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AMARAL, Anderson Monteiro. "Transverse optical phenomena with Gaussian beams and optical vortices". Universidade Federal de Pernambuco, 2016. https://repositorio.ufpe.br/handle/123456789/18646.
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CNPQ
In this thesis are presented various results regarding the transverse structure of light beams in the paraxial propagation regime, with a special concern with singularities in the transverse profile and in nonlinear optics applications. Theoretical and experimental tools were developed for the study of Optical Vortices (OV) and its most important characteristics, as the Orbital Angular Momentum (OAM) and the Topological Charge (TC). In a first step, we theoretically described and experimentally demonstrated that it is possible to shape the intensity profile of a beam containing OV by distributing TC over the plane transverse to the propagation direction [1]. The TC is associated with a phase singularity that implies in points of zero intensity. By distributing the TC on the transverse plane, it is possible to shape the beam dark region and also the OAM profile with the goal of optimizing the light beam for a given application. However, a problem identified in [1] was that most of the current available techniques to characterize OAM light implicitly assume that the beam has cylindrical symmetry, thus being inadequate to characterize fields resulting from more general TC distributions. These problems were approached in a second work [2], where it was shown that by measuring the field transverse amplitude and phase profiles it is possible to measure the OAM and the TC in TC distributions with arbitrary geometries. By combination of the results [1] and [2] it is possible to optimize and characterize the TC distributions for given applications, as for example by designing the transverse forces in an optical tweezer for microparticle manipulation. An important theoretical unfold during these works was the identification of an analogous relation between the field transverse phase in a TC distribution with the Coulomb potential in two-dimensional electrostatics. We then introduced in [3] the Topological Potential (TP) concept which allows the design of structured optical beams with complex spatial profiles inspired by two-dimensional electrostatics analogies. The TP can be used to describe a broad class of TC distributions, as those from [1,2] or the more sophisticate examples in [3]. In another set of results, it is discussed the possibility of using concepts and the formalism of quantum mechanics to solve light propagation problems in the classical approximation. Among the results obtained, it should be remarked that the formalism obtained has a simple and direct relation with ABCD matrices and ray optics [4]. These results were used to understand light propagation in systems containing nonlinear materials, as in SLIM [5] and D4σ [6] techniques. In [5, 6] the theoretical results were compared with experimental data obtained from standard samples, as carbon dissulfide (CS2), acetone and fused silica. It was obtained a very good agreement between the measured optical nonlinearities and the results established in literature for these materials.
Nesta tese são apresentados resultados relacionados com a estrutura transversal de feixes de luz no regime paraxial de propagação, com uma atenção especial em singularidades no perfil transversal e em aplicações para óptica não linear. Foram desenvolvidas ferramentas teóricas e experimentais para o estudo de vórtices ópticos (Optical Vortices - OVs), e suas características mais importantes, como o momento angular orbital (Orbital Angular Momentum - OAM) e a carga topológica (Topological Charge - TC). Inicialmente, foi teoricamente descrito e experimentalmente demonstrado como é possível moldar o perfil de intensidade de um feixe contendo OVs usando uma distribuição de TC sobre o plano transversal à direção de propagação [1]. A TC está associada a uma singularidade na fase, o que implica em um zero de intensidade. Ao se distribuir a TC sobre o plano transversal, é possível moldar o formato da região de intensidade nula e também o perfil de OAM no intuito de otimizar o feixe para uma dada aplicação. No entanto, um problema identificado neste trabalho é que a maior parte das técnicas de caracterização disponíveis para luz com OAM implicitamente supunham que o feixe possui simetria cilíndrica, e portanto não eram adequadas para caracterizar campos obtidos a partir de distribuições de TC com geometrias mais gerais. Tais problemas foram abordados em um segundo trabalho [2], onde foi mostrado que por meio de medições dos perfis transversais de amplitude e fase do campo elétrico é possível medir o OAM e a TC em distribuições de TC com formas geométricas arbitrárias. A união dos trabalhos [1] e [2] permite então que as distribuições de TC possam ser adequadamente otimizadas e caracterizadas para aplicações específicas, como por exemplo ao moldar as forças transversais numa pinça óptica para a manipulação de micropartículas. Um desdobramento teórico importante obtido foi identificar uma relação análoga entre o perfil de fase em uma distribuição de TC com o potencial de Coulomb em eletrostática bidimensional. Foi então introduzido em [3] o conceito de potencial topológico (Topological Potential - TP) que possibilita a construção de feixes ópticos estruturados com perfis espaciais complexos inspirados em analogias com eletrostática bidimensional. O TP pode ser usado na descrição de uma grande variedade de distribuições de TC, como nos feixes em [1, 2] ou nos exemplos mais sofisticados em [3]. Posteriormente, é discutida a possibilidade de se utilizar conceitos e o formalismo da mecânica quântica na solução de problemas de propagação da luz descrita na aproximação clássica. Dentre os resultados obtidos, destaca-se que o formalismo possui uma relação simples e direta com as matrizes ABCD e a óptica de raios [4]. Estes resultados foram utilizados na compreensão da propagação da luz em sistemas contendo materiais não lineares, como nas técnicas SLIM [5] e D4σ[6]. Nos trabalhos [5,6] os resultados teóricos foram comparados com dados experimentais obtidos em amostras padrão, como dissulfeto de carbono (CS2), acetona e sílica fundida. Foi obtida uma concordância muito boa entre os valores medidos para as não linearidades ópticas nestes materiais e os valores estabelecidos na literatura.
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Taylor, Jonathan Midgley. "Optical binding phenomena : observations and mechanisms". Thesis, Durham University, 2009. http://etheses.dur.ac.uk/54/.
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Novel results on the optical binding of optically-trapped micro-particles are presented. A sophisticated Mie scattering model is developed, capable of performing time-evolution simulations of a multi-particle system. This is used to analyse and interpret experimental results in evanescent and Gaussian beam traps, and to develop simple, intuitive explanations for the observed phenomena. Novel trapped states are reported, that do not conform to the symmetry of the underlying trap. A common theme throughout this thesis is the "emergent'' phenomena that occur when multiple particles are trapped together, which cannot easily be predicted by considering each particle in isolation.
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Pester, Paul D. "Optical beam induced phenomena in semiconductors". Thesis, University of Oxford, 1988. http://ora.ox.ac.uk/objects/uuid:a02591ee-1600-4c9c-ab19-30447edc07da.
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This thesis is concerned with the interaction of a finely focussed light beam and a semiconductor. The object of the work is to develop a consistent theory which explains the formation of both the optical beam induced current and photoluminescence signals with a view to using these techniques to characterize semiconductor materials. Here we extend previous theories by considering a light beam which is focussed through a lens of finite numerical aperture. Expressions are derived which give the distribution of excess minority carriers injected into a semi-infinite semiconductor by the focussed light beam. The injected minority carrier distribution is then used to predict the imaging properties of the optical beam induced current and photoluminescence techniques when used to image electrically active defects in semiconductors. High resolution scanning photoluminescence images of indium phosphide are presented showing a resolution which is in good agreement with theory. The form of both the steady state and time dependent optical beam induced current in Schottky barrier diodes, planar junction diodes and devices where the p-n junction is perpendicular to the semiconductor surface is derived. Various methods are suggested for measuring the minority carrier diffusion length and lifetime. An extension to previous analyses is given by considering the effect of scanning the light beam, at some arbitrary velocity, on the form of the optical beam induced current collected by a p-n junction either parrallel or perpendicular to the semiconductor surface. It is also shown how the scan speed can effect the imaging of electrically active defects producing a contrast function which is asymmetric and reduced in magnitude. An analysis of the photoluminescence signal generated from a semi-infinite semiconductor by a finely focussed light beam is given. Various methods based on the photoluminescence technique are suggested for measuring the minority carrier lifetime.
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FORTENBERRY, RANCE MORGAN. "NONLINEAR OPTICAL PHENOMENA IN ZINC OXIDE WAVEGUIDES (INTEGRATED OPTICS, NONLINEAR COUPLING)". Diss., The University of Arizona, 1986. http://hdl.handle.net/10150/183951.
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This dissertation reports on the development of a nonlinear surface spectroscopy and the observation of nonlinear optical phenomena using sputtered zinc oxide waveguides. The first is known as Surface Coherent Raman Spectroscopy, or SCRS, and is capable of monolayer sensitivity. The second, discovered during the development of SCRS, is optical limiting and a previously unobserved form of optical switching based on an absorptive nonlinear coupling mechanism. Overviews of the theories of waveguiding, linear coupling, and SCRS are given. Experiments showing that the spectrum of a monolayer coverage of molecules on the surface of a metal oxide waveguide can be obtained using SCRS are reported. For this purpose ZnO waveguides were fabricated using rf magnetron sputtering; the details of which are presented. The results of the characterization of these films, using an optical loss technique, Rutherford backscattering, and X-ray diffraction, are also presented. Experiments are described and data are presented to show the existence of optical limiting and optical switching phenomena in ZnO waveguides. The experimental dependence of these phenomena on input pulse energy, wavelength, temporal pulse width, and type of distributed coupling mechanism is described. Existing nonlinear distributed coupler theory is extended to include the effect of an absorptive nonlinearity and the results of this theory are used to explain some of the characteristic features of the experimental results. A value of n₂ ≅ 2 x 10⁻¹⁶ m²/W for the nonlinear coefficient of sputtered ZnO films is obtained.
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Fameli, Nicola. "Optical studies of critical phenomena in fluids". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/NQ56538.pdf.
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Vázquez, Lozano Juan Enrique. "Spin-Dependent Optical Phenomena: Fundamentals and Applications". Doctoral thesis, Universitat Politècnica de València, 2021. http://hdl.handle.net/10251/166775.
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[ES] Al igual que la masa o la carga, el espín es una propiedad física fundamental que, típicamente, aparece en la descripción de los sistemas cuánticos. Más allá de sus importantes implicaciones teóricas, el creciente avance de la tecnología y el desarrollo de los dispositivos hacia escalas cada vez más pequeñas ha favorecido el surgimiento de multitud de aplicaciones que involucran al espín, entre las cuales se destaca la espintrónica; una nueva forma de electrónica en la que, además de la carga, también se explotan los grados de libertad otorgados por el espín del electrón. Por supuesto, el espín no es exclusivo de los electrones, está presente en todas las partículas elementales, y por ende, en los fotones. En este caso, y a diferencia de lo que ocurre con los electrones, existe una correspondencia clásica que relaciona el espín del fotón con los estados de polarización circular de la luz. Por lo tanto, en nano-óptica y en fotónica, los fenómenos basados en el espín se refieren, grosso modo, a aquellos que son fuertemente dependientes de la polarización circular de la luz. En este marco general, uno de los ejemplos más preponderantes se halla en la interacción espín-órbita. En su versión óptica establece que, bajo ciertas condiciones, es posible que exista una influencia mutua entre el estado de polarización (espín) y la propagación (órbita) de la luz. A pesar de su carácter ubicuo en todos los procesos ópticos básicos, sus efectos son muy débiles, y su manifestación se restringe a la nanoescala, lo cual dificulta su observación e identificación. En este mismo contexto, otro concepto heredado del formalismo cuántico que tiene análogo fotónico directo es la quiralidad óptica; una propiedad dinámica local que, de alguna manera, permite cuantificar escalarmente el espín de un campo óptico. Aparte de su controvertido significado físico y su estrecho vínculo con los sistemas plasmónicos y los metamateriales, como amplificadores de sus efectos, su principal característica fundamental es que, para los campos ópticos en el vacío, es una cantidad conservada. En esta tesis se ahonda teóricamente en los fundamentos básicos de estas características fotónicas. Específicamente, se demuestra analíticamente que la interacción espín-órbita es un fenómeno que surge natural y necesariamente en la nanoescala. Sobre esta base se expone un formalismo para extender la excitación unidireccional de campo cercano más allá de la aproximación dipolar, lo cual facilita su observación y mejora las propiedades de acoplo. Por otra parte, se analiza el concepto de la quiralidad óptica, originalmente definida en el vacío, y se generaliza a cualquier tipo de medio, incluyendo sistemas altamente dispersivos. Asimismo, se exploran diferentes configuraciones que permitan implementar las principales funcionalidades quirópticas (sensado y espectroscopía) en plataformas de fotónica integrada. Además de su potencial para aplicaciones, este estudio tiende un puente para abordar clásicamente propiedades y efectos que tradicionalmente son de tipo cuántico.[CA] Igual que la massa o la càrrega, l'espín és una propietat física fonamental que, típicament, apareix en la descripció dels sistemes quàntics. Més enllà de les seves importants implicacions teòriques, el creixent avanç de la tecnologia i el desenvolupament dels dispositius cap a escales cada vegada més petites ha afavorit el sorgiment de multitud d'aplicacions que involucren l'espín, entre les quals es destaca l'espintrònica; una nova forma d'electrònica en què, a més de la càrrega, també s'exploten els graus de llibertat atorgats per l'espín de l'electró. Per descomptat, l'espín no és exclusiu dels electrons, és present en totes les partícules elementals, i per tant, en els fotons. En aquest cas, i a diferència del que passa amb els electrons, hi ha una correspondència clàssica que relaciona l'espín del fotó amb els estats de polarització circular de la llum. Per tant, en nano-òptica i en fotònica, els fenòmens basats en l'espín es refereixen, grosso modo, a aquells que són fortament dependents de la polarització circular de la llum. En aquest marc general, un dels exemples més preponderants es troba en la interacció espín-òrbita. En la seva versió òptica estableix que, sota certes condicions, és possible que hi hagi una influència mútua entre l'estat de polarització (espín) i la propagació (òrbita) de la llum. Malgrat el seu caràcter ubic en tots els processos òptics bàsics, els seus efectes són molt febles, i la seva manifestació es restringeix a la nanoescala, la qual cosa dificulta la seva observació i identificació. En aquest mateix context, un altre concepte heretat del formalisme quàntic que té anàleg fotònic directe és la quiralitat òptica; una propietat dinàmica local que, d'alguna manera, quantifica escalarment l'espín d'un camp òptic. A banda del seu controvertit significat físic i el seu estret vincle amb els sistemes plasmònics i els metamaterials, com amplificadors dels seus efectes, la seva principal característica fonamental és que, per als camps òptics en el buit, és una quantitat conservada. Des d'un enfocament teòric, aquesta tesi aprofundeix en els fonaments bàsics d'aquestes característiques fotòniques. Específicament, es demostra analíticament que la interacció espín-òrbita és un fenomen que sorgeix natural i necessàriament en la nanoescala. Sobre aquesta base s'exposa un formalisme per estendre l'efecte d'excitació unidireccional de camp pròxim més enllà de l'aproximació dipolar, la qual cosa facilita la seva observació i millora les propietats d'acoblo. D'altra banda, s'analitza el concepte de la quiralitat òptica, originalment definida en el buit, i es generalitza a qualsevol tipus de mitjà, incloent sistemes altament dispersius. Així mateix, s'exploren diferents configuracions que permetin implementar les principals funcionalitats quiròptiques (sensat i espectroscòpia) en plataformes de fotònica integrada. A més del seu potencial per a aplicacions, aquest estudi tendeix un pont per abordar clàssicament propietats i efectes tradicionalment quàntics.
[EN] Just like mass or charge, spin is a fundamental physical property that, typically, appears in the description of quantum systems. Beyond its important theoretical implications, the rapid advance of technology along with the relentless trend toward the development of devices at increasingly smaller scales have boosted the occurrence of a wide range of applications involving spin, among which is highlighted the spintronics; a novel form of electronics which, besides the charge, also exploits the degrees of freedom provided by the electron spin. Of course, the spin is not exclusive to electrons, but is actually present in all the elementary particles, and therefore in photons. In such a case, and unlike what happens with electrons, there exists a direct classical correspondence relating the spin of photons with the circular polarization states of light. Thus, in nano-optics and photonics, spin-dependent phenomena are broadly referred to as those that strongly rely upon the circular polarization of light. Within this general framework, one of the most preponderant examples is found in the spin-orbit interaction. In its optical version, it states that, under certain conditions, it is possible that there exists a mutual influence between the state of polarization (spin) and the propagation (orbit) of light. Despite its ubiquitous character in all basic optical processes, its effects are very weak, and its manifestation is restricted at the nanoscale, thereby hindering its observation and identification. In this same context, another concept somehow inherited from the quantum formalism with a direct photonic analogue is the optical chirality; a local dynamical property that, in a way, allows one to quantifying scalarly the spin of an optical field. Apart from its controversial physical meaning and its close relationship with plasmonic systems and metamaterials, often regarded as chiral enhancers, its main feature is that, for optical fields in the vacuum, it is a conserved quantity. From a theoretical standpoint, this thesis delves into the basics of these photonic traits. Specifically, it is analytically demonstrated that the spin-orbit interaction is indeed a phenomenon that naturally and necessarily emerges at the nanoscale. Building on this, it is addressed a formalism to extend the effect of near-field unidirectional excitation beyond the dipolar approximation, thus facilitating its observation and improving the coupling performance. On the other side, the optical chirality, originally put forward for electromagnetic fields in vacuum, is thoroughly analyzed and generalized to any arbitrary medium, including highly dispersive systems. Furthermore, different configurations for implementing the main chiroptical functionalities (sensing and spectroscopy) in integrated photonic platforms are explored. Besides its potential for applications, this study lays a bridge to classically approach features and effects which are traditionally quantum-like.
This work was supported by fundings from Ministerio de Economía y Competitividad of Spain (MINECO) under Contract No.TEC2014-51902-C2-1-R. and by ERC Starting Grant No. ERC-2016-STG-714151-PSINFONI. This work was also partially supported by funding from the European Commission Project THOR H2020-EU-829067.
Vázquez Lozano, JE. (2021). Spin-Dependent Optical Phenomena: Fundamentals and Applications [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/166775
TESIS
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Laohakunakorn, Nadanai. "Electrokinetic phenomena in nanopore transport". Thesis, University of Cambridge, 2015. https://www.repository.cam.ac.uk/handle/1810/252690.
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Nanopores are apertures of nanometric dimensions in an insulating matrix. They are routinely used to sense and measure properties of single molecules such as DNA. This sensing technique relies on the process of translocation, whereby a molecule in aqueous solution moves through the pore under an applied electric field. The presence of the molecule modulates the ionic current through the pore, from which information can be obtained regarding the molecule's properties. Whereas the electrical properties of the nanopore are relatively well known, much less work has been done regarding their fluidic properties. In this thesis I investigate the effects of fluid flow within the nanopore system. In particular, the charged nature of the DNA and pore walls results in electrically-driven flows called electroosmosis. Using a setup which combines the nanopore with an optical trap to measure forces with piconewton sensitivity, we elucidate the electroosmotic coupling between multiple DNA molecules inside the confined environment of the pore. Outside the pore, these flows produce a nanofluidic jet, since the pore behaves like a small electroosmotic pump. We show that this jet is well-described by the low Reynolds number limit of the classical Landau-Squire solution of the Navier-Stokes equations. The properties of this jet vary in a complex way with changing conditions: the jet reverses direction as a function of salt concentration, and exhibits asymmetry with respect to voltage reversal. Using a combination of simulations and analytic modelling, we are able to account for all of these effects. The result of this work is a more complete understanding of the fluidic properties of the nanopore. These effects govern the translocation process, and thus have consequences for better control of single molecule sensing. Additionally, the phenomena we have uncovered could potentially be harnessed in novel microfluidic applications, whose technological implications range from lab-on-a-chip devices to personalised medicine.
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Nasta, Manish H. "Loss phenomena in perturbed single-mode optical fibers : investigation and applications /". Thesis, This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-06112009-064004/.
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Sakaida, Masaru. "Disorder-induced quantum phenomena in inhomogeneous optical lattices". 京都大学 (Kyoto University), 2016. http://hdl.handle.net/2433/215289.
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Mitchell, John Edward. "Beat noise and related phenomena in optical networks". Thesis, University College London (University of London), 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.392668.
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Selli, Raman Kumar. "Fibre optic temperature sensors using fluorescent phenomena". Thesis, City University London, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.236641.
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Schumann, Robert Paul. "Surface plasmon random scattering and related phenomena". Thesis, Connect to title online (Scholars' Bank) Connect to title online (ProQuest), 2009. http://hdl.handle.net/1794/10297.
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Typescript. Includes vita and abstract. Includes "Monte Carlo SPP Scattering Simulation Program" (leaves 107-123) Includes bibliographical references (leaves 124-129) Also available online in Scholars' Bank; and in ProQuest, free to University of Oregon users.
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Hentschel, Martina. "Mesoscopic wave phenomena in electronic and optical ring structures". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2001. http://nbn-resolving.de/urn:nbn:de:swb:14-1008319980781-38394.
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Gegenstand dieser Arbeit sind Wellenphänomene in mesoskopischen Ringstrukturen. In Teil I der Arbeit befassen wir uns mit spinabhängigem Transport von Elektronen in effektiv eindimensionalen Ringen in Gegenwart inhomogener Magnetfelder. Wir benutzen die exakten Lösungen der Schrödinger-Gleichung im allgemeinen nicht-adiabatischen Fall in einem Transfer-Matrix-Formalismus und untersuchen Auswirkungen von geometrischen Phasen auf den Magnetwiderstand. Für den Spezialfall eines Magnetfeldes in der Ringebene sagen wir einen interessanten Spin-Flip-Effekt vorher, der die Steuerung der Polarisationsrichtung von Elektronen über einen externen Aharonov-Bohm-Fluß erlaubt. Optische mesoskopische Systeme sind Thema von Teil II dieser Arbeit. Wir betrachten zweidimensionale annulare Strukturen, charakterisiert durch unterschiedliche Brechungsindizes, sowohl im klassischen Bild der geometrischen Optik als auch mit Wellenmethoden auf der Grundlage der Maxwellschen Gleichungen. Insbesondere diskutieren wir erstmals eine Streumatrixbeschreibung optischer Mikroresonatoren und wenden sie auf das dielektrische annulare Billard an. Ein Vergleich der Ergebnisse des Wellen- und Strahlenbildes liefert eine gute Übereinstimmung, jedoch sind im Grenzfall großer Wellenlängen von der Ordnung der Systemabmessungen Korrekturen zum Strahlenbild nötig. Wir zeigen am Beispiel von Fresnel-Gesetzen für gekrümmte Oberflächen erstmals, daß der Goos-Hänchen-Effekt diese Korrekturen quantitativ erfaßt. Ausgehend von der Wellenbeschreibung leiten wir neue analytische Formeln für verallgemeinerte Fresnel-Gesetze für beide möglichen Polarisationsrichtungen ab. Die Anwendung des Strahlenbildes erlaubt eine schlüssige Interpretation eines Experiments mit einer quadrupolaren Glasfaser, außerdem schlagen wir Strahlenkonzepte als Grundlage der Konstruktion von Mikrolasern mit maßgeschneiderten Charakteristika vorIn this work we investigate wave phenomena in mesoscopic systems using different theoretical approaches. In Part I, we focus on effectively one-dimensional electronic ring structures and address the phenomenon of geometric phases in spin-dependent electronic transport in the presence of non-uniform magnetic fields. In the general non-adiabatic case, exact solutions of the Schrödinger equation are used in a transfer matrix formalism to compute the transmission probability through the ring. In the magneto-conductance we identify clear signatures of interference effects due to geometric phases, for example in rings where the non-uniform field is created by a central micromagnet. For the special case of an in-plane magnetic field we predict an interesting spin-flip effect that allows one to control the spin polarization of electrons by applying an external Aharonov-Bohm flux. Optical mesoscopic systems are the subject of Part II. We consider two-dimensional annular structures characterized by different refractive indices, and apply classical methods from geometric optics as well as wave concepts based on Maxwell's equations. For the first time, an S-matrix approach is successfully employed in the description of resonances in optical microresonators; in particular we propose the dielectric annular billiard as an attractive model system. Comparing ray and wave pictures, we find general agreement, except for large wavelengths of the order of the system size, where corrections to the ray model are necessary. The Goos-Hänchen effect as an extension of the ray picture is shown to quantitatively account for wave modifications of Fresnel's laws due to curved interfaces. We derive novel analytical expressions for the corrected Fresnel formulas for both polarizations of light. Motivated by the successful ray description, we give a conclusive interpretation of a recent filter experiment on a quadrupolar glass fibre, and suggest novel concepts for microresonator-based lasers
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Enell, Carl-Fredrik. "Optical studies of polar stratospheric clouds and related phenomena /". Kiruna : Swedish Institute of Space Physics (Institutet för rymdfysik), 2002. http://www.irf.se/publications/SciReports/IRFreport278.pdf.
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Hill, Matthew Peter. "A test of special relativity using coherent optical phenomena". Thesis, University of Leeds, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.522943.
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Cotter, Joseph paul. "A precision test of relativity using coherent optical phenomena". Thesis, University of Leeds, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.487714.
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The Lorentz symmetries lie at the heart of all modem physics. However, recent theoretical investigations into physics ics beyond the standard model have proposed a violation to these symmetries. One manifestation of Lorentz violation consistent with current observational evidence and therefore permitted by these theories is a small frame dependancy in the speed of Ught. Such a violation is investigated here.
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Fischbach, Stefan. "Nonlinear optical phenomena in fluoride glass and hybrid fibres". Thesis, University of Bath, 2017. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.715304.
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This thesis investigates nonlinear optical phenomena in non-silica fibres, in a first part utilising a fluoride fibre, followed by the exploration of hybrid fibres with an organic single crystal inside a fibre capillary. The unique properties of 55ZrF4, 18BaF2, 6LaF3, 4AlF3, 17NaF (ZBLAN) glass allow the creation of optical fibres with a highly extended transmission window on the longer wavelength side. We investigated the properties of ZBLAN fibres in order to optimise supercontinuum (SC) generation in a ZBLAN fibre pumped by an optic parametric amplifier. To study applications of the ZBLAN SC we integrated the SC into a pump-probe setup, being used as a near-infrared broadband probe source. We have carried out proof-of-principle measurements on an organic copolymer thin-film, showing the possibility of utilising a ZBLAN SC, allowing to extend the usability of broadband sources to the nearand mid-infrared, while simplifying the usage of the setup. The second part of this thesis explores the possibilities of hybrid fibres by using a hollow-core silica capillary with an organic single-crystal inside. We have developed and optimised a method to grow an organic semiconducting crystal inside a hollow core capillary based on the Bridgman-technique. We could demonstrate the filling of the inner capillary for diameters down to 1 m and with different materials based on the anthracene structure, opening up possibilities for various hybrid fibres. The quality of the single-crystals was evaluated by micro-Raman and X-ray diffraction measurements. We could access nonlinear properties of the crystal by coupling light with an energy lower than the band-gap into the fibre. Stimulated by two-photon absorption photo-luminescence from the fibre core was observed for the hybrid fibre. The results obtained for the hybrid fibres gives rise to a vast amount of possibilities for different hybrid fibres with tailored optical properties of organic materials and their optimisation in the guiding of light.
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Hadis, Mohammed Abdul. "Polymerisation kinetics and optical phenomena of photoactive dental resins". Thesis, University of Birmingham, 2011. http://etheses.bham.ac.uk//id/eprint/1730/.
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Globally, several shortcomings of dental resin based composites (RBCs) remain. This may be related to problems associated with incomplete conversion (40-70%), polymerisation shrinkage (1-4% by volume) and the stress generated at the tooth/restoration interface. Additionally, the increased number of technique sensitive incremental steps required to fill relatively large cavities is due to inefficient light transmission at depths greater than 2mm. The current investigation demonstrates the applicability of the exposure reciprocity law in photoactive dental materials in order to try and improve these shortcomings. The development techniques that will allow dynamic monitoring of optical and physical change will aid material development with the goal of improving cure depths. The current investigation has demonstrated the use of several analytical techniques (FT-IR spectroscopy, UV-Vis Spectroscopy and low coherence interferometry) and shown the complexity of optical phenomena within RBCs, which are affected by material composition as well as cavity dimensions. Whilst research continues to develop a novel RBC with reduced shrinkage and improved depths of cure, there is currently no commercially available solution to such problems. Consequently a better understanding of the setting reaction, optical properties and physical properties will aid material development.
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Uno, Kazuyuki. "Localization Phenomena and Optical Properties in AlGaAs Disordered superlattices". Kyoto University, 1997. http://hdl.handle.net/2433/202282.
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Mai, Thuc T. "Optical spectroscopy of cooperative phenomena and their symmetries in solids". The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1555629359625425.
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Huynh, Dan-Nha. "Nonlinear optical phenomena within the discontinuous Galerkin time-domain method". Doctoral thesis, Humboldt-Universität zu Berlin, 2018. http://dx.doi.org/10.18452/19396.
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Diese Arbeit befasst sich mit der theoretischen Beschreibung nichtlinearer optischer Phänomene in Hinblick auf das (numerische) unstetige Galerkin-Zeitraumverfahren. Insbesondere werden zwei Materialmodelle behandelt: das hydrodynamische Modell für Metalle und das Modell für Raman-aktive Materialien. Im ersten Teil der Arbeit wird das hydordynamische Modell für Metalle unter Verwendung eines störungstheoretischen Ansatzes behandelt. Insbesondere wird dieser Ansatz genutzt, um die nichtlinearen optischen Effekte, Erzeugung zweiter Harmonischer und Summenfrequenzerzeugung, mit Hilfe des unstetigen Galerkin-Verfahrens zu studieren. In diesem Zusammenhang wird demonstriert, wie das optische Signal zweiter Ordnung von Nanoantennen optimiert werden kann. Hierzu wird ein hier erarbeitetes Schema für die Abstimmung des eingestrahten Lichtes angewandt. Zudem führt eine intelligente Wahl des Antennendesigns zu einem optimierten Signal. Im zweiten Teil dieser Arbeit wird das Modell für Raman-aktive Dielektrika behandelt. Genauer wird die nichtlineare Antwort dritter Ordnung für stimulierte Raman-Streuung hergeleitet. Diese wird dazu genutzt, um ein System aus Hilfsdifferentialgleichungen für das unstetige Galerkin-Verfahren zu konstruieren. Die Ergebnisse des erweiterten numerischen Verfahrens werden im Anschluss gezeigt und diskutiert.This thesis is concerned with the theoretical description of nonlinear optical phenomena with regards to the (numerical) discontinuous Galerkin time-domain (DGTD) method. It deals with two different material models: the hydrodynamic model for metals and the model for Raman-active dielectrics. In the first part, we review the hydrodynamic model for metals, where we apply a perturbative approach to the model. We use this approach to calculate the second-order nonlinear optical effects of second-harmonic generation and sum-frequency generation using the DGTD method. In this context, we will see how to optimize the second-order response of plasmonic nanoantennas by applying a deliberate tuning scheme for the optical excitations as well as by choosing an intelligent nanoantenna design. In the second part, we examine the material model for Raman-active dielectrics. In particular, we see how to derive the third-order nonlinear response by which one can describe the process of stimulated Raman scattering. We show how to incorporate this third-order response into the DGTD scheme yielding a novel set of auxiliary differential equations. Finally, we demonstrate the workings of the modified numerical scheme.
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Yin, Xiaobo. "Optical nonspecular phenomena at the surface plasmon resonance and their applications /". May be available electronically:, 2008. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
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Moraes, Eduardo Carlo Mascarenhas. "Collective and optical phenomena in equilibrium and nonequilibrium interacting quantum systems". Universidade Federal de Minas Gerais, 2014. http://hdl.handle.net/1843/BUOS-9TPHLT.
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In this thesis we study collective, emergent and optical properties of interacting quantum systems both in equilibrium and nonequilibrium situations from a microscopic modelling. This orientation steams from both the fact there is a profound need to design, characterise and set up control strategies for realistic systems in which quantum technologies could be conceived and the interest to grasp and identify fundamental principles for the emergence of macroscopic behaviour. The thesis is divided into three parts: I Optical and Collective Phenomena; II Equilibrium many-body systems and III Nonequilibrium many-body systems. Part I includes four complementary contributions to the optics emerging from the collective behaviour of microscopic quantum systems. In part II (Equilibrium many-body systems) of the thesis I have addressed the physics of quantum phase transitions from the perspective of nonequilibrium thermodynamics. We have shown that such an approach captures the essential features of finite order transitions that have a strong connection to thermodynamical and energetic figures of merit, but does not capture infinite order transitions that are of a much more subtle nature. Motivated by these exotic infinite order transitions we have looked at quantum phases and phase transitions through an informational and operational perspective based on pure state conversions restricted by local operations. In the third and last part (Nonequilibrium many-body systems) of the thesis I have laid out a project on the closed evolution of quantum spin chains focussing on the emergent nonequilibrium laws that depart from equilibrium physics.
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Sundaresan, Vignesh. "OPTICAL IMAGING AND MECHANISTIC STUDIES OF ELECTROCHEMICAL PHENOMENA AT THE NANOSCALE". Diss., Temple University Libraries, 2018. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/585694.
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ChemistryPh.D.
In this work, we use optical methods to study electrochemical reactions and processes occurring on the nanometer length scale. Optical methods are advantageous over traditional electrochemical methods because of their high spatial resolution and sensitivity at both the single nanoparticle and single molecule level. This dissertation describes a series of studies in which super-localization and dark-field optical imaging is used to provide insight into spatial and temporal heterogeneity in nanoscale electrochemical systems with <25 nm spatial resolution. In the first set of experiments, three-dimensional (3-D) super-resolution imaging is used to determine the tip-substrate distance in nanoscale scanning electrochemical microscopy (SECM) with precision better than 25 nm. Correlating the tip-substrate distance using both optical and electrochemical techniques showed excellent agreement. Second, single nanoparticles (NP) were delivered through a nanopipette, and their resistive-pulse signals were correlated with a fluorescence optical signal. The diffusion trajectories of individual NP delivered to the external solution and to an electrified interface were obtained by 3-D super-resolution imaging, and showed signatures of both sub-diffusive and super-diffusive behavior, depending on the balance of forces between the flow from the pipette and the applied potential at the electrified substrate. Next, we studied the influence of surface oxide layers on single silver NP electrodissolution by tracking the intensity and spatial variation of scattering from single nanoparticles over time. We discovered that silver NPs can undergo electrodissolution in either a spatially symmetric or asymmetric manner, based on the nature of the surface oxide layer. Moreover, we also reported the simultaneous electrodeposition of silver oxide at the electrode surface during the electrodissolution of silver NPs, which enabled us to study the effect of multiple simultaneous redox reactions and their effects on one another. Overall, these experiments reveal local heterogeneity in nanoscale electrochemical processes and allow for many single nanoparticles to be measured in parallel, revealing relationships that are hidden using traditional electrochemical measurements.
Temple University--Theses
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Närger, Ulrike. "Optical study of the critical behaviour of pure fluids and binary mixtures". Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/30786.
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Optical techniques were used to study the critical behaviour of the pure fluids CHF₃, CCIF₃ and Xe, and binary mixtures He-Xe and nicotine + water. We find that for all these substances, the order parameter is described by a power law in the reduced temperature t = (Tc - T)/Tc with a leading exponent β = 0.327 ± 0.002. Also, we determine the first correction to scaling exponent to be Δ = 0.43 ± 0.02 for the pure fluids and Δ = 0.50 ± 0.02 for the He-Xe system.
The coexistence curve diameter in CHF₃ and CCIF₃ exhibits a deviation from rectilinear
diameter, in agreement with a modern theory which interprets this behaviour as resulting from three-body effects. In contrast, no such deviation is observed in Xe where, according to that theory, it should be more pronounced than in other substances.
In the polar fluid CHF₃, the order parameter, isothermal compressibility and the chemical potential along the critical isotherm were simultaneously measured in the same experiment in an effort to ensure self-consistency of the results. From the data, two amplitude ratios which are predicted to be universal are determined: Γ+⃘ /Γ-⃘= 4.8 ± 0.6 and D⃘Γ+⃘B⃘δ-₁ = 1.66 ± 0.14.
In the binary liquid system nicotine + water, the diffusivity was measured both by light scattering and by interferometry. The results agree qualitatively, but differ by a factor of ≈ 2. From the light scattering data, the critical exponent of the viscosity is found to be zη = 0.044 ± 0.008.
The interferometric experiments on Xe and He-Xe furnish a direct way to maesure the effects of wetting: From the data, the exponent of the surface tension is found to be n = 1.24 ± 0.06. The similarity of the order parameter and compressibility in Xe and a He-Xe mixture containing 5% He indicate that the phase transition in this He-Xe mixture is of the liquid-gas type rather than the binary liquid type.Science, Faculty of
Physics and Astronomy, Department of
Graduate
26
Vanin, Evgeny V. "Nonlinear pulse propagation and staturation gain grating phenomena in optical fiber devices /". Stockholm, 1999. http://www.lib.kth.se/abs99/vani0318.pdf.
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Papageorgiou, Georgios. "Ultrafast nonlinear optical phenomena in wide-bandgap II-VI semiconductor quantum wells". Thesis, Heriot-Watt University, 2004. http://hdl.handle.net/10399/2026.
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Abbas, Bassam. "Linear and nonlinear optical phenomena in thin sol-gel organic-inorganic films". Thesis, University of Reading, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.298744.
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Zwiggelaar, Reyer. "Coherence and polarisation phenomena in optical systems and fibres for signal processing". Thesis, University College London (University of London), 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319932.
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Thacker, Vivek Vijay. "Optical studies of DNA nanostructures, electrokinetic phenomena and molecular transport in nanocapillaries". Thesis, University of Cambridge, 2014. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708285.
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Reed, Evan J. (Evan John) 1976. "Optical, electronic, and dynamical phenomena in the shock compression of condensed matter". Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/16935.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2003.Includes bibliographical references (leaves 109-113).
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Despite the study of shock wave compression of condensed matter for over 100 years, scant progress has been made in understanding the microscopic details. This thesis explores microscopic phenomena in shock compression of condensed matter including electronic excitations at the shock front, a new dynamical formulation of shock waves that links the microscopic scale to the macroscopic scale, and basic questions regarding the role of crystallinity in the propagation of electromagnetic radiation in a shocked material. In Chapter 2, the nature of electronic excitations in crystalline solid nitromethane are examined under conditions of shock compression. Density functional theory calculations are used to determine the crystal bandgap under hydrostatic stress, uniaxial strain, and shear strain for pure and defective materials. In all cases, the bandgap is not lowered enough to produce a significant population of excited states. In Chapter 3, a new multi-scale simulation method is formulated for the study of shocked materials. The method allows the molecular dynamics simulation of the system under dynamical shock conditions for orders of magnitude longer time periods than is possible using the popular non-equilibrium molecular dynamics (NEMD) approach. An example calculation is given for a model potential for silicon in which a computational speedup of 10⁵ is demonstrated. Results of these simulations are consistent with some recent experimental observations. Chapters 4 and 5 present unexpected new physical phenomena that result when light interacts with a shock wave propagating through a photonic crystal.
(cont.) These new phenomena include the capture of light at the shock wave front and re-emission at a tunable pulse rate and carrier frequency across the bandgap, and bandwidth narrowing of an arbitrary signal as opposed to the ubiquitous bandwidth broadening. Reversed and anomalous Doppler shifts are also predicted in light reflected from the shock front.
by Evan J. Reed.
Ph.D.
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Thota, Venkata Ramana Kumar. "Tunable Optical Phenomena and Carrier Recombination Dynamics in III-V Semiconductor Nanostructures". Ohio University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1451807323.
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Porritt, Dawn, i n/a. "The magnificent play of light: seeing the difference". University of Canberra. Design and Architecture, 2007. http://erl.canberra.edu.au./public/adt-AUC20081023.115855.
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Light as a concept is filled with a multitude of interpretations, ideas and possibilities and
no matter how technologically progressive we think we are, nature consistently controls
our human way of life. We are surrounded by nature and often gain inspiration by the
simple things around us. My interest in the phenomena of light and refraction was
sparked years ago by Claude Monet?s painting Bathers at La Grenouillere, 1869. It
showed simplicity of form and shape, yet emitted a luminosity and radiance of light
reflecting off water.
This thesis examines the subject of light as an optical phenomenon. My specific aim was
to create distorted, ambiguous and conflicting images in my photographs by using the
"optical phenomena" of light such as, refraction, diffraction and reflection as a basis for
abstracting reality. I wanted to capture the changes that occur when light changes
direction due to refractive qualities within a material such as glass, water or plastic, or
due to the reflective qualities of a surface.
The camera was exploited for its capacity to capture realism, but also to capture and
abstract natural phenomenon. The images were enlarged to magnify details and the
reality of the physical world was heightened as objects became ambiguous. Design
compositional techniques were used to decontextualise objects.
I approached this study with the idea that observation and awareness has importance to
image making within my design and teaching practice. This thesis presents my project
explorations showing the play of light on and through surfaces under different conditions.
I have documented this by producing a series of photographic images and a glossary as
an aid in the practice of design education.
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Яковенко, А. А. "Оптичні явища в природі та їх наукове пояснення". Thesis, Сумський державний університет, 2013. http://essuir.sumdu.edu.ua/handle/123456789/40888.
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Kalli, Kyriacos. "Investigation of linear and non-linear optical phenomena using high finesse ring resonators". Thesis, University of Kent, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314457.
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Dimopoulos, C. "Study of dynamic phenomena in WDM optical fibre links and networks based on EDFAs". Thesis, University of Essex, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327071.
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Nagao, Kazuma. "Fluctuations and non-equilibrium phenomena in strongly-correlated ultracold atoms". Kyoto University, 2019. http://hdl.handle.net/2433/242588.
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Finke, Justin David. "Monte Carlo/Fokker-Planck simulations of Accretion Phenomena and Optical Spectra of BL Lacertae Objects". Ohio University / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1181833339.
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Reid, Benjamin A. "An optical investigation of cavitation phenomena in true-scale high-pressure diesel fuel injector nozzles". Thesis, Loughborough University, 2010. https://dspace.lboro.ac.uk/2134/6358.
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Efforts to improve diesel fuel sprays have led to a significant increase in fuel injection pressures and a reduction in nozzle-hole diameters. Under these conditions, the likelihood for the internal nozzle flow to cavitate is increased, which potentially affects spray breakup and atomisation, but also increases the risk of causing cavitation damage to the injector. This thesis describes the study of cavitating flow phenomena in various single and multi-hole optical nozzle geometries. It includes the design and development of a high-pressure optical fuel injector test facility with which the cavitating flows were observed. Experiments were undertaken using real-scale optical diesel injector nozzles at fuel injection pressures up to 2050 bar, observing for the first time the characteristics of the internal nozzle-flow under realistic fuel injection conditions. High-speed video and high resolution photography, using laser illumination sources, were used to capture the cavitating flow in the nozzle-holes and sac volume of the optical nozzles, which contained holes ranging in size from 110 micrometers to 300 micrometers. Geometric cavitation in the nozzle-holes and string cavitation formation in the nozzle-holes and sac volume were both observed using transient and steady-state injection conditions; injecting into gaseous and liquid back pressures up to 150 bar. Results obtained have shown that cavitation strings observed at realistic fuel injection pressures exhibit the same physical characteristics as those observed at lower pressures. The formation of string cavitation was observed in the 300 micrometers multi-hole nozzle geometries, exhibiting a mutual dependence on nozzle flow-rate and the geometry of the nozzle-holes. Pressure changes, caused by localised turbulent perturbations in the sac volume and transient fuel injection characteristics, independently affected the geometric and string cavitation formation in each of the holes. String cavitation formation of was shown to occur when free-stream vapour was entrained into the low pressure core of a sufficiently intense coherent vortex. Hole diameters less than or equal to 160 micrometers were found to suppress string cavitation formation, with this effect a result of the reduced nozzle flow rate and vortex intensity. Using different hole spacing geometries, it was demonstrated that the formation of cavitation strings in a particular geometry became independent of fuel injection and back pressure once a threshold pressure drop across the nozzle had been reached.
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Lai, Yu Hang. "Strong Field Phenomena in Atoms and Molecules from Near to MidInfrared Laser Fields". The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1514852456303011.
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Karunanayaka, Prasanna Rasika. "A Dispersion Formula for Analyzing Modal Interference Among Guided and Free Electromagnetic Wave Modes and Other Phenomena in a Circular Optical Fiber". University of Cincinnati / OhioLINK, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1100844976.
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Janík, Lukáš. "Podpůrný systém pro správu a řízení FSO transceiveru". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2016. http://www.nusl.cz/ntk/nusl-241040.
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Tato práce se zabývá problematikou optických bezkabelových spojů (FSO). V úvodní kapitole jsou diskutovány přednosti, základní principy a dílčí komponenty FSO spojů. Druhá kapitola se zabývá atmosférou z pohledu šířícího se optického svazku, jejím složením, základními veličinami a jevy v ní nastávajícími. V následující kapitole je popsáno několik metod ke zmírnění jevů majících negativní vliv na kvalitu spoje. Druhá část práce se zabývá návrhem podpůrného systému pro FSO, založeném na softcore mikroprocesoru MicroBlaze, návrhem jednoduchého síťového přepínače a síťového rozhraní. Závěr práce pojednává o implementaci webového serveru a tvorbě webové prezentace umožňující vzdálenou správu FSO a jeho komponent.
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Qin, Yu. "Versatility of nonlinear optical phenomena induced by infrared pulses: application to pulse characterization, element analysis, and filamentation". Kyoto University, 2015. http://hdl.handle.net/2433/200464.
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Peil, Michael. "Dynamics and synchronization phenomena of semiconductor lasers with delayed optical feedback utilizing nonlinear dynamics for novel applications". Berlin Logos-Verl, 2006. http://deposit.ddb.de/cgi-bin/dokserv?id=2793060&prov=M&dok_var=1&dok_ext=htm.
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Dhanjal, Sukhminder J. "Observations of transient nonlinear optical effects on reflection from opaque media and novel polarisation phenomena in crystals". Thesis, University of Southampton, 1999. https://eprints.soton.ac.uk/351450/.
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The degenerate cubic optical nonlinearity of an indium-glass interface in the vicinity of the melting point has been measured for the first time at 1260 nm using a spectroscopic technique based on the pump probe specular inverse Faraday effect. A considerable enhancement of the nonlinearity was observed approaching the melting point from below with a magnitude of 6.3 x 10−7 e.s.u. (8.8 x 10−15 m2Volt−2) The nonlinear response was faster than 90 fs. Away from the melting the nonlinearity is attributed to the spin flipping mechanism. Near the melting point it is associated with weakly bound highly unharmonic electrons. An optical nonlinearity of a gallium dielectric interface has been used to achieve a broadband light by light control at milliwatt power levels. The broadband optical nonlinearity of an α-gallium-dielectric interface is shown to enhance near the bulk melting point (30°). The magnitude of the nonlinearity is ~1 e.s.u. (1.4x10−8 m2Volt−2). The nonlinear response was found to have various components ranging from at least in the micro to nanosecond range. Up to a 30% modulation of a probe beam in reflected light intensity has been observed. In a fiberised architecture the nonlinearity is exploited to make an optical switch at 1.5 µm. Cross wavelength switching is also presented at 1.3 µm and 1.5 µm where the modulation in reflected light exceeded 40% with dynamics of ~140ns. Based on the same nonlinearity a new passive self-starting Q-switching ring laser is presented. The pulse duration is ~1.5 µs with peak powers exceeding >100mW. The nonlinearity is attributed to the metallisation and recrystallisation velocities of gallium. The nonreciprocity of natural polarisation has been observed in the optically active crystal Bi12SiO20 at 632.8, 514.5, 501.7, 496.5, 476.5, and 457.9 nm. A nonreciprocal component of the polarisation rotation of radians was detected on the background of the polarisation rotation due to conventional optical activity. The nonreciprocal rotation has been attributed to the presence of the symmetric part of the nonlocality tensor Re[γxyz + γxyz] ~ 5 x 10−12 cm at 457.9 nm. The giant birefringence (0.03 < dn < 0.3) due to the quadratic term in the constitutive equation for ZnSe along the [110] direction in the excitonic region in reflection was measured for the first time. Using this effect a reflective configuration technique for studying crystallographic domains in cubic crystals has been developed.
46
Mondanos, Michael. "Characterisation and investigation of polarisation phenomena for application in all-in-line optical fibre sensing and communication systems". Thesis, Imperial College London, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.419795.
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Pohl, Martin [Verfasser], Ilya [Akademischer Betreuer] Akimov i Heinz [Gutachter] Hövel. "Ultrafast optical phenomena in magneto-plasmonic crystals and magnetically ordered materials / Martin Pohl. Betreuer: Ilya Akimov. Gutachter: Heinz Hövel". Dortmund : Universitätsbibliothek Dortmund, 2014. http://d-nb.info/1105476111/34.
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Rocha, Rafael Santos. "Influência do observador, do iluminante e do ângulo de visualização na perceptibilidade e aceitabilidade de diferenças de brilho superficial de resinas compostas". Universidade Estadual Paulista (UNESP), 2017. http://hdl.handle.net/11449/152401.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
O objetivo deste trabalho foi avaliar a influência de observadores sobre a percepção e aceitabilidade de brilho superficial de resinas compostas, sob diferentes iluminantes, em angulação livre e pré-determina em 60°. E ainda, determinar o limite de perceptibilidade e aceitabilidade da variação de unidade de brilho (∆UB) entre os espécimes. Foram confeccionados 8 espécimes cilíndricos de 6 mm de diâmetro e 1,5 mm de espessura de resina composta, bem como um espécime padrão de dente humano, com 0,5 mm de espessura em esmalte e 1 mm em dentina. Os espécimes receberam polimento a fim de que se obtivesse ao final do processo amostras com 10 UB, 20 UB, 30 UB, 40 UB, 50 UB, 60 UB, 70 UB e 80 UB e um padrão de dente humano de 80 UB. Foram selecionados 60 observadores (20 leigos, 20 alunos de graduação e 20 cirurgiões-dentistas). O estudo foi submetido e aprovado pelo comitê de ética local. Os participantes fizeram a qualificação do brilho superficial de resina composta em cabine de luz (Gti – Newburgh,NJ). Para tanto, as amostras foram posicionadas no interior da cabine, duas a duas de forma aleatória, de forma com que a luz incidisse sua superfície em um ângulo de 60°. Os observadores responderam perguntas específicas para se determinar o nível e limite de perceptibilidade das variações de brilho. Todas as análises foram realizadas em duas condições de iluminação, com iluminantes D65 e luz fluorescente. Cinquenta por cento dos observadores iniciaram as análises com ângulo de visualização livre, seguido da qualificação em angulação pré-definida em 60° e, os demais observadores fizeram as observações de forma oposta. Para o nível e limite de aceitabilidade da variação do brilho, as amostras foram individualmente comparadas com o padrão de dente humano. Os dados foram analisados pelo teste Modelo Generalizado Linear/Não-Linear PROBIT e regressão não-linear PROBIT (5%). Para a perceptibilidade, foram encontradas diferenças significantes para a variação de brilho (Δ UB) (p<0,001), para os observadores (p=0,043) e para os iluminantes (p<0,001), no entanto, não houve diferença entre o ângulo de visualização livre e fixo em 60° (p=0,303). Em relação à aceitabilidade, foram observadas diferenças significantes para a variação de brilho (Δ UB) (p<0,001), para os observadores (p=0,003), para os iluminantes (p=0,045) e no ângulo de visualização livre e fixo em 60° (p<0,001). Os limites de perceptibilidade e aceitabilidade, levando em consideração todos os fatores foi de 6,4 UB e 35,7 UB, respectivamente. Conclui-se que fatores rotineiramente encontrados em situações clínicas influenciam a perceptibilidade e aceitabilidade de diferenças de brilho superficial de resinas compostas e que apesar de perceberem limites menores de diferença de brilho, os observadores aceitam clinicamente diferenças cinco vezes maiores.
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Panzer, Fabian [Verfasser], i Anna [Akademischer Betreuer] Köhler. "Understanding the impact of order-disorder phenomena on the optical properties of photoactive semiconducting materials / Fabian Panzer ; Betreuer: Anna Köhler". Bayreuth : Universität Bayreuth, 2016. http://d-nb.info/1115250280/34.
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Huynh, Dan-Nha [Verfasser], Kurt [Gutachter] Busch, Alejandro [Gutachter] Saenz i Stephen K. [Gutachter] Gray. "Nonlinear optical phenomena within the discontinuous Galerkin time-domain method / Dan-Nha Huynh ; Gutachter: Kurt Busch, Alejandro Saenz, Stephen K. Gray". Berlin : Humboldt-Universität zu Berlin, 2018. http://d-nb.info/1185577904/34.
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