Title page, abstract and table of contents only. The complete thesis in print form is available from the University of Adelaide Library. / With the increasing use of lasers it is necessary to develop materials that can provide protection to eyes and other sensitive devices. This thesis reports on an investigation into optical limiting of Transition Metal Acetylides (TMAs) that transmit ambient light levels of light but block high energy (laser) light across the visible part of the spectrum. A standard optical limiting testbed is used to measure opt~callimiting at 470, 532 and 630 om for a wide range of Pt:ethynyl related TMAs. I report the effect on optical limiting of altering the central bridge, heavy metal, terminal group, solubilising group and oligomerisation. Most of these materials showed poor optical limiting, especially in the red. Two dimers of Pt:ethynyl, however, have clamping levels at 532 om better than that for Pt:ethynyl. I therefore describe a detailed spectroscopic investigation of two series of oligomers and discuss their structure/property relationships. This investigation also includes a precursor ofPtethynyl, PEPE, which shows remarkable limiting. I also report modelling of optical limiting using a 5-level model constructed using the spectroscopic data. I show that the 5-level model can be validated and accurately predicts the limiting for PEPE against both ps and ns pulses. It can also be used to predict ps limiting for Pt:ethynyl and its oligomers. For ns pulses, however, it predicts much less limiting than that observed. I therefore propose a new mechanism that is important for ns limiting by TMAs. Finally I discuss the broadband limiting of these materials and from analysis of the measurements· I describe structures of materials that may show promising broadband optical limiting. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1320307 / Thesis (Ph.D.) -- University of Adelaide, School of Chemistry and Physics, 2008
| Identifer | oai:union.ndltd.org:ADTP/273585 |
| Date | January 2008 |
| Creators | Van Galen, Yvonne Jansen |
| Source Sets | Australiasian Digital Theses Program |
| Detected Language | English |
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