Thesis (M.S. in Physics)--Naval Postgraduate School, December 2009. / Thesis Advisor(s): Walters, Donald. Second Reader: Borden, Brett. "December 2009." Description based on title screen as viewed on January 27, 2010. Author(s) subject terms: Ocean waves, Laser Scattering, Absorption, Refraction. Includes bibliographical references (p. 55). Also available in print.

Thesis (Ph. D.)--University of Texas at Austin, 2003. / Supervisor: David L. Bourell. Vita. Includes bibliographical references. Available also from UMI Company.

Thesis (Ph. D.)--University of Texas at Austin, 2002. / Vita. Includes bibliographical references. Available also from UMI Company.

Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: laser; laser beams; measurement of lasers; crystals; Nd:YAG. Includes bibliographical references (p. 97-98).

The resonant interaction of light with metal nanoparticles can result in extraordinary optical effects in both the near and far fields. Plasmonics, the study of this interaction, has the potential to enhance performance in a wide range of applications, including sensing, photovoltaics, photocatalysis, biomedical imaging, diagnostics, and treatment. However, the mechanisms of plasmonic enhancement often remain poorly understood, limiting the design and effectiveness of plasmonics for advanced applications. This dissertation focuses on evaluating the mechanisms of plasmonic enhancement and distinguishing between near and far field effects using simulations and experimental results. Thorough characterization of metal nanoparticle colloids shows that electromagnetic simulations can be used to accurately predict the optical response of nanoparticles only if the true shapes and size distributions are taken into account. By coupling these optical interaction calculations with heat transfer models, experimental limits for the maximum optical power before nanoparticle melting can be found. These limits are important for plasmonic multiphoton luminescence imaging applications. Subsequently, we demonstrate ultrafast laser plasmonic nanoablation of silicon substrates using gold nanorods to identify the near-field enhancement and mechanism of plasmon-assisted ablation. The experimentally observed shape of the ablation region and reduction of the ablation threshold are compared with simulations to show the importance of the enhanced electromagnetic fields in near-field nanoablation with plasmonic nanoparticles. The targeted use of plasmonic nanoparticles requires narrow size distribution colloids, because wide size distributions result in a blurring and weakening of the optical response. A new synthesis method is presented for the seeded-growth of nearly monodisperse metal nanoparticles ranging from 10 to 100 nm in diameter, both with and without dielectric shells of controlled thickness. This method is used to acquire fine control over the position and width of the plasmonic peak response. We also demonstrate self-assembled sub-monolayers of these particles with controllable concentrations, which is ideal for looking at plasmonic effects in surface and layered geometries. Finally, we present results for the spatial distribution of absorption around plasmonic nanoparticles. We introduce field-based definitions for distinguishing near-field and far-field regions and develop a new set of equations to determine the point-by-point enhanced absorption in a medium around a plasmonic nanoparticle. This set of equations is used to study plasmon-enhanced optical absorption for thin-film photovoltaic cells. Plasmonic nanoparticle systems are identified using simulations and proof-of-concept experiments are used to demonstrate the potential of this approach. / text

Background Glaucoma is a major cause of blindness worldwide. The affected population was projected to increase from 60.5 million in 2010 to 79.6 million in 2020. Among the various types of glaucoma, primary open angle glaucoma will account for more than 70% of this population. Treatment by lowering the intraocular pressure is the only proven method to reduce progression. This can be achieved via medication, surgery and laser. Selective laser trabeculoplasty is a relatively new type of laser that is reported to be equally efficacious to a first line medication and other established laser trabeculoplasty, namely argon laser trabeculoplasty. The evidence available, however, is limited to single trials, which may not reach adequate power to detect the difference. A systematic review and meta-analysis would add evidence to consider selective laser trabeculoplasty as an alternative treatment option in open angle glaucoma through assessing its efficacy and effectiveness in lowering the intraocular pressure and through testing for its non-inferiority when compared with other conventional treatment modalities. Method Literature search of Pubmed, EMBASE, CENTRAL, dissertation and thesis databases and hand search of relevant journals was performed for the use of selective laser trabeculoplasty in the treatment of open angle glaucoma. English and Chinese articles were included. Meta-analysis of randomized controlled trials comparing treatment efficacy of selective laser trabeculoplasty and other treatment modalities were performed where appropriate. Results 80 articles were identified to be relevant and provided sufficient data for interpretation for efficacy or safety assessment. It was estimated that selective laser trabeculoplasty resulted in a weighted pooled mean intraocular pressure reduction of 21.9 to 23.8% at different follow-up durations. However, sensitivity analysis including only prospective studies with baseline IOP less than 21mmHg did not show significant IOP lowering effect. Review on side effects of selective laser trabeculoplasty showed a good safety profile in general. Rare occurrences of more severe or long-term complications included persistent intraocular pressure spike requiring surgery, persistent macular edema and corneal haze. Meta-analysis of randomized controlled trials showed that selective laser trabeculoplasty is non-inferior to argon laser trabeculoplasty and medication in intraocular pressure reduction and also in achieving treatment success. Number of medication reduction is similar between selective laser trabeculoplasty and argon laser trabeculoplasty. Conclusion This report demonstrated comparable efficacy of selective laser trabeculoplasty with argon laser trabeculoplasty and medication therapy in the treatment of open angle glaucoma. / published_or_final_version / Public Health / Master / Master of Public Health

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