic crystals.
A significant influence of column cross-section was shown, that currently prevents fabrication of square spirals with a 3D band gap in the visible range.
Inverted square-spiral films have better performance, which is further improved by material redistribution along the spiral.
Lastly, this work studies the effective dielectric response of porous columnar films with metal particles.
Characteristic matrix formalism was combined with finite-difference modelling to explicitly calculate their permittivity and permeability, and to study the band gap formation in periodic layers of porous metal.
Anisotropic magnetic response was observed in silver columns away from the plasma resonance.
Combined with a large permittivity in the infrared, this has potential for future refractive index engineering.
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- Graduation date
- Spring 2013
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- Type of Item
- Thesis
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- Degree
- Doctor of Philosophy
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- License
- This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.