This thesis presents a series of studies of thermalization and dissipation in a variety of strongly coupled systems. The main tool for these investigations is the Gauge/Gravity duality, which establishes a correspondence between a d+1-dimensional quantum theory of gravity and a d-dimensional quantum field theory. We study the decay rates of fluctuations around the thermal equilibrium in theories in non-commutative geometry. Rapid thermalization of such fluctuations is found and motivates the conjecture that the phenomena at the black hole horizon is described by non-local physics. In the same type of environment, we analyze the Langevin dynamics of a heavy quark, which undergoes Brownian motion. We find that the late-time behavior of the displacement squared is unaffected by the non-commutativity of the geometry. In a different scenario, we study the correlation functions in theories with quantum critical points. We compute the response of these quantum critical points to a disturbance caused by a massive charged particle and analyze its late time behavior. Finally, we analyze systems far-from-equilibrium as they evolve towards a thermal state. We characterize this evolution for systems with chemical potential by focusing on the ``strong subadditivity" property of their entanglement entropy. This is achieved on the gravity side by using time dependent functions for mass and charge in an AdS-Vaydia metric. / text

This work presents recent advances in photorefractive polymer composites towards improved efficiency, speed, persistence of holograms and sensitivity at both visible and near infrared wavelengths. Besides the pure performance characteristics, a thin-device approach is presented to reduce operating voltage of these devices to practical levels and these materials are analyzed in both reflection and transmission geometries.The thin device operating at 1.3kV holds erasable, Bragg holograms with 80% efficiency in addition to its video-rate response time. The transition of hologram state from 'thick' to 'thin' is analyzed in detail. On the near IR portion of spectrum, new photorefractive polymer composites have been developed that enable high performance operation at 845nm and 975nm. Utilizing our novel photorefractive materials we demonstrate large diffraction efficiency in four-wave mixing experiments and video-rate response times. A major step towards achieving submillisecond response times is obtained through recording photorefractive gratings with individual nanosecond pulses at 532nm. At 4 mJ/cm2 illumination, a maximum diffraction efficiency of 56% has been obtained with a build-up time of only 300 microseconds (t1). This fast response enables applications in optical processing requiring frame rates of 100Hz or more. Due to the short duration of the writing pulses, the recording is insensitive to vibrations. Combining molecules that have different frontier orbital energies in a copolymer system and utilizing thermal fixing approach has led to long grating lifetimes of more than several hours. Later, in this dissertation, two low-glass-transition photorefractive polymer composites are investigated in reflection geometry. 60% is diffraction efficiency is observed in 105 micron thick devices of a PVK based composite. The reflection holograms are more sensitive to reading angle and slight birefringence due to the poling of chromophores has proven to cause a Bragg mismatch.

Spectrum splitting is an approach to increasing the conversion efficiency of a photovoltaic (PV) system. Several methods can be used to perform this function which requires efficient spatial separation of different spectral bands of the incident solar radiation. In this paper several of holographic methods for implementing spectrum splitting are reviewed along with the benefits and disadvantages associated with each approach. The review indicates that a volume holographic lens has many advantages for spectrum splitting in terms of both power conversion efficiency and energy yield. A specific design for a volume holographic spectrum splitting lens is discussed for use with high bandgap InGaP and low bandgap silicon PV cells. The holographic lenses are modeled using rigorous coupled wave analysis, and the optical efficiency is evaluated using non-sequential raytracing. A proof-of-concept off-axis holographic lens is also recorded in dichromated gelatin film and the spectral diffraction efficiency of the hologram is measured with multiple laser sources across the diffracted spectral band. The experimental volume holographic lens (VHL) characteristics are compared to an ideal spectrum splitting filter in terms of power conversion efficiency and energy yield in environments with high direct normal incidence (DNI) illumination and high levels of diffuse illumination. The results show that the experimental VHL can achieve 62.5% of the ideal filter power conversion efficiency, 64.8% of the ideal filter DNI environment energy yield, and 57.7% of the ideal diffuse environment energy yield performance.

Abstract This research report details the design, construction, implementation and optimization of a quantitative movable flow visualization technique named Electronic Speckle Pattern Interferometry (ESPI). ESPI is a powerful visualisation technique that can allow for full flowfield analysis. It is thus possible to quantitatively determine the refractive index variation and hence the density variation in a compressible gas flow. Complementary results between previous work done and the current work shows the integrity of ESPI results Flowfields that were investigated included – candle flame, axis symmetric and nonaxis symmetric nozzles. Due to advanced CCD technology, there have been improvements in the overall image quality. Post processing of the images produced clearer images and hence better results. The technique was applied on multiple test rigs, proving its versatility

Este trabalho apresenta o estudo e o desenvolvimento de dois arranjos de interferometria holográfica utilizando como meio de registro holográfico cristais fotorrefrativos de Bi12TiO20 (BTO). O primeiro arranjo utiliza dois lasers de diodo sintonizáveis, emitindo em comprimentos de onda diferentes, em torno de 660 nm. Neste caso, a imagem holográfica do objeto estudado surge coberta de franjas de interferência que descrevem o relevo de sua superfície. O comprimento de onda sintético, que define a resolução do sistema na análise de superfícies, foi ajustado de modo a adequá-lo ao relevo da superfície estudada. A superfície de dois circuitos integrados e o relevo de uma moeda foram analisados, através de métodos de deslocamento de fase. O segundo arranjo gerou imagens holográficas e interferogramas, também com cristais BTO, através da montagem de Denisiuk para holografia de reflexão. Através da incorporação de um divisor de feixes polarizante, conseguiu-se melhorar a qualidade das imagens holográficas e reduzir o ruído. Medidas de deformação e vibração em pequenos objetos foram realizadas, assim como o estudo da dependência da intensidade do sinal holográfico sobre a orientação do cristal BTO. / This work presents the study and the development of two optical setups using Bi12TiO20 (BTO) photorefractive crystals for holographic interferometry. The first one employs two tunable diode lasers emitting at slightly different wavelengths around 660 nm. In this case, the holographic image of the studied object appears modulated by interference contour fringes. The resulting synthetic wavelength which determines the system resolution was selected in order to make it suitable for measuring the surface relief. The surfaces of two integrated circuits and a coin were analyzed with the help of phase shifting methods. The second BTO-based setup generated holographic images and interferograms through the Denisiuk scheme for reflection holography. The interferogram visibility and the optical noise were significantly reduced by using a polarizing beam splitter. Deformation and vibration measurements were performed, and the dependence of the reconstructed wave intensity on the BTO crystal orientation was studied as well.

The hearing process involves a series of physical events in which acoustic waves in the outer ear are transduced into acousto-mechanical motions of the middle ear, and then into chemo-electro-mechanical reactions of the inner ear sensors that are interpreted by the brain. Air in the ear canal has low mechanical impedance, whereas the mechanical impedance at the center of the eardrum, the umbo, is high. The eardrum or Tympanic Membrane (TM) must act as a transformer between these two impedances; otherwise, most of the energy will be reflected rather than transmitted. The acousto-mechanical transformer behavior of the TM is determined by its geometry, internal fibrous structure, and mechanical properties. Therefore, full-field-of-view techniques are required to quantify shape, sound-induced displacements, and mechanical properties of the TM. Shapes of the mammalian TMs are in millimeter ranges, whereas their acoustically-induced motions are in nanometer ranges, therefore, a clinically-applicable system with a measuring range spanning six orders of magnitude needs to be realized. In this Dissertation, several full-field measuring modalities are developed, to incrementally address the questions regarding the geometry, kinematics, and dynamics of the sound-induced energy transfer through the mammalian TMs. First, a digital holographic system with a measuring range spanning several orders of magnitude is developed and shape and 1D sound-induced motions of the TM are measured with dual-wavelength holographic contouring and single sensitivity vector holographic interferometry, respectively. The sound-induced motions of the TMs are hypothesized to be similar to those of thin-shells (with negligible tangential motions) and therefore, 3D sound-induced motions of the TM are estimated by combining measurements of shape and 1D motions. In order to test the applicability of the thin-shell hypothesis, and to obtain further details of complex spatio-temporal response of the TMs, holographic systems with multiple illumination directions are developed and shape and acoustically-induced vibrational patterns of the TMs are quantified in full 3D. Furthermore, to move toward clinical applications and in-vivo measurements, high-speed single-shot multiplexing holographic system are developed and 3D sound-induced motions of the TM are measured simultaneously in one single frame of the camera. Finally, MEMS-based high-resolution force sensing capabilities are integrated with holographic measurements to relate the kinematics and dynamics of the acousto-mechanical energy transfer in the hearing processes. The accuracy and repeatability of the measuring systems are tested and verified using artificial samples with geometries similar to those of human TMs. The systems are then used to measure shape, 3D sound-induced motions, and forces of chinchilla and human cadaveric TM samples at different tonal frequencies (ranging from 400 Hz to 15 kHz) simultaneously at more than 1 million points on its surface. A general conclusion is that the tangential motions are significantly (8-20 dB) smaller than the motions perpendicular to the TM plane, which is consistent with the thin-shell hypothesis of the TM. Force measurements reveal that frequency-dependent forces of the TM, are also spatially dependent so that the maximum magnitudes of the force transfer function of the umbo occurs at frequencies between 1.6 to 2.3 kHz, whereas the maximum values for other points on the TM surface occurs at higher frequency ranges (4.8 to 6.5 kHz). The Dissertation is divided into two Parts, each contains several Chapters. In the first Part, general overviews of the physiology of the human middle ear, along with brief summaries of previous studies are given, and basics of holographic interferometry are described. In the second Part, developments and implementations achieved in completion of this work are described in the form of a series of manuscripts. Finally, conclusions and recommendations for future work are provided.

Este trabalho apresenta o estudo e o desenvolvimento de dois arranjos de interferometria holográfica utilizando como meio de registro holográfico cristais fotorrefrativos de Bi12TiO20 (BTO). O primeiro arranjo utiliza dois lasers de diodo sintonizáveis, emitindo em comprimentos de onda diferentes, em torno de 660 nm. Neste caso, a imagem holográfica do objeto estudado surge coberta de franjas de interferência que descrevem o relevo de sua superfície. O comprimento de onda sintético, que define a resolução do sistema na análise de superfícies, foi ajustado de modo a adequá-lo ao relevo da superfície estudada. A superfície de dois circuitos integrados e o relevo de uma moeda foram analisados, através de métodos de deslocamento de fase. O segundo arranjo gerou imagens holográficas e interferogramas, também com cristais BTO, através da montagem de Denisiuk para holografia de reflexão. Através da incorporação de um divisor de feixes polarizante, conseguiu-se melhorar a qualidade das imagens holográficas e reduzir o ruído. Medidas de deformação e vibração em pequenos objetos foram realizadas, assim como o estudo da dependência da intensidade do sinal holográfico sobre a orientação do cristal BTO. / This work presents the study and the development of two optical setups using Bi12TiO20 (BTO) photorefractive crystals for holographic interferometry. The first one employs two tunable diode lasers emitting at slightly different wavelengths around 660 nm. In this case, the holographic image of the studied object appears modulated by interference contour fringes. The resulting synthetic wavelength which determines the system resolution was selected in order to make it suitable for measuring the surface relief. The surfaces of two integrated circuits and a coin were analyzed with the help of phase shifting methods. The second BTO-based setup generated holographic images and interferograms through the Denisiuk scheme for reflection holography. The interferogram visibility and the optical noise were significantly reduced by using a polarizing beam splitter. Deformation and vibration measurements were performed, and the dependence of the reconstructed wave intensity on the BTO crystal orientation was studied as well.

An autostereoscopic display based on a Holographic Optical Element(HOE) presents new opportunities for faithful 3D displaying but also presents potential new problems, such as: accuracy of 3D objects, interactivity and user perception. In this evaluation, which is the first of its kind for this type of display, I have explored and tested methods and tools for the evaluation of these potential problems. I have found that the visual quality is comparable to more common display types but with a significant visual delay due to the parallel rendering of graphics and the projectors significant input lag. From this I have concluded that the display system is not yet ready for its intended purpose, cranio-maxillofacial surgery planning. We need projectors with less input lag and preferably better optics. The software needs to be optimized for multimonitor rendering as well.

The laser-induced holographic gratings in the azo-dye-doped liquid crystals have been investigated by changing the temperature, and the concentration of the sample, the intensity of the two writing beams, and the polarization of probe beams. The cw Nd:YAG laser has been employed as the writing beams and the cw He-Ne laser has been employed as a real-time probe beam to detect the first order diffraction singals. The gratings are the results of photo-isomerization of azo dye and the structure alignment of liquid crystals. The model has been established to explain the first order diffraction signals, the mechanism of gratings formation and the temperature dependence.

Phase key, which uses optical encoding techniques for system security, plays an important role in optical storage, optical communication, and optical display. It employs a random phase generator with a volume hologram for optical encoding. The advantages of using phase keys for optical communication is: (1) it is hard to be duplicated and (2) it requires sensitively alignment to decode the desired signal. Thus, it ensures security of the optical system. However, the adjunctive challenge of using a phase key is the difficulty of alignment by users. In this paper, we propose a method for optical alignment of the phase key in a random phase encoded volume holographic storage system. In this method, a holographic correlator is applied to help the optical alignment of the phase key. It has been shown that the desired signal from the random phase encoded volume holographic storage system can be retrieved easily with high security.