To see the other types of publications on this topic, follow the link: Photonics Mathematics.
Dissertations / Theses on the topic 'Photonics Mathematics'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 30 dissertations / theses for your research on the topic 'Photonics Mathematics.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Flanagan, Michael Brady. "Optimal shape design for a layered periodic structure." Texas A&M University, 2002. http://hdl.handle.net/1969/382.
Full text
2
Yamashita, Tsuyoshi. "Unraveling photonic bands : characterization of self-collimation in two-dimensional photonic crystals." Diss., Available online, Georgia Institute of Technology, 2005, 2005. http://etd.gatech.edu/theses/available/etd-06072005-104606/.
Full textAbstract:
Thesis (Ph. D.)--School of Materials Science and Engineering, Georgia Institute of Technology, 2006.Summers, Christopher, Committee Chair ; Chang, Gee-Kung, Committee Member ; Carter, Brent, Committee Member ; Wang, Zhong Lin, Committee Member ; Meindl, James, Committee Member ; Li, Mo, Committee Member.
3
Norton, Richard. "Numerical computation of band gaps in photonic crystal fibres." Thesis, University of Bath, 2008. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.501623.
Full textAbstract:
Photonic crystal fibres are capable of special light guiding properties that ordinary optical fibres do not possess, and efforts have been made to numerically model these properties. The plane wave expansion method is one of the numerical methods that has been used. Unfortunately, the function that describes the material in the fibre n(x) is discontinuous, and convergence of the plane wave expansion method is adversely affected by this. For this reason, the plane wave expansion method may not be every applied mathematician’s first choice method but we will show that it is comparable in implementation and convergence to the standard finite element method. In particular,an optimal preconditioner for the system matrix A can easily be obtained and matrixvector products with A can be computed in O(N logN) operations (where N is the size of A) using the Fast Fourier Transform. Although we are always interested in the efficiency of the method, the main contribution of this thesis is the development of convergence analysis for the plane wave expansion method applied to 4 different 2nd-order elliptic eigenvalue problems in R and R2 with discontinuous coefficients. To obtain the convergence analysis three issues must be confronted: regularity of the eigenfunctions; approximation error with respect to plane waves; and stability of the plane wave expansion method. We successfully tackle the regularity and approximation error issues but proving stability relies on showing that the plane wave expansion method is equivalent to a spectral Galerkin method, and not all of our problems allow this. However, stability is observed in all of our numerical computations. It has been proposed in [40], [53], [63] and [64] that replacing the discontinuous coefficients in the problem with smooth coefficients will improve the plane wave expansion method, despite the additional error. Our convergence analysis for the method in[63] and [64] shows that the overall rate of convergence is no faster than before. To define A we need the Fourier coefficients of n(x), and sometimes these must be approximated, thus adding an additional error. We analyse the errors for a method where n(x) is sampled on a uniform grid and the Fourier coefficients are computed with the Fast Fourier Transform. We then devise a strategy for setting the grid-spacing that will recover the convergence rate of the plane wave expansion method with exact Fourier coefficients.
4
Lechleiter, Armin [Verfasser], and A. [Akademischer Betreuer] Kirsch. "Factorization methods for photonics and rough surfaces / Armin Lechleiter ; Betreuer: A. Kirsch." Karlsruhe : KIT Scientific Publishing, 2008. http://d-nb.info/118522498X/34.
Full text
5
Beckett, Duan Hugh. "Eigenvalue algorithms and their application to photonic crystal device modelling." Thesis, University of Southampton, 2003. https://eprints.soton.ac.uk/45909/.
Full textAbstract:
In this thesis three methods are presented which calculate the lowest eigenvalues of a set of extremely sparse generalized eigenvalue problems which arise from modelling photonic crystal (PC) structures with the Finite Element Method in 2D and 3D. These are (1) Subspace Iteration, (2) a spectral solver based on Fourier Analysis or Maximum Entropy and (3) an Implicitly Restarted Lanczos Algorithm. Each eignevalue solver was used in a unique way to increase the efficiency of calculating the lowest few eigenvalues of a set of similar generalized eigenvalue problems. For Subspace Iteration using a low fractional accuracy and only 2 extra vectors accurate results can still be obtained with only ~ 2.2 iterations until convergence. By using Maximum Entropy or Fourier Analysis accurate density of states diagrams could be produced for propagating modes combined given a set of moments calculated from matrix vector products. A parallel implementation of this technique is presented. Modelling 3-dimensional photonic crystals with the Vector Finite Elerment Method leads to a large number of zero eigenvalues which do not represent physical modes. They were ‘filtered’ out by using an Implicitly Restarted Lanczos Method which selects the zero eigenvalue as a shift in the shifted QR scheme as it begins to converge. Taking advantage of the development of a highly efficient solver for the PC problem and the use of a grid-enabled cluster, the final chapters are an initial study in exploiting our modelling capability for optimising PC structures consisting of various configurations of rods. There are three main results: (1) from an initial sample of several thousand PC structures the best ones were optimised using a simple gradient descent technique; (2) a set of canonical structures were optimised, and (3) the effect of fabrication tolerances on the properties of a PC with a triangular lattice were investigated. The optimisation increased the size of the gap-midgap ratio by over 200% in some cases. By allowing for errors in the position and radius of the rods it was shown that with current manufacturing processes potentially homogeneous band gap could be destroyed.
6
Schmalkoke, Philipp [Verfasser], and M. [Akademischer Betreuer] Plum. "On the Spectral Properties of Dispersive Photonic Crystals / Philipp Schmalkoke. Betreuer: M. Plum." Karlsruhe : KIT-Bibliothek, 2013. http://d-nb.info/1034356860/34.
Full text
7
Caccavano, Adam. "Optics and Spectroscopy in Massive Electrodynamic Theory." PDXScholar, 2013. https://pdxscholar.library.pdx.edu/open_access_etds/1485.
Full textAbstract:
The kinematics and dynamics for plane wave optics are derived for a massive electrodynamic field by utilizing Proca's theory. Atomic spectroscopy is also examined, with the focus on the 21 cm radiation due to the hyperfine structure of hydrogen. The modifications to Snell's Law, the Fresnel formulas, and the 21 cm radiation are shown to reduce to the familiar expressions in the limit of zero photon mass.
8
Anic, Branimir [Verfasser], and W. [Akademischer Betreuer] Dörfler. "The Fourier-Galerkin Method for Band Structure Computations of 2D and 3D Photonic Crystals / Branimir Anic. Betreuer: W. Dörfler." Karlsruhe : KIT-Bibliothek, 2013. http://d-nb.info/1048384896/34.
Full text
9
Klindworth, Dirk [Verfasser], Kersten [Akademischer Betreuer] Schmidt, Patrick [Gutachter] Joly, Volker [Gutachter] Mehrmann, and Kersten [Gutachter] Schmidt. "On the numerical computation of photonic crystal waveguide band structures / Dirk Klindworth ; Gutachter: Patrick Joly, Volker Mehrmann, Kersten Schmidt ; Betreuer: Kersten Schmidt." Berlin : Technische Universität Berlin, 2015. http://d-nb.info/1156018501/34.
Full text
10
Căbuz, Alexandru Ioan. "Métamatériaux Electromagnétiques - Des Cristaux Photoniques aux Composites à Indice Négatif." Phd thesis, Université Montpellier II - Sciences et Techniques du Languedoc, 2007. http://tel.archives-ouvertes.fr/tel-00161428.
Full textAbstract:
Composite metamaterials are periodic metal-dielectric structures operating at wavelengths larger than the structure period. If properly designed these structures behave as homogeneous media described by effective permittivity and permeability parameters. These effective parameters can be designed to take values in domains that are not available in naturally occurring media; notably it is possible to design composite metamaterials with simultaneously negative permittivity and permeability, or, in other words, with a negative refractive index. However, in many experimental or numerical studies it is far from obvious that the use of a homogeneous model is justified for a given structure at a given wavelength. This issue is often glossed over in the literature. In this work I take a detailed look at the fundamental assumptions on which effective medium models rely and put forward a method for determining frequency domains where a given structure may or may not be accurately described by homogeneous effective medium parameters. This work opens the door to a more detailed understanding of the transition between homogeneous and inhomogeneous behavior in composite metamaterials, in particular by introducing the novel notions of custom made effective medium model, and of meta-photonic crystal.
11
Claudio, Kleucio. "Elementos finitos com resolução simplificada de sistemas de equações lineares para dispositivos fotônicos." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/260408.
Full textAbstract:
Orientador: Hugo Enrique Hernández-FigueroaTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação
Made available in DSpace on 2018-08-16T06:54:22Z (GMT). No. of bitstreams: 1 Claudio_Kleucio_D.pdf: 3139134 bytes, checksum: 900508bd03693258d7011b6af9debd55 (MD5) Previous issue date: 2010
Resumo: O método de elementos finitos é largamente empregado na modelagem de problemas de eletromagnetismo. A modelagem implícita deste método recai em resolver sistemas de equações lineares esparsas, esta etapa é de alto custo computacional. Este trabalho propõe alternativas com o objetivo de melhorar o desempenho computacional das aplicações provenientes de formulações via elementos finitos, através do aproveitamento de soluções de sistemas de equações lineares por métodos direto e iterativo, para simular dispositivos ópticos com as características físicas alteradas constantemente. Na solução dos sistemas de equações, utilizou-se o método direto com Small Rank Adjustment e o método iterativo gradiente bi-conjugado estabilizado precondicionado com análises de reaproveitamento do precondicionador ILUT. Nos estudos desenvolvidos obteve-se um melhor desempenho computacional quando se utilizou o método iterativo. Estes resultados são de grande importância na área de otimização de dispositivos fotônicos tais como acopladores, filtros, demultiplexadores, etc, pois a otimização destes dispositivos consiste em avaliar várias configurações do espaço de busca, implicando em resolver vários sistemas de equações lineares similares provenientes do método de elementos finitos.
Abstract: The Finite Element Method is one of the most popular numerical tools in electromagnetics. Implicit schemes require the solution of sparse linear equation systems, this step demands a lot of computational time. This work proposes alternatives enhancements to obtain better computational performance of such implicit schemes. This was made through the improvement of direct and iterative methods, for problems which may be interpreted as perturbations of a given original one. This is very important specially in the optimization process of devices, due to the fact that one needs to solve many linear systems with little changes at each step, to explore the search space, so many perturbed linear systems are solved to obtain the optimum device. For direct methods the Small Rank Adjustment technique was used, while for iterative methods, the Preconditioned Gradient Stabilized Biconjugate Method reusing the preconditioner, were adopted. The applications were focused on the design of photonic devices, like couplers, filters, demultiplexers, etc.
Doutorado
Telecomunicações e Telemática
Doutor em Engenharia Elétrica
12
Pinheiro, Helder Fleury 1967. "The application of Trefftz-FLAME to electromagnetic wave problems /." Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=115703.
Full textAbstract:
Numerical analysis of the electromagnetic fields in large, complex structures is very challenging due to the high computational overhead. Recently, it has been shown that a new method called Trefftz-FLAME ( Flexible Local Approximation MEthod) is suitable for problems where there exist a large number of similar structures.This thesis develops Trefftz-FLAME in two areas. First, a novel 2D Trefftz-FLAME method incorporates the modal analysis and port boundary condition that are essential to an accurate calculation of reflection and transmission coefficients for photonic crystal devices. The new technique outperforms existing methods in both accuracy and computational cost.
The second area pertains to the 3D, vector problem of electromagnetic wave scattering by aggregates of identical dielectric particles. A methodology for the development of local basis functions is introduced, applicable to particles of any shape and composition. Boundary conditions on the surface of the finite FLAME domain are described, capable of representing the incident wave and absorbing the outgoing radiation. A series of problems involving dielectric spheres is solved to validate the new method. Comparison with exact solutions is possible in some cases and shows that the method is able to produce accurate near-field results even when the computational grid spacing is equal to the radius of the spheres.
13
Zribi, Habib. "La Méthode des Équations Intégrales pour des Analyses de Sensitivité." Phd thesis, Ecole Polytechnique X, 2005. http://pastel.archives-ouvertes.fr/pastel-00003492.
Full textAbstract:
Dans cette thèse, nous menons à l'aide de la méthode des équations intégrales des analyses de sensitivité de solutions ou de spectres de l'équation de conductivité par rapport aux variations géométriques ou de paramètres de l'équation. En particulier, nous considérons le problème de conductivité dans des milieux à forts contrastes, le problème de perturbation du bord d'une inclusion de conductivité, le problème de valeurs propres du Laplacien dans des domaines perturbés et le problème d'ouverture de gap dans le spectre des cristaux photoniques.
14
Tokode, Oluwatosin. "Photocatalytic destruction of volatile organic compounds from the oil and gas industry." Thesis, Robert Gordon University, 2014. http://hdl.handle.net/10059/1134.
Full textAbstract:
Heterogeneous photocatalysis is an advanced oxidation technology widely applied in environmental remediation processes. It is a relatively safe and affordable technology with a low impact on the environment and has found applications in a number of fields from chemical engineering, construction and microbiology to medicine. It is not catalysis in the real sense of the word as the photons which initiate the desired photocatalytic reaction are consumed in the process. The cost of these photons is by far the limiting economic factor in its application. From a technical standpoint, the inefficient use of the aforementioned photons during the photocatalytic reaction is responsible for the limited adoption of its application in industry. This inefficiency is characterised by low quantum yields or photonic efficiencies during its application. The mechanism of the technique of controlled periodic illumination which was previously proposed as a way of enhancing the low photonic efficiency of TiO2 photocatalysis has been investigated using a novel controlled experimental approach; the results showed no advantage of periodic illumination over continuous illumination at equivalent photon flux. When the technique of controlled periodic illumination is applied in a photocatalytic reaction where attraction between substrate molecules and catalyst surface is maximum and photo-oxidation by surface-trapped holes, {TiIVOH•}+ ads is predominant, photonic efficiency is significantly improved. For immobilized reactors which usually have a lower illuminated surface area per unit volume compared to suspended catalyst and mass transfer limitations, the photonic efficiency is even lower. A novel photocatalytic impeller reactor was designed to investigate photonic efficiency in gas–solid photocatalysis of aromatic volatile organic compounds. The results indicate photonic efficiency is a function of mass transfer and catalyst deactivation rate. The development of future reactors which can optimise the use of photons and maximize photonic efficiency is important for the widespread adoption of heterogeneous photocatalysis by industry.
15
Ounnas, Badreddine. "Étude et optimisations de jets photoniques pour des applications non conventionnelles dans les domaines optique et hyperfréquences." Thesis, Saint-Etienne, 2015. http://www.theses.fr/2015STET4009/document.
Full textAbstract:
Le travail de cette thèse est consacré à l’étude et l’optimisation d’un cas particulier de la diffusion des ondes électromagnétiques. Elle porte plus particulièrement sur un phénomène appelé le « jet photonique ou jet électromagnétique (jet EM)». Il s’agit d’un faisceau de lumière étroit et concentré en champ proche avec des caractéristiques physiques remarquables. Dans ce travail, un guide d’onde terminé par un embout de forme particulière est utilisé pour générer le jet photonique. Cette thèse a pour objectif l’étude, la caractérisation expérimentale et l’optimisation de jets photoniques pour des applications dans le domaine optique et hyperfréquences. Une méthode robuste et rapide a été développée pour calculer le champ électromagnétique généré par un objet diélectrique ou en sortie d’un guide d'onde avec un embout de forme particulière. Elle est basée sur la Méthode d'Equation Intégrale aux Frontière (MEIF) qui utilise la seconde identité Green. La caractérisation expérimentale des jets photoniques a été réalisée dans le domaine micro-ondes à des fréquences autour de 30 GHz. La possibilité de générer un jet simple et double en utilisant un guide d’onde à embout a été montrée expérimentalement et théoriquement par la méthode MEIF. Les jets EM simples et doubles ont été utilisés pour la détection d’objets métalliques de taille plus petite que la longueur d’onde et l'imagerie en champ proche à travers des structures optiquement opaques. Une procédure d’optimisation basée sur le couplage entre la MEIF et les algorithmes génétiques a été mise au point afin de générer des jets photoniques avec des caractéristiques a priori bien définie. Des optimisations des jets photoniques générés par un objet diélectrique et en sortie d’un guide d’onde avec embout ont été effectuées pour la micro-gravure laser et l’imagerie HFThe work of this thesis is devoted to the study and optimization of a particular case of the scattering of electromagnetic waves. Particularly, it is about a phenomenon called the "photonic jet or electromagnetic jet (EM jet)". This is a narrow light beam concentrated in near-field with remarkable physical characteristics. In this work, a waveguide terminated by a tip with special form is used to generate the photonic jet. This thesis performs the electromagnetic modeling, the experimental characterization and the optimization of photonic jets for applications in optic and microwave field. A robust and fast method was developed to calculate the electromagnetic field generated by a dielectric object or by a waveguide terminated with a tip. It is based on the boundary integral equation method (BIEM) which uses the second Green identity. Experimental characterization of photonic jets was conducted in the microwave field around 30 GHz. The ability to generate a single and double EM jet using a tipped waveguide has been shown experimentally and theoretically by BEIM method. The single and double EM jets were used for the detection of metal objects with a size smaller than the wavelength and for imaging through opaque structures in near field. An optimization procedure based on the coupling between the BEIM and genetic algorithms has been developed to generate photonic jets with properties well defined. Optimizations of photonic jets generated by a dielectric object and by a tipped waveguide have been realized for laser micro-etching and RF imaging
16
Tran-Math, Carolyn. "Synthesis of poly(NIPAM-co-vmbpy) microspheres and transition metal monomers for metallopolymeric material construction." Scholarly Commons, 2014. https://scholarlycommons.pacific.edu/uop_etds/271.
Full textAbstract:
Poly-N-isopropylacrylamide (PNIPAM) gels grafted to redox-active metal monomers undergo sudden expansion-contraction activity in response to change in environmental conditions, such as temperature, pH, ion concentration, and oxidation states of the metal. The relevance of these conditions to biological systems has garnered attention for PNIPAM-based polymer as potential biomedical materials. Candidate transition metal monomers containing ruthenium and nickel cores were designed and synthesized for copolymerization with NIPAM and cross-linker methylene-bis-acrylamide in order to attain metallopolymer microspheres with a high percentage of metal incorporation. Synthesis of 4-vinyl-4'-methyl-2,2'-bipyridine (vmbpy) was optimized from literature procedures for usage in the metal-containing monomers. Metal-containing monomers were then synthesized, purified, and characterized using electrospray ionization mass spectrometry (ESI-MS), proton nuclear magnetic resonance ( 1 H-NMR), X-ray diffraction, Ultraviolet-Visible light (UV-Vis) spectroscopy, and spectrofluorometry. While the Ru complex was pure and exhibited interesting photochemical properties, lability of the ligands on the Ni monomers resulted in complication of their synthesis. Polymer microspheres of poly(NIPAM-co-vmbpy), the cross-linked copolymer constructed from NIPAM and vmbpy monomers, were synthesized from modified emulsion polymerization procedures. Experimental setup parameters and conditions—such as the methods of injection of initiator and stirring, the time duration for incubating the emulsion, and the initiation temperature—were varied to assess their influences on the material properties of the final product. The polymers were tested for size and morphological uniformity by dynamic light scattering (DLS) and scanning electron microscopy (SEM). While varying the method of initiator injection had no measurable effect on the product, strong mechanical stirring and incubation of the polymer emulsion for 15-25 minutes at 71 °C procured similar polymer products. Consistent properties ensured the polymers' suitability for further material development. Preliminary morphological and spectroscopic characterization was conducted of metallopolymers made from Ru and Ni grafted to PNIPAM. Metallopolymers containing polypyridyl Ru cores exhibited desirable spectroscopic properties and spherical morphology.
17
Lin, Chunjin. "Modèles mathématiques de la théorie du transfert radiatif." Phd thesis, Université des Sciences et Technologie de Lille - Lille I, 2007. http://tel.archives-ouvertes.fr/tel-00411849.
Full textAbstract:
On s'intéresse dans ce travail à différents modèles de transfert radiatif, décrivant les interactions entre la matière et les photons. Les radiations sont décrites en termes d'énergie et flux d'énergie, dans le cas macroscopique, le flfluide environnant est quant à lui décrit par les équations d'Euler (modèle d'hydrodynamique radiative). Dans le cas microscopique, le champ radiatif est vu comme une collection des photons interagissant avec la matière par des mécanismes d'absorption-émission. Ces mécanismes dépendent des états d'excitation interne et d'ionisation de la matière. On commence par monter l'existence locale de solutions régulières pour un système couplant les équations d'Euler et l'équation du transfert radiatif. Ce système est obtenu à partir du bilan d'énergie et d'impulsion totale. Puis on fait une discussion asymptotique pour ce modèle dans le régime hors équilibre et on obtient un système simple couplant les équations d'Euler et une équation elliptique. On montre l'existence des profifils de choc (réguliers) pour ce système, et la régularité de ces profils en fonction de l'amplitude du choc. Puis on étudie la stabilité asymptotique de ces profifils. Enfifin, on présente une étude d'un système décrivant le champ radiatif et les états internes de la matière. On montre l'existence de solutions pour ce système et on établit rigoureusement la convergence vers l'équilibre statistique. Les résultats théoriques sont illustrés par des simulations numériques.
18
Kalinowski, Ksawery Kajetan. "Parametric interactions in ordered and disordered nonlinear photonic crystals." Phd thesis, 2013. http://hdl.handle.net/1885/155996.
Full textAbstract:
Parametric interactions are one of the oldest studied phenomenon in nonlinear optics. The nonlinear light-matter-light interaction allows one to generate light at any wavelength within the transmission band of a nonlinear crystal. It is known that the efficiency of the harmonic generation process strongly depends on the phase mismatch between interacting waves and, in order to observe harmonic generation, some technique has to be implemented. The spatially periodic modulation of the sign of nonlinearity is one of the solutions to this phase mismatch problem. Such structures, called nonlinear photonic crystals, are nowadays widely realized. Proper design of the nonlinearity modulation gives one a great control over the properties of a newly generated harmonic. The purpose of this thesis is the theoretical analysis of possible phase matching schemes and the experimental investigation of nonlinear scattering processes. The nonlinear structures under consideration in this work are periodic and strongly disordered 1D nonlinear gratings; 2D random nonlinear photonic crystals; and a single boundary between two regions of different nonlinearity. Chapter 1 provides a general introduction to aspects of frequency conversion relevant to the topic of this thesis. Basic terms used in quadratic parametric processes are defined. The fundamental theory of harmonic generation in nonlinear crystals is presented. Phase matching techniques in homogeneous and periodic structures are reviewed followed by an introduction to nonlinear diffraction mechanisms in one and two dimensional nonlinear gratings. Chapter 2 contains a theoretical study of parametric wave interaction in nonlinear optical media with a randomized distribution of quadratic nonlinearity. In particular, it shows how the transition from an ideal periodic structure to a fully random structure affects properties of the second and cascaded third harmonic generation. Analytical formulas describing properties of such harmonics in the presence of nonlinearity disorder are derived. In chapter 3 we study theoretically and numerically the second harmonic generation in a two dimensional nonlinear crystal with a random distribution of ferroelectric domains. We numerically generate a disordered structure composed of semi-circular ferroelectric domains of random size and random position. Aside from presenting numerical simulations, we show that the strict model presented in chapter 2 can be successfully applied to 2D random structures. We show that the specific features of disordered domain structures greatly affect the emission pattern of the generated harmonics. In chapter 4 and chapter 5 we study, experimentally and theoretically, the Cerenkov-type second-harmonic generation in a one-dimensional nonlinear photonic crystal. We demonstrate that the power of emitted second-harmonic can be enhanced by varying the angle of incidence of the fundamental beam such that the reciprocal lattice vectors of the crystal can be used to compensate for the phase mismatch in the transverse direction. We also experimentally investigate the Cerenkov second harmonic tuning response to a wavelength and the position of the incident beam. We reveal that, in contrast to the classic second harmonic generation whose tuning response is determined by the superlattice itself, the sensitivity of the Cerenkov harmonic intensity depends strongly on the width of the incident beam.
19
Tong, Jian. "Active optical filters based integrated photonic circuits /." 2006. http://proquest.umi.com/pqdweb?did=1225139861&sid=1&Fmt=2&clientId=10361&RQT=309&VName=PQD.
Full text
20
Richter, Markus [Verfasser]. "Optimization of photonic band structures / von Markus Richter." 2010. http://d-nb.info/1009590634/34.
Full text
21
Krämer, Axel [Verfasser]. "Adaptivity in bandstructure calculations of photonic crystals / Axel Krämer." 2011. http://d-nb.info/1012826570/34.
Full text
22
Bulovyatova, Tatiana [Verfasser]. "Numerical methods of localization of Wannier functions in modeling of photonic cCrystals / von Tatiana Bulovyatova." 2011. http://d-nb.info/1011236206/34.
Full text
23
"Disentanglement dynamics of photons in noisy environment." 2008. http://library.cuhk.edu.hk/record=b5896849.
Full textAbstract:
Poon, Sin Yau = 光子在噪聲環境中的解糾纏 / 潘善柔.Thesis (M.Phil.)--Chinese University of Hong Kong, 2008.
Includes bibliographical references (leaves 101-110).
Abstracts in English and Chinese.
Poon, Sin Yau = Guang zi zai zao sheng huan jing zhong de jie jiu chan / Pan Shanrou.
Chapter 1 --- Introduction --- p.1
Chapter 2 --- Review on entanglement theory --- p.4
Chapter 2.1 --- Pure state entanglement --- p.4
Chapter 2.2 --- Mixed state entanglement --- p.7
Chapter 2.3 --- Positive partial transposition (PPT) criterion --- p.9
Chapter 2.4 --- Negativity of pTA --- p.9
Chapter 2.4.1 --- Basic properties --- p.10
Chapter 2.4.2 --- Comparison with concurrence --- p.11
Chapter 2.5 --- Entanglement witness --- p.12
Chapter 2.6 --- Inseparability criterion based on uncertainty relations --- p.13
Chapter 2.7 --- Limitations of the PPT criterion --- p.14
Chapter 2.8 --- Other manifestations of entanglement --- p.16
Chapter 2.8.1 --- Non-classicality by negative P-representation --- p.16
Chapter 2.8.2 --- Non-locality by violation of Bell´ةs inequality --- p.17
Chapter 3 --- Quantum decoherence: General considerations for open systems --- p.22
Chapter 3.1 --- A master equation approach --- p.22
Chapter 3.1.1 --- Master equation in Markovian channels --- p.25
Chapter 3.2 --- Negativity as a monotone in Markovian systems --- p.26
Chapter 3.3 --- Finite time disentanglement --- p.29
Chapter 3.4 --- Non-classicality of harmonic oscillating systems in finite temperature baths --- p.32
Chapter 4 --- Disentanglement dynamics of two-mode Gaussian states --- p.36
Chapter 4.1 --- Two-mode Gaussian states: General descriptions --- p.36
Chapter 4.1.1 --- Covariance matrices and symplectic eigenvalues --- p.37
Chapter 4.1.2 --- Squeezed states as a source of entanglement --- p.39
Chapter 4.2 --- Eigenvalues and eigenvectors of pTA --- p.41
Chapter 4.3 --- Physical interpretation of negativity --- p.43
Chapter 4.4 --- Disentanglement of two-mode squeezed states in damping and amplifying environment --- p.47
Chapter 4.4.1 --- Block structures of pTA in Fock space --- p.47
Chapter 4.4.2 --- Analytic solution of p in position space --- p.49
Chapter 4.4.3 --- Evolution of eigenvalues and eigenvectors of pTA --- p.51
Chapter 4.4.4 --- Robust structure of entanglement witness --- p.56
Chapter 4.5 --- Beam splitter as a model for thermal damping of initial Gaussian states --- p.59
Chapter 4.6 --- Evolution of entanglement of a damped parametric oscillator --- p.63
Chapter 4.6.1 --- Eigenvalues and Eigenvectors of pTA --- p.64
Chapter 4.6.2 --- Negativity and sub-negativity --- p.66
Chapter 4.7 --- Dissipation in baths with both amplitude and phase damping --- p.68
Chapter 4.8 --- Loss of nonlocality: An optimized Bell's inequality approach --- p.69
Chapter 5 --- Disentanglement via polarization mode dispersion --- p.73
Chapter 5.1 --- Review on polarization mode dispersion --- p.73
Chapter 5.2 --- A model for stochastic polarization mode dispersion --- p.75
Chapter 5.3 --- General description of two-photon states --- p.78
Chapter 5.4 --- Disentanglement of two-photon states in separate fibers --- p.81
Chapter 5.4.1 --- Polarization negativity and frequency negativity --- p.83
Chapter 5.4.2 --- Polarization disentanglement --- p.84
Chapter 5.4.3 --- Frequency disentanglement --- p.85
Chapter 5.5 --- Disentanglement of two-photon states in a common fiber --- p.86
Chapter 5.5.1 --- Polarization disentanglement of the singlet state --- p.90
Chapter 5.5.2 --- Frequency entanglement of the singlet state --- p.91
Chapter 5.6 --- Non-Markovian channels --- p.92
Chapter 6 --- Conclusion --- p.99
Bibliography --- p.101
Chapter A --- CHSH Inequality for bipartite two level systems --- p.111
Chapter B --- Transformation from general two-mode Gaussian to double Gaussian product --- p.113
Chapter C --- Time evolution of general real symmetric two-mode Gaussian density operator --- p.116
Chapter D --- Time evolution of a damped parametric oscillator --- p.119
Chapter E --- Optimal Bell values for a damped TMSV in pseudo-spin formalism --- p.123
Chapter F --- Derivation of master equation for two-photon states --- p.125
Chapter G --- Solution of master equation for two-photon states --- p.127
Chapter G.1 --- Evolution of two-photon states in separate fibers --- p.127
Chapter G.2 --- Evolution of two-photon state in a common fiber --- p.129
24
Bulovyatov, Alexander [Verfasser]. "A parallel multigrid method for band structure computation of 3D photonic crystals with higher order finite elements / von Alexander Bulovyatov." 2010. http://d-nb.info/1003331718/34.
Full text
25
Nicholas, Michael J. "A Third Order Numerical Method for Doubly Periodic Electromegnetic Scattering." Diss., 2007. http://hdl.handle.net/10161/383.
Full text
26
"Generalized Jayne[sic]-Cummings models without the rotating wave approximation =: 廣義 Jaynes-Cummings 模型及其反旋轉項之效應." 1997. http://library.cuhk.edu.hk/record=b5889256.
Full textAbstract:
Ng Kin Man.Thesis (M.Phil.)--Chinese University of Hong Kong, 1997.
Includes bibliographical references (leaves 186-189).
Ng Kin Man.
Contents --- p.i
List of Figures --- p.ii
Abstract --- p.iv
Acknowledgement --- p.v
Chapter Chapter 1. --- Introduction --- p.1
Chapter 1.1 --- Introduction --- p.1
Chapter 1.2 --- Objective and Methodology --- p.3
Chapter Chapter 2. --- Theory of the Jaynes-Cummings model --- p.6
Chapter 2.1 --- Formulation of the Problem --- p.6
Chapter 2.1.1 --- Quantization of the Electromagnetic Field --- p.7
Chapter 2.1.2 --- Quantization of the Matter Field --- p.11
Chapter 2.1.3 --- The Interaction between the Radiation and the Matter --- p.12
Chapter 2.1.4 --- Formulation of the one-photon JCM --- p.14
Chapter 2.2 --- Eenergy eigenstates and Eigenvalue Spectrum --- p.16
Chapter 2.3 --- Dynamics of the one-photon JCM --- p.18
Chapter 2.3.1 --- The time evolution of the system --- p.19
Chapter 2.3.2 --- Atomic Observables --- p.20
Chapter 2.3.3 --- Field Observables --- p.23
Chapter 2.4 --- Asymptotic solution of the JCM --- p.27
Chapter 2.5 --- Discussion of the role of the RWA in the JCM --- p.29
Chapter 2.6 --- Conclusion --- p.30
Chapter Chapter 3. --- Numerical Results for the one-photon JCM --- p.40
Chapter 3.1 --- Eigenstates and Eigenvalue Spectrum --- p.40
Chapter 3.2 --- Dynamics of the System --- p.44
Chapter 3.2.1 --- Atomic Observables --- p.44
Chapter 3.2.2 --- Field Observables --- p.45
Chapter 3.3 --- Conclusion --- p.47
Chapter Chapter 4. --- Generalization of the JCM --- p.60
Chapter 4.1 --- Multiphoton JCM --- p.60
Chapter 4.2 --- Intensity-dependent JCM --- p.62
Chapter 4.3 --- Two-mode two-photon JCM --- p.64
Chapter 4.4 --- Conclusion --- p.66
Chapter Chapter 5. --- Multiphoton Jaynes-Cummings model --- p.67
Chapter 5.1 --- Energy Eigenstates and Eigenvalue Spectrum --- p.67
Chapter 5.1.1 --- Energy Eigenstates and Eigenvalue Spectrum of the two- photon JCM --- p.71
Chapter 5.1.2 --- Eigenstates and Eigenvalue Spectrum for the k-photon JCM with k>2 --- p.73
Chapter 5.2 --- Dynamics of the two-photon JCM --- p.75
Chapter 5.2.1 --- Atomic Observables --- p.75
Chapter 5.2.2 --- Field Observables --- p.77
Chapter 5.3 --- Conclusion --- p.84
Chapter Chapter 6. --- Intensity-dependent Jaynes-Cummings model --- p.107
Chapter 6.1 --- Eigenstates and Eigenvalue Spectrum --- p.107
Chapter 6.1.1 --- Energy Eigenstates and Eigenvalue Spectrum of the one- photon intensity-dependent JCM --- p.110
Chapter 6.1.2 --- "Energy Eigenstates and Eigenvalue Spectrum for the k-photon intensity-dependent, JCM with k > 1" --- p.113
Chapter 6.2 --- Dynamics of the one-photon intensity-dependent JCM --- p.115
Chapter 6.2.1 --- Atomic Observables --- p.115
Chapter 6.2.2 --- Field Observables --- p.116
Chapter 6.3 --- Conclusion --- p.123
Chapter Chapter 7. --- Two-mode Two-photon Jaynes- Cummings model --- p.148
Chapter 7.1 --- Eigenstates and Eigenvalue Spectrum --- p.148
Chapter 7.2 --- Dynamics of the System --- p.156
Chapter 7.2.1 --- Atomic Observables --- p.156
Chapter 7.2.2 --- Field Observables --- p.160
Chapter 7.3 --- Conclusion --- p.161
Chapter Chapter 8. --- Conclusion --- p.183
Bibliography --- p.186
27
Law, Kody John Hoffman. "Existence, Stability, and Dynamics of Solitary Waves in Nonlinear Schroedinger Models with Periodic Potentials." 2010. https://scholarworks.umass.edu/open_access_dissertations/179.
Full textAbstract:
The focus of this dissertation is the existence, stability, and resulting dynamical evolution of localized stationary solutions to Nonlinear Schr¨odinger (NLS) equations with periodic confining potentials in 2(+1) dimensions. I will make predictions about these properties based on a discrete lattice model of coupled ordinary differential equations with the appropriate symmetry. The latter has been justified by Wannier function expansions in a so-called tight-binding approximation in the appropriate parametric regime. Numerical results for the full 2(+1)-D continuum model will be qualitatively compared with discrete model predictions as well as with nonlinear optics experiments in optically induced photonic lattices in photorefractive crystals. The predictions are also relevant for BECs (Bose-Einstein Condensates) in optical lattices.
28
Hayek, Wolfgang-Simon. "Photon scattering 3D radiation-hydrodynamical simulations of late-type stellar atmospheres." Phd thesis, 2010. http://hdl.handle.net/1885/150108.
Full textAbstract:
Numerical models of stellar atmospheres fulfill an important role in astrophysical research. They describe the physical environment from which stellar radiation originates, allowing detailed analyses of the temperature and pressure stratification in the atmosphere, of the chemical composition, atmospheric motion, phenomena related to magnetic fields and more. Theoretical studies of stellar atmospheres usually involve two steps: first, the model atmosphere is constructed according to a set of parameters. Based on this model, a theoretical representation of an observable is produced, e.g., spectral lines or the center-to-limb variation of continuum radiation. 3D time-dependent radiation-hydrodynamical simulations of stellar atmospheres have been very successful in reproducing observations and have become a viable tool for solar physics and stellar astrophysics. Coupling detailed radiative transfer with a hydrodynamical description of stellar surface granulation, they allow accurate predictions of the atmospheric stratification, velocity fields, spectral line formation, magnetic phenomena etc. The complexity and computational effort of 3D radiation-hydrodynamical simulations requires a variety of approximations, such as the assumption of local thermodynamic equilibrium (LTE) in the treatment of radiative transfer. This PhD thesis explores the enhancement of the radiation model with coherent photon scattering, studying its importance for radiative heating in 3D radiation-hydrodynamical simulations. By comparing the atmospheric temperature stratification derived from different treatments of scattering opacity, it is demonstrated that a solar-type photosphere is well-approximated when continuum scattering is treated as absorption, while this approach leads to significantly higher temperatures above the photosphere if applied to line-blanketing. In metal-poor giants, Rayleigh scattering is an important continuous opacity source; treating the opacity as absorption leads to significantly higher temperatures above the surface and a shallower temperature gradient. The temperature structure of the model atmosphere with coherent scattering can be approximated with reasonable accuracy by removing scattering opacity above the stellar surface and using a Planck source function, which largely reduces the computational effort. 3D spectral line formation is an essential diagnostic for simulations of stellar atmospheres, and a widely used tool for analyzing, e.g., the chemical composition of stars. Metal-poor giants are interesting astrophysical laboratories in this context, for studying the chemical evolution of the Galaxy and the origin of the elements. The second part of the thesis investigates LTE spectral line formation with continuum scattering in metal-poor giants. It is shown that an increasing thermalization depth through scattering at short wavelengths affects profile shapes and equivalent widths, with important consequences for measured abundances.
29
Mahmoudi, Farvah. "Chromodynamique Quantique aux collisionneurs hadroniques : Vers une automatisation du calcul des processus multi-particules à l'ordre d'une boucle. Application à la production de deux photons et d'un jet." Phd thesis, 2004. http://tel.archives-ouvertes.fr/tel-00006725.
Full textAbstract:
Le futur collisionneur du CERN (le LHC) possède un fantastique potentiel de découverte à condition d'avoir une prédiction quantitative de la QCD. Pour ce faire, il est nécessaire d'effectuer des calculs dans l'approximation NLO de manière à réduire la dépendance de la section efficace en fonction des échelles non physiques. Pour obtenir des résultats dans cette approximation, il faut calculer les sections efficaces des sous-processus partoniques contribuant à la réaction étudiée à l'ordre le plus bas ainsi que les corrections virtuelles (une boucle) et réelles. Le calcul des corrections virtuelles reste très compliqué si le nombre de particules externes est supérieur à quatre ou si les particules externes (internes) sont massives.Dans cette thèse est proposée une méthode automatique pour effectuer les calculs à une boucle et à cinq pattes, et qui peut être généralisée aux cas de particules massives.
Dans une première partie, nous décrirons divers outils et méthodes nécessaires à de tels calculs. Nous les appliquerons ensuite au calcul de la réaction (gluon + gluon -> photon + photon + gluon), qui intéresse les expérimentateurs des expériences ATLAS et CMS comme bruit de fond à la recherche du Higgs, notamment pour décrire correctement la queue de la distribution transverse du boson de Higgs. Sera alors présenté le résultat explicite de cette amplitude pour chaque configuration d'hélicités sous une forme compacte et une représentation clairement invariante de jauge. Nous terminerons par une étude phénoménologique de cette réaction.
30
Madhav, Kalaga Venu. "All-Fiber Sensing Techniques For Structural Health Monitoring And Other Applications." Thesis, 2007. http://hdl.handle.net/2005/644.
Full textAbstract:
In this thesis, we explore the four aspects of fiber Bragg grating sensors: mathematical modeling of Fiber Bragg Grating response/spectral characteristics, fabrication using phase mask, application and interrogation. Applications of fiber Bragg gratings, also known as in-fiber gratings, with emphasis on their sensing capabilities, interrogation of an array of sensors and their performance in structural health monitoring scenario are documented.
First, we study the process of photosensitivity phenomenon in glasses, in particular GeO2:SiO2 glasses. For mathematical modeling we consider the 1-D refractive index profile along the propagation axis of an optical fiber drawn from the preform of such glasses. These 1-D index structures exhibit a bandgap for propagation along the fiber axis. We show how the bandgap is dependent on the two structural parameters: index periodicity and effective refractive index. The mathematical model provides the characteristics of three sensor parameters -resonance wavelength also known as the Bragg wavelength (λB ), filter bandwidth (ΔλB ), and reflectivity (R). We show that the evolution of the index structure in germanosilicate glasses is dependent on the inscription parameters such as exposure time, intensity of the laser used for inscribing, the interference pattern, and coherence of the laser system. In particular, a phase mask is used as the diffffacting element to generate the required interference pattern, that is exposed on the photosensitive fiber. We present a mathematical model of the electromagnetic diffraction pattern behind the phase mask and study the effect of the limited coherence of the writing laser on the interference pattern produced by the diffracting beams from the mask.
Next, we demostrate the sensing capabilities of the fiber Bragg gratings for measuring strain, temperature and magnetic fields. We report linearity of 99.7% and sensitivity of 10.35pm/◦C for the grating temperature sensor. An array of gratings assigned with non-overlapping spectral windows is inscribed in a single fiber and applied for distributed sensing of structural health monitoring of an aircraft’s composite air-brake panel. The performance of these sensors is compared with the industry standard resistance foil gauges. We report good agreement between the two gauges (FBG and RSG).
In some applications it is more desirable to know the spectral content, rather than the magnitude of perturbation. Fiber Bragg gratings sensors can be used to track events that occur in a very small span of time and contain high frequencies. Such applications demand very high speed wavelength demodulation methods. We present two interrogation techniques: wavelength-shift time-stamping (WSTS) and reflectivity division multiplexing (RDM). WSTS interrogation method employs the multiple threshold-crossing technique to quantize the sensor grating fluctuations and in the process produces the time stamps at every level-cross. The time-stamps are assembled and with the a priori knowledge of the threshold levels, the strain signal is reconstructed. The RDM methodology is an extension of the WSTS model to address multiple sensors. We show that by assigning unique reflectivities to each of the sensors in an array, the time-stamps from each of the sensors can be tagged. The time-stamps are collected by virtue of their corresponding pulse heights, and assembled to reconstruct the strain signal of each of the array sensor. We demonstrate that the two interrogation techniques are self-referencing systems, i.e., the speed at which the signals are reconstructed is instantaneous or as fast as the signal itself.