In today's technology an increasing use is made of materials consisting of thin layers with thicknesses in the range of a few nanometers. Applications of these types of materials can be found in integrated circuits, magnetic heads and tapes, solid-state lasers, X-ray mirrors and coated window glass, etc. They are used for their mechanical, magnetic, optical and/or electrical properties. These properties are related to the structural parameters of these materials, such as the elemental composition, thickness, roughness and number of layers in the material. The first part of this thesis explores both the thickness of layers and the number of layers in x-ray multilayer mirrors by using the Luus-Jaakola optimization procedure in order to achieve a desired reflectivity. The reflectivity of multilayer coatings shows a strong dependence on the thickness of each layer and the number of layers. In the first chapter we present and modify the Luus-Jaakola algorithm to design optical th in-film systems by optimizing the thickness of the layers as well as the number of layers. We show that the optimization model can improve the results using fewer layers of material with the Luus-Jaakola method for the design of x-ray multilayer mirrors in both the angular and spectral domains. Numerical results indicate that the proposed approach performs very competitively with other approaches. It has become possible to design optical coatings with fewer layers. This opens a new opportunity for the design of high quality optical coatings. We then apply this technique to help in the design of multilayer mirrors for a target application, such as an astronomical grazing-incidence hard X-ray telescope. These designs are compared with other author's results. Further, we present a computational study of a modification of the Luus-Jaakola method that could be used in multilayer mirrors with more than two components. Then we apply this method to determine the optical constants, thickness and root mean square roughens of the layers. Finally, in the last part of the thesis we present optimization results of phase-only sampled fiber Bragg gratings by using the modified Luus-Jaakola method. We show that it is able to produce a high number of channels with less refractive-index modulation, high reflectivity, as well as requiring fewer segments.
| Identifer | oai:union.ndltd.org:uottawa.ca/oai:ruor.uottawa.ca:10393/29791 |
| Date | January 2009 |
| Creators | Al-Marzoug, Saeed M |
| Publisher | University of Ottawa (Canada) |
| Source Sets | Université d’Ottawa |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | 87 p. |
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