Surface treatments by applying laser processing have gained a significant attention due to the achievable surface properties along with the selectivity that cannot be realized with other methods. The focus of this research is on investigating and developing laser-based treatment methods, i.e. laser-induced surface oxidation, laser-induced oxygen reduction, and laser-induced periodic surface structures (LIPSS), to address the requirements of specific applications in optics, aesthetics, and anti-counterfeiting, e.g. colour marking and the fabrication of optical devices and diffraction holograms. A single spot oxidation method is proposed to control the size of the oxidation area and its thickness on titanium substrates. A pixel resolution down to the beam spot size with high special control is achieved. To produce diffraction optical devices on glass substrates a direct writing another method is proposed. Especially, the method is implemented and validated for fabricating two-level phase-type FZPs with a nanosecond laser by converting a titanium film on glass substrates into titanium dioxide patterns with a thickness controlled at nano scale. The flexibility and applicability of laser-induced oxidation is extended with a method for erasing colour marks selectively by employing a laser-induced oxygen reduction. Finally, a method for producing LIPSS patterns with varying orientations is developed and then validated for fabricating diffraction gratings on metallic surface.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:768332 |
| Date | January 2018 |
| Creators | Jwad, Tahseen |
| Publisher | University of Birmingham |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://etheses.bham.ac.uk//id/eprint/8867/ |
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