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You searched for subject:(Transverse Anderson localization). Showing records 1 – 2 of 2 total matches.

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Clemson University

1. Tuggle, Matthew Artus. Material Properties of Anderson Localizing Optical Fiber.

Degree: PhD, School of Materials Science and Engineering, 2020, Clemson University

Over half a century ago, the paper entitled “Absence of Diffusion in Certain Random Lattices” was published by P. Anderson and described a metal-to-insulator transition phenomenon where electron diffusion does not occur in disordered semiconductors. This phenomenon is now commonly referred to as “Anderson localization” (AL). Since the AL detailed in Anderson’s paper arose from the wave nature of electrons, similar behavior should be observed in other wave systems, more specifically in optics. Given the utility of optical fibers, extensive theoretical treatment has been conducted on transverse Anderson localization (TAL, disorder in x- and y-directions, with the z-direction remaining invariant) in such systems. Only recently has it been experimentally observed, paving the way for studies into the influence of fiber material on linear and nonlinear TAL. This Dissertation represents the first materials study of doped silicate transverse Anderson localizing optical fibers (TALOFs) and their corresponding passive and active optical properties. More specifically, Chapter I reviews microstructured and multicore optical fiber, and methods of their fabrication, in order to develop an understanding of the impact of the core microstructure on waveguide properties. Then, an overview of TALOFs is developed to provide insights into the different materials and fabrication methods used to develop the few TALOFs reported to date. The former fiber systems are well studied; therefore, this research Dissertation will be focused on the novel effects and material influences on the latter (Anderson) systems. Chapter II begins the development of these novel fibers through in situ phase separation in optical fibers drawn using the molten core method (MCM). Limitations in the resulting fibers were studied, and adaptations to the fabrication method were made to elongate the already formed microphases through development and subsequent use of a two-tier MCM. Chapter III introduces an alternative fiber fabrication technique, namely the stack-and-draw method, specifically adapted to utilize MCM-derived precursor fibers in the stack. The resulting fibers are characterized to understand the effects of processing on the core microstructure, and ultimately to understand how the core microstructure leads to TAL. Chapters IV and V investigate the material properties and potential applications of the TALOFs that resulted from the fabrication technique developed in Chapter III. Specifically, Chapter IV investigates both Yb3+ and Er3+ doped TALOFs for solid-state lasing and amplification respectively. The resulting experimental observations and present limitations of these fibers for active applications are discussed. In Chapter V, the first nonlinear optical TALOFs are explored. Even though the higher refractive index phases possessed an estimated nonlinear refractive index (n2) similar to silica, small modal effective areas were demonstrated due to the strong localization in… Advisors/Committee Members: John Ballato, Arash Mafi, Stephen Foulger, Konstantin Kornev.

Subjects/Keywords: Fiber fabrication; Glass; Microstructure; Optical fibers; Optical nonlinearities; Transverse Anderson localization

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

APA (6th Edition):

Tuggle, M. A. (2020). Material Properties of Anderson Localizing Optical Fiber. (Doctoral Dissertation). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_dissertations/2584

Chicago Manual of Style (16th Edition):

Tuggle, Matthew Artus. “Material Properties of Anderson Localizing Optical Fiber.” 2020. Doctoral Dissertation, Clemson University. Accessed September 30, 2020. https://tigerprints.clemson.edu/all_dissertations/2584.

MLA Handbook (7th Edition):

Tuggle, Matthew Artus. “Material Properties of Anderson Localizing Optical Fiber.” 2020. Web. 30 Sep 2020.

Vancouver:

Tuggle MA. Material Properties of Anderson Localizing Optical Fiber. [Internet] [Doctoral dissertation]. Clemson University; 2020. [cited 2020 Sep 30]. Available from: https://tigerprints.clemson.edu/all_dissertations/2584.

Council of Science Editors:

Tuggle MA. Material Properties of Anderson Localizing Optical Fiber. [Doctoral Dissertation]. Clemson University; 2020. Available from: https://tigerprints.clemson.edu/all_dissertations/2584

2. Kondakci, Hasan. Photon Statistics in Disordered Lattices.

Degree: 2015, University of Central Florida

Propagation of coherent waves through disordered media, whether optical, acoustic, or radio waves, results in a spatially redistributed random intensity pattern known as speckle  – a statistical phenomenon. The subject of this dissertation is the statistics of monochromatic coherent light traversing disordered photonic lattices and its dependence on the disorder class, the level of disorder and the excitation configuration at the input. Throughout the dissertation, two disorder classes are considered, namely, diagonal and off-diagonal disorders. The latter exhibits disorder-immune chiral symmetry  – the appearance of the eigenmodes in skew-symmetric pairs and the corresponding eigenvalues in opposite signs. When a disordered photonic lattice, an array of evanescently coupled waveguides, is illuminated with an extended coherent optical field, discrete speckle develops. Numerical simulations and analytical modeling reveal that discrete speckle shows a set of surprising features, that are qualitatively indistinguishable in both disorder classes. First, the fingerprint of transverse Anderson localization  – associated with disordered lattices, is exhibited in the narrowing of the spatial coherence function. Second, the transverse coherence length (or speckle grain size) freezes upon propagation. Third, the axial coherence depth is independent of the axial position, thereby resulting in a coherence voxel of fixed volume independently of position. When a single lattice site is coherently excited, I discovered that a thermalization gap emerges for light propagating in disordered lattices endowed with disorder-immune chiral symmetry. In these systems, the span of sub-thermal photon statistics is inaccessible to the input coherent light, which  – once the steady state is reached  – always emerges with super-thermal statistics no matter how small the disorder level. An independent constraint of the input field for the chiral symmetry to be activated and the gap to be observed is formulated. This unique feature enables a new form of photon-statistics interferometry: by exciting two lattice sites with a variable relative phase, as in a traditional two-path interferometer, the excitation-symmetry of the chiral mode pairs is judiciously broken and interferometric control over the photon statistics is exercised, spanning sub-thermal and super-thermal regimes. By considering an ensemble of disorder realizations, this phenomenon is demonstrated experimentally: a deterministic tuning of the intensity fluctuations while the mean intensity remains constant. Finally, I examined the statistics of the emerging light in two different lattice topologies: linear and ring lattices. I showed that the topology dictates the light statistics in the off-diagonal case: for even-sited ring and linear lattices, the electromagnetic field evolves into a single quadrature component, so that the field takes discrete phase values and is non-circular in the complex plane. As a consequence, the statistics become super-thermal. For odd-sited ring lattices,… Advisors/Committee Members: Saleh, Bahaa.

Subjects/Keywords: Photonic lattices; waveguide arrays; coherence photon statistics; disorder; disordered lattices; coupled waveguides; photon number distribution; diagonal disorder; off diagonal disorder; photonic thermalization gap; discrete anderson speckle; anderson localization; transverse localization; topology; Electromagnetics and Photonics; Optics; <; p>; Dissertations, Academic  – Optics and Photonics; Optics and Photonics  – Dissertations, Academic<; /p>

…lattices. I show that there are alternative signatures of transverse Anderson localization in the… …speckle in one- and two-dimensional lattices known to exhibit transverse Anderson localization… …Anderson Speckle – Transverse Coherence 2.3.1 Anderson Localization To set the stage for… …transverse coherence width and the localization length. In the discrete Anderson speckle regime… …7 2.3 Discrete Anderson Speckle – Transverse Coherence… 

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

APA (6th Edition):

Kondakci, H. (2015). Photon Statistics in Disordered Lattices. (Doctoral Dissertation). University of Central Florida. Retrieved from https://stars.library.ucf.edu/etd/1461

Chicago Manual of Style (16th Edition):

Kondakci, Hasan. “Photon Statistics in Disordered Lattices.” 2015. Doctoral Dissertation, University of Central Florida. Accessed September 30, 2020. https://stars.library.ucf.edu/etd/1461.

MLA Handbook (7th Edition):

Kondakci, Hasan. “Photon Statistics in Disordered Lattices.” 2015. Web. 30 Sep 2020.

Vancouver:

Kondakci H. Photon Statistics in Disordered Lattices. [Internet] [Doctoral dissertation]. University of Central Florida; 2015. [cited 2020 Sep 30]. Available from: https://stars.library.ucf.edu/etd/1461.

Council of Science Editors:

Kondakci H. Photon Statistics in Disordered Lattices. [Doctoral Dissertation]. University of Central Florida; 2015. Available from: https://stars.library.ucf.edu/etd/1461

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