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You searched for +publisher:"Clemson University" +contributor:("Dr. Stephen Foulger"). Showing records 1 – 3 of 3 total matches.

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Clemson University

1. Vargas, Amber L. Nanoparticle Doped Optical Fibers for High Energy Lasers.

Degree: MS, School of Materials Science and Engineering, 2019, Clemson University

Fabrication of rare earth (RE) doped optical fibers for use in fiber-based lasers and amplifiers is conventionally performed using a solution doping technique where RE salts (i.e., ErCl3) are dissolved in a solvent, introduced into the porous silica soot, dried and consolidated to form the active fiber core. This process does not allow for tailoring of the chemical environment about the RE. Alternatively, nanoparticle (NP) doping is more recent approach to incorporating rare earths into an optical fiber and have been shown to permit modification of the chemical environment around the RE in ways the enhance spectroscopic performance. This is due to the NP isolating the dopant from the host SiO2 glass by creating a protective “shell” surrounding the RE. The NP host should to have a lower phonon energy than the SiO2 (1100 cm^-1) matrix since the radiative and non-radiative processes influence lasing efficiencies. In this Thesis, lanthanum trifluoride (LaF3) was selected as the NP of choice since it possesses a low phonon energy (~350 cm^-1) and while the fluoride converts to an oxide during the fiber processing, a lower phonon energy environment still remains about the RE. More specifically, NP doping was performed for fabricating and studying erbium doped fibers, where Er3+-doped lanthanum fluoride (Er:LaF3) NPs were synthesized and their properties investigated to determine advantages for NP doping to conventional soluble salt doping. In addition, for this Thesis, different rare earth NP suspensions were produced and studied along with the effects of different host materials in those suspensions. Slope efficiencies in excess of 70% were realized for Er3+ nanoparticle doping in a multimode fiber-based master oscillator power amplifier (MOPA). This Thesis will discuss the systematic study of NP and fiber properties. More specifically, NP doped suspensions and fibers were characterized and discussed by their physical, chemical, and spectroscopic properties to develop an understanding as to how to tailor and HEL relevant performance parameters. Advisors/Committee Members: Dr. John Ballato, Committee Chair, Dr. Philip Brown, Dr. Stephen Foulger.

Subjects/Keywords: Materials Science and Engineering

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APA (6th Edition):

Vargas, A. L. (2019). Nanoparticle Doped Optical Fibers for High Energy Lasers. (Masters Thesis). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_theses/3032

Chicago Manual of Style (16th Edition):

Vargas, Amber L. “Nanoparticle Doped Optical Fibers for High Energy Lasers.” 2019. Masters Thesis, Clemson University. Accessed September 29, 2020. https://tigerprints.clemson.edu/all_theses/3032.

MLA Handbook (7th Edition):

Vargas, Amber L. “Nanoparticle Doped Optical Fibers for High Energy Lasers.” 2019. Web. 29 Sep 2020.

Vancouver:

Vargas AL. Nanoparticle Doped Optical Fibers for High Energy Lasers. [Internet] [Masters thesis]. Clemson University; 2019. [cited 2020 Sep 29]. Available from: https://tigerprints.clemson.edu/all_theses/3032.

Council of Science Editors:

Vargas AL. Nanoparticle Doped Optical Fibers for High Energy Lasers. [Masters Thesis]. Clemson University; 2019. Available from: https://tigerprints.clemson.edu/all_theses/3032


Clemson University

2. Buelt, Ashley A. Optically Active and Stimuli-Responsive Macromolecules: Photophysics, Morphology and Sensor Applications.

Degree: PhD, Chemistry, 2014, Clemson University

Conjugated polymers are of particular interest for many device applications, especially those involving optoelectronics. Not only is there a potential for π-conjugated organic materials to replace inorganic materials in applications such as solar cells and light emitting diodes, but there is also the possibility for these materials to serve as key components of cheaper, more environmentally-friendly, lighter and more flexible materials. For over thirty years, researchers have been striving to understand the morphology, electrochemical and photophysical properties of this new class of organic materials. The work presented herein advances the field through synthetic design and morphological studies. In addition, several novel materials for metal ion and nitroorganic detection have been discovered. The work delineated in Chapter 2 reveals the utility of the m-terphenyl unit to provide steric control of intra- and interchain interactions. A charge transfer band and a FRET effect were observed from materials prepared via simple post-polymerization modification. In Chapter 3, the detection of nitro-organics using several new polymers is discussed, with an extensive comparison to the literature. Steric, electronic, media polarity, and aggregation effects proved influential in the polymer-analyte interaction. In Chapter 4 work is outlined wherein the morphology of polymers in solution and the solid state is further examined. The study revealed a correlation between aggregation in solution and eventual nanomorphology of films derived from the solutions. Chapter 5 expands upon the work in Chapter 2 with an exploration of six new polymers that were generated via post-polymerization of two parent polymers via Sonogashira coupling. The new polymers were examined for use in metal ion and nitroorganic fluorescence response. The metal ion studies revealed the polymers to be tunable based on the donor or acceptor character of the spacer unit. From the detection of 2,4-dinitrotoluene, one polymer was found to have a comparable ultimate quenching efficiency to those discussed in Chapter 3. Advisors/Committee Members: Dr. Rhett C. Smith, Committee Chair, Dr. Karl Dieter, Dr. Jason McNeill, Dr. Stephen Foulger.

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Buelt, A. A. (2014). Optically Active and Stimuli-Responsive Macromolecules: Photophysics, Morphology and Sensor Applications. (Doctoral Dissertation). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_dissertations/1794

Chicago Manual of Style (16th Edition):

Buelt, Ashley A. “Optically Active and Stimuli-Responsive Macromolecules: Photophysics, Morphology and Sensor Applications.” 2014. Doctoral Dissertation, Clemson University. Accessed September 29, 2020. https://tigerprints.clemson.edu/all_dissertations/1794.

MLA Handbook (7th Edition):

Buelt, Ashley A. “Optically Active and Stimuli-Responsive Macromolecules: Photophysics, Morphology and Sensor Applications.” 2014. Web. 29 Sep 2020.

Vancouver:

Buelt AA. Optically Active and Stimuli-Responsive Macromolecules: Photophysics, Morphology and Sensor Applications. [Internet] [Doctoral dissertation]. Clemson University; 2014. [cited 2020 Sep 29]. Available from: https://tigerprints.clemson.edu/all_dissertations/1794.

Council of Science Editors:

Buelt AA. Optically Active and Stimuli-Responsive Macromolecules: Photophysics, Morphology and Sensor Applications. [Doctoral Dissertation]. Clemson University; 2014. Available from: https://tigerprints.clemson.edu/all_dissertations/1794

3. Cavillon, Maxime. Molten Core Fabrication of Intrinsically Low Nonlinearity Glass Optical Fibers.

Degree: PhD, School of Materials Science and Engineering, 2018, Clemson University

Optical nonlinearities limit scaling to higher output powers in modern fiber-based laser systems. Paramount amongst these parasitic phenomena are stimulated Brillouin scattering (SBS), stimulated Raman scattering (SRS), and nonlinear refractive index (n2)-related wave-mixing phenomena (e.g., self-phase modulation, SPM, four-wave mixing, FWM). In order to mitigate these effects, the fiber community has largely focused on the development of micro-structured large mode area (LMA) fibers whereby the fiber geometry is engineered to spread the optical power over a larger effective area. In addition to increasing the resultant complexity and cost of these fibers, such LMA designs introduce new parasitic phenomena, such as transverse mode instability (TMI), which presently serves as the dominant limitation in power-scaling. This dissertation explores a different approach for mitigating these nonlinearities in optical fiber lasers; namely attacking the aforementioned effects at their fundamental origin, i.e., the material through which the light propagates. Indeed, the Brillouin gain coefficient (BGC), the Raman gain coefficient (RGC), the thermo-optic coefficient (TOC) and the nonlinear refractive index (n2) are all intrinsic material properties that respectively drive SBS, SRS, TMI and wave-mixing phenomena. Though less well studied within the fiber laser community, such a materials approach offers a powerful yet simpler way to address nonlinearities. Chapter I investigates the thermodynamic origins of light scattering and provides insight into the prime material properties that drive optical nonlinearities. Chapters II and III offer an overview of how these (and other) properties can be measured and modeled in multicomponent glass systems, considering both bulk or fiber geometries. In Chapter IV, a materials road map for binary and ternary glass material systems is provided to identify which compositions should be of specific focus for the development of intrinsically low optical nonlinearity optical fibers. These four Chapters have been adapted from a series of published journal articles1 entitled “A unified materials approach to mitigating optical nonlinearities in optical fiber” [1]–[4]. In Chapter V, the fabrication of oxyfluoride-core silica-cladding optical fibers using the molten core method is described and their core glass compositions and structures investigated. The thermodynamics and kinetics of fluoride-oxide reactions are also studied, and insights on the dominant mechanisms that drive the fluoride-oxide reactions during fiber processing are discussed. In Chapter VI, optical properties that drive optical nonlinearities are studied, and their relationships with glass compositions investigated. Oxyfluoride fibers exhibiting concomitant reductions of 6-9 dB in BGC, 0.5-1.5 dB in RGC, and 1.2-3.2 dB in TOC, relative to conventional silica fibers, as well as reduced linear and nonlinear refractive indices, are reported. Spectroscopic properties of active Yb-doped fibers are also considered,… Advisors/Committee Members: Dr. John Ballato, Committee Chair, Dr. Peter Dragic, Dr. Liang Dong, Dr. Stephen Foulger, Dr. Philip Brown.

Subjects/Keywords: Glass materials; Optical fibers; Optical nonlinearities; Oxyfluorides; Silicates

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Cavillon, M. (2018). Molten Core Fabrication of Intrinsically Low Nonlinearity Glass Optical Fibers. (Doctoral Dissertation). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_dissertations/2162

Chicago Manual of Style (16th Edition):

Cavillon, Maxime. “Molten Core Fabrication of Intrinsically Low Nonlinearity Glass Optical Fibers.” 2018. Doctoral Dissertation, Clemson University. Accessed September 29, 2020. https://tigerprints.clemson.edu/all_dissertations/2162.

MLA Handbook (7th Edition):

Cavillon, Maxime. “Molten Core Fabrication of Intrinsically Low Nonlinearity Glass Optical Fibers.” 2018. Web. 29 Sep 2020.

Vancouver:

Cavillon M. Molten Core Fabrication of Intrinsically Low Nonlinearity Glass Optical Fibers. [Internet] [Doctoral dissertation]. Clemson University; 2018. [cited 2020 Sep 29]. Available from: https://tigerprints.clemson.edu/all_dissertations/2162.

Council of Science Editors:

Cavillon M. Molten Core Fabrication of Intrinsically Low Nonlinearity Glass Optical Fibers. [Doctoral Dissertation]. Clemson University; 2018. Available from: https://tigerprints.clemson.edu/all_dissertations/2162

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