In this Ph.D. thesis, we construct and study a number of new type IIB supergravity backgrounds that realize various flavored, finite temperature, and non-supersymmetric deformations of the resolved and deformed conifold geometries. We make heavy use of a U-duality solution generating procedure that allows us to begin with a modification of a family of solutions describing the backreaction of D5 branes wrapped on the S^2 of the resolved conifold, and generate new backgrounds related to the Klebanov-Strassler background. We first construct finite temperature backgrounds which describe a configuration of N_c D5 branes wrapped on the S^2 of the resolved conifold, in the presence of N_f flavor brane sources and their backreaction i.e. N_f/N_c ~ 1. In these solutions the dilaton does not blow up at infinity but stabilizes to a finite value. The U-duality procedure is then applied to these solutions to generate new ones with D5 and D3 charge. The resulting backgrounds are a non-extremal deformation of the resolved deformed conifold with D3 and D5 sources. It is tempting to interpret these solutions as gravity duals of finite temperature field theories exhibiting phenomena such as Seiberg dualities, Higgsing and confinement. However, a first necessary step in this direction is to investigate their stability. We study the specific heat of these new flavored backgrounds and find that they are thermodynamically unstable. Our results on the stability also apply to other non-extremal backgrounds with Klebanov-Strassler asymptotics found in the literature. In the second half of this thesis, we apply the U-duality procedure to generate another class of solutions which are zero temperature, non-supersymmetric deformations of the baryonic branch of Klebanov-Strassler. We interpret these in the dual field theory by the addition of a small gaugino mass. Using a combination of numerical and analytical methods, we construct the backgrounds explicitly, and calculate various observables of the field theory. / text

This thesis establishes a precise mathematical connection between the Einstein equations of general relativity and the incompressible Navier-Stokes equation of fluid dynamics. We carry out a holographic analysis which relates solutions to the Einstein equations to the behaviour of a dual fluid living in one fewer dimensions. Gravitational systems are found to exhibit Navier-Stokes behaviour when we study the dynamics of the region near an event horizon. Thus, we find non-linear deformations of Einstein solutions which, after taking a suitable near horizon limit and imposing our particular choice of boundary conditions, turn out to be precisely characterised by solutions to the incompressible Navier-Stokes equation. In other words, for any solution to the Navier-Stokes equation, the set-up we present provides a solution to the Einstein equations near a horizon. We consider the cases of fluids flowing on the plane and on the sphere. Fluid dynamics on the plane is analysed foremost in the context of a flat background geometry whilst the spherical analysis is undertaken for Schwarzschild black holes and the static patch of four-dimensional de Sitter space. / Physics

published_or_final_version / Physics / Master / Master of Philosophy

This work presents the recent advances in photorefractive polymers for use in updatable holographic displays. A model with which to predict the effect of coplanar electrode geometry on diffraction uniformity in photorefractive (PR) polymer display devices was developed. Assumptions made in the standard use cases with constant electric field throughout the bulk of the media are no longer valid in the regions of extreme electric fields present in this type of device. Using electric field induced second harmonic generation (EFISHG) observed with multiphoton microscopy, the physical response in regions of internal electric fields which fall outside the standard regimes of validity were probed. Adjustments to the standard model were made, and the results of the new model were corroborated by holographic four-wave mixing measurements. The recent development of a single mode fiber-based pulsed laser with variable pulse length, energy, and repetition rate has enabled the characterization of photorefractive devices in a previously inaccessible regime located between millisecond and nanosecond pulse recording. A pulse width range of nine orders of magnitude opens the door to device and supporting laser optimization for use in video-rate holographic display. Device optimization has resulted in 5x improvement in single pulse four-wave mixing diffraction efficiencies to 10 - 11.5 % at pulse widths ranging between 6 ns and 100 µs. The grating recording time was likewise reduced by 5x to 16 ms at an applied bias of 72.5 V/μm. These improvements support 30 Hz update rates, which combined with the 3.3 - 10 kHz repetition rate pulsed laser, pave the way for real-time updatable holographic display.

Here it is demonstrated that nanofabricated structures can be used as electron optical elements in new types of electron interferometers. This enables novel investigations with electrons analogous to experiments in light and atom optics. Far field diffraction from a single nanograting is used to examine the force on a charge moving in close proximity to a surface. Near field diffraction from the nanograting is investigated in a Talbot interferometer. It is found that electron waves form replicas of the grating in free space, and these replicas can be de-magnified using illumination by a converging beam. An electron Lau interferometer has the same grating configuration as the Talbot interferometer, but uses spatially incoherent beams that give rise to drastically different interference behavior. A single optical theory is developed to efficiently model a variety of grating interferometers under a diverse set of illumination conditions, and it is used to understand the experiments described here. Applications for these new interferometers are discussed, as well as possible directions for future research.

No description available.

The main purpose of the project was to create an initial lab set-up for a dig-ital in-line holographic microscope and a reconstruction algorithm. Different parameters including: light source, pin-hole size and distances pinhole-object and object-camera had to be optimized. The lab set-up is to be developed further by a master student at the University of Nairobi and then be used for malaria detection in blood samples. To acquire good enough resolution for malaria detection it has been found necessary to purchase a gray scale camera with smaller pixel size. Two dierent approaches, in this report called the on-sensor approach and the object-magnication approach, were investigated. A reconstruction algorithm anda phase recovery algorithm was implemented as well as a super resolution algorithm to improve resolution of the holograms. The on-sensor approach proved easier and cheaper to use with approximately the same results as the object-magnication method. Necessary further research and development of experimental set-up was thoroughly discussed. / Projketet har gått ut på att bygga en billigare och enklare metod för att identifiera malaria i blodprover. Malaria är ett stort problem i en mängd områden i världen. Flera av dessa är fattiga och kan i nuläget inte tillhandahålla den här tjänsten till sin befolkning. Förutom att dyr apparatur krävs måste även utbildad personal lägga ner mycket tid för att kolla en stor mängd blodprover för att statistiskt säkerställa om en person har malaria eller inte. Vårt mål var att bygga en labbuppställning för "Digital in line holographic microscopy" och en rekonstruktionsalgoritm som en masterstudent vid Nairobi universitet ska fortsätta utveckla. Vi kom också fram till vilken upplösning som krävdes för att kunna urskilja malaria i blodproverna. Digital in line holographic microscopy går till så att man har en ljuskälla som riktas genom ett pinnhål, ljuset som går genom pinnhålet ljuser upp det prov, blodproverna i vårt fall, man vill undersöka och det resulterande ljuset fångas på en kamera. Med kunskap om fourieroptik går det att rekonstruera den digitala bilden man fångat på kameran, innan rekonstruktion är den ett hologram vilken är svårtydd. Labbuppställningen byggdes delvis med en 3D printer. För att förbättra resultaten implementerades flera algoritmer vilka lade ihop en mängd förskjutna bilder till en bättre bild, så kallad super resolution. Vi lyckades inte komma till den upplösning som krävdes för att urskilja malaria men gjorde en grundlig förstudie och en utförlig beskrivning av det arbete som väntar den student som fortsätter med projektet. Framför allt beskrevs värden på parametrar och vilken typ av kamera som ska användas för att optimera uppställningen.

The Confocal Scanning Laser Holography (CSLH) microscope non-intrusively measures the three-dimensional (3D) temperature and composition of a solid, fluid, or plasma. A unique reconstruction algorithm uses phase-shift data from the recorded holograms and boundary conditions of the specimen to measure the 3D temperature. The CSLH microscope uniquely combines holography with a scanning confocal microscope to determine the phase-shift in a hologram and to reconstruct the 3D temperature. The confocal aspect of the microscope reduces optical aberrations in the hologram and increases sensitivity to a temperature at a scan position in the specimen. The optical design maintains a stationary focal point on the pinhole aperture within the confocal optics during scanning. The CSLH microscope uses a focused laser beam instead of a collimated beam to probe the specimen. The advantage of the focused probe beam over the collimated beam is that different phase-shift data is obtained for each scan position of the probe beam. Another advantage is preventing rotational scanning of the laser about the specimen or rotating the specimen, increasing the number of practical applications. This limits the scan angle to the cone angle of the probe beam only. Reconstruction of the 3D temperature given restricted scanning from a single viewing window places a burden on the reconstruction algorithm to produce low reconstruction error. Three-dimensional reconstruction using methods of tomography prove inaccurate due to the small cone angle. The result is ill-conditioned reconstruction matrices. A unique low reconstruction error algorithm given a single viewpoint window that specifies a particular scanning geometry and requires boundary conditions is derived for the microscope. This research involved the design, building, and evaluation of a specific CSLH microscope intended for fluid flow and heat transfer studies in micro-gravity space based experiments. The fluid specimen used to evaluate the microscope sets a benchmark for resolution, sensitivity, and performance. The reconstruction error is primarily due to measurement error, residual optical aberrations affecting holograms, and vibrations since the reconstruction algorithm error is negligible. Additional knowledge gained includes the understanding of sensitivity to optical alignment as well as methods to accurately determine the phase-shift in a varying fringe contrast hologram. A significant trade-off is that as the cone angle of the probe beam increases, the reconstruction error decreases but the optical aberrations increase. One of the more difficult challenges during scanning is to maintain a fixed focal point on the confocal apertures as the beam is tilted off the optical axis centerline. Further recommended advancements for the microscope are improving the optical lenses to provide pupil planes that are stationary during scanning and the miniaturization of the microscope using diffraction grating lenses instead of glass lenses for more practical applications. Determining the internal temperature of a flame by passing a focused laser beam through the flame is an example of a practical application. The CSLH microscope is uniquely capable of non-intrusively measuring the 3D temperature of a specimen given a single viewpoint window for scanning with applications in the physical and biological sciences.

Copies of author's previously published articles inserted. / Bibliography: p. 119-129. / xvi, 129, [58] p. : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / This thesis investigated the suitability of liquid crystal spatial light modulators as versatile computer controlled optical elements. The modulation characteristics were determined empirically and experimentally, and their performance as phase modulators tested in the two diverse applications of computer generated holography and phase aberration correction. Commercial liquid crystal panels from a video projector were used, chosen because of low cost, high resolution, computer controlled input, reconfigurability and ready availability. The panels were found to be more suited to amplitude than to phase modulation. Results show that the devices are versatile enough to be adapted to the two very different applications. / Thesis (Ph.D.)--University of Adelaide, Dept. of Physics and Mathematical Physics, 1998

Thesis (M.S.)--Rochester Institute of Technology, 1989. / Spine title: Correcting geometric distortion in holographic stereograms. Includes bibliographical references (leaves 37-39).