Seismology is the study of earthquakes and the Earth’s internal structure using seismic waves. Traditional seismology is constrained by the timing and location of seismic sources, and by the location of seismometers with which energy from the sources are recorded. Improvements in the global seismometer networks have reduced the latter constraint. Furthermore, recent advances into Seismic Interferometry (SI) have enabled detailed information about the Earth’s interior to be obtained using ambient seismic noise, hence even in areas with low natural seismicity. The most common approach to SI is to use the cross-correlation of ambient noise recordings to construct an estimate of the Green’s function between two seismometer locations. The Green’s function estimate is then analysed or inverted for seismic properties of the Earth. This method of noise interferometry is now a popular approach in earthquake seismology as in some situations it renders active seismic sources (earthquakes or synthesised explosions) obsolete, as subsurface information can be obtained even in times of seismic quiescence. This thesis investigates a different method: Source-Receiver Interferometry (SRI). SRI can be used to construct earthquake seismograms on seismometers that were not necessarily deployed when the earthquakes occurred - a form of ‘retrospective seismology’. This might be useful if, for example, we wish to analyse old earthquakes with newly installed seismometers. The application of SRI involves evaluating two interferometric integrals. The first integral is evaluated using ambient noise interferometry: at least 6 months of noise data is cross-correlated to estimate the Green’s functions between pairs of seismometers. These inter-receiver Green’s functions are then used as the “propagators” for SRI. Their role is to project earthquake signals recorded on a backbone array of seismometers to the location of a target sensor at which a new, novel earthquake seismogram is to be constructed - a form of spatial redatuming. To spatially redatum the earthquake data, the second interferometric integral is evaluated using either processes of correlation (resulting in correlation-correlation SRI) or convolution (correlation-convolution SRI). The method used depends on the relative location of the target sensors with respect to both the backbone seismometer array and the earthquake epicentre. The SRI process is completed by integrating (summing) over all projected earthquake signals. To regularise the spatial distribution of the projected earthquake data and to invoke this second interferometric integral more precisely, the backbone seismometers are embedded within 2D spatial Voronoi cells. New seismograms for 87 earthquakes were reconstructed on up to eight target sensors, seven of which were deployed when the earthquakes occurred and are used to test the success of the method by comparing with the SRI results with the directly-recorded seismograms. The seismogram reconstructions on the eighth target sensor are truly novel. The SRI method was developed to operate over two length scales. The first focusses on relatively small length scales in which the inter-station distance between the eight target sensors and the backbone array seismometers is between ~ 210 km and 540 km. Both correlation-correlation SRI and correlation-convolution SRI are used to reconstruct the earthquake seismograms on four of the same target sensors. Applying correlation-convolution SRI is shown to remove spurious signals associated with correlation-correlation SRI. Second, a significantly larger length scale is considered where a second set of target sensors are located up to 2420 km from a second backbone seismometer array. The correlation-correlation and correlation-convolution SRI methods are used in parallel to increase the spatial extent of the study. The quality of the SRI seismograms constructed is shown to depend on the quality of three components: 1) the SRI propagators constructed using ambient noise interferometry, 2) the earthquake signals recorded on the backbone seismometer array, and 3) the correlation (or convolution) functions that are summed in the second interferometric integral to construct the final SRI seismogram. The quality of each component is quantified by its signal-to-noise ratio and root-mean-square value, and criteria are proposed to obtain optimal earthquake seismogram reconstructions using SRI. SRI is most successful when the target sensors are located less than 540 km from the backbone array seismometers. Such SRI seismograms are being used to create a catalogue of new, ‘virtual’ earthquake seismograms that are available to complement real earthquake data for use in future earthquake seismology studies. An alternative approach to noise interferometry is also considered: the recordings from just 15 earthquakes are used to perform multidimensional deconvolution (MDD) to estimate the Green’s functions between pairs of seismometers. This is the first time such data has been used to perform MDD, which is valid in attenuating media and is thus theoretically more valid in earthquake seismology settings than correlational interferometry. The Green’s functions estimated using MDD are compared with those same Green’s functions estimated using ambient noise interferometry and the results are comparable on several occasions, despite using far fewer data for MDD. However, the quality of the results of MDD is significantly affected by the illumination of the receiver array from the earthquake sources. A greater density of earthquakes that sufficiently illuminates all backbone array seismometers is required to obtain accurate Green’s functions by MDD.

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.

A finalidade deste trabalho é aplicar a técnica de holografia em cristais fotorrefrativos para o estudo de propriedades mecânicas de microdispositivos, garantindo ainda a obtenção de uma geometria de arranjo holográfico simples e compacto. Foram feitas a análise de vibração e a análise de deformação de microdispositivos por meio da interferometria de média temporal e de dupla exposição, respectivamente. Como fontes de luz, foram utilizados diodos laser emitindo em 660nm, e um He-Ne laser emitindo em 632,8nm. Como meio fotorrefrativo de registro holográfico foi utilizado o cristal Bi12TiO20, (BTO) da família das selenitas. Foi proposto um arranjo óptico de holografia de reflexão do tipo Denisiuk, e a este arranjo foi adicionado um conjunto de lentes objetiva e ocular para formar uma configuração de microscópio composto, com o objetivo de obterem-se imagens holográficas de objetos de dimensões microscópicas. A gravação e a reconstrução do holograma se deram simultaneamente, devido à associação do cristal fotorrefrativo a uma câmera CMOS. Desta maneira, a observação dos hologramas foi feita em tempo real. Foram feitas, inicialmente, imagens de dupla exposição de piezorresistores MEMS (microelectromechanical systems), de geometria reduzida (2,96 x 0,6 mm2), e de dispositivos CMUT (Capacitive Micromachined Ultrasonic Transducers) com 640m de diâmetro. Através desta técnica foi possível medir deslocamentos de 0,33m a 4,3m. Foram obtidos também interferogramas de média temporal de cerâmicas e transdutores piezoelétricos, porém, iluminando apenas pequenas regiões destes objetos. Estas imagens mostraram qualidade razoável, indicando que é possível aplicar a técnica de interferometria em média temporal para objetos com amplitude de vibração entre 0,12m e 1,7m. Para investigar as potencialidades microscópicas foram feitas imagens de padrões de teste de resolução, onde foi possível visualizar estruturas com geometrias entre 2mm e 20m. / The aim of this work is to apply photorefractive crystals holography technique for the study of mechanical properties of micro-devices; it ensures obtaining a simple and compact geometry of holographic setup. Vibration and deformation analyses of micro-devices were performed using time average and double exposure interferometry, respectively. As light sources, it was used diode lasers emitting at 660nm, and He-Ne laser emitting at 632.8nm. As photorefractive holographic recording medium was used Bi12TiO20 (BTO) crystal, family of selenites. An optical setup of Denisiuk-type reflection holography was proposed, and this setup was added a set of objective and eyepiece lenses to form a compound microscope configuration, in order to obtain holographic images of objects with microscopic dimensions. Recording and reconstruction of the hologram occurred simultaneously, due to the combination of the photorefractive crystal to a CMOS camera. Thus, holograms observation occurs in real time. It was initially performed double exposure images of MEMS (microelectromechanical systems) piezoresistors, with reduced geometry (2.96 x 0.6 mm2), and CMUT (capacitive micromachined ultrasonic transducers) devices with 640m diameter. By this technique was possible measure displacements of 0.33m to 4.3m. Time average interferograms of Ceramics and piezoelectric transducers were also obtained, however, it illuminating only small regions of these objects. These images showed reasonable quality, indicating that it is possible apply the time average technique for objects with vibration amplitude between 0.12m e 1.7m. In order to investigate the microscopic potentialities images of resolution test chart were done, where it was possible to visualize structures with geometries between 20 m and 2mm.

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.

An atom interferometer is a sensitive device that has potential for many useful applications. Atoms are sensitive to electromagnetic fields due to their electric and magnetic moments and their mass allows them to be deflected in a gravitational field, thereby making them attractive for measuring inertial forces. The narrow momentum distribution of Bose-Einstein condensate (BEC) is a great asset in realizing portable atom interferometers. An example is a guided-wave atom interferometer that uses a confining potential to guide the motion of the condensate. Despite the promise of guided-wave atom interferometry with BEC, spatial phase and phase diffusion limit the contrast of the interference fringes. The control of these phases is required for successful development of a BEC-based guided-wave atom interferometer. This thesis analyses the guided-wave atom interferometer, where an atomic BEC cloud at the center of a confining potential is split into two clouds that move along different arms of the interferometer. The clouds accumulate relative phase due to the environment, spatially inhomogeneous trapping potential and atom-atom interactions within the condensate. At the end of the interferometric cycle, the clouds are recombined producing a cloud at rest and moving clouds. The number of atoms in the clouds that emerge depends on the relative phase accumulated by the clouds during propagation. This is investigated by deriving an expression for the probability of finding any given number of atoms in the clouds that emerge after recombination. Characteristic features like mean, standard deviation and cross-correlation function of the probability density distribution are calculated and the contrast of the interference fringes is optimized. This thesis found that optimum contrast is achieved through the control of total population of atoms in the condensate, trap frequencies, s-wave scattering length, and the duration of the interferometric cycle.

In this thesis work, we develop an optoelectronic holographic platform to facilitate otologists' ability to quantitatively study and diagnose disorders of the tympanic membrane (TM) and middle ear of humans in full-field-of-view. The holographic platform consists of a laser delivery system, a handheld interferometer, and corresponding software, which allow nanometer scale 3D measurements of deformations of the TM.

No description available.

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.

Orientador: Claudio Kitano / Banca: Ricardo Tokio Higuti / Banca: Luiz Antônio Perezi Marçal / Resumo: A interferometria óptica é uma técnica amplamente reconhecida por sua sensibilidade extremamente elevada para a medição de diversas grandezas físicas. Em particular, quando aplicada à medição de deslocamentos mecânicos, permite a detecção de movimentos micrométricos e manométricos em sólidos. Nesta dissertação, emprega-se um interferômetro de Michelson homódino para caracterizar atuadores piezoelétricos flextensionais e manipuladores piezoelétricos multi-atuados. Este trabalho se insere na linha de pesquisas desenvolvidas no laboratório de Optoeletrônica da FEIS-UNESP, dedicadas à concepção de novas técnicas de detecção interferométrica de fase óptica. Dentre as diversas famílias de métodos publicados na literatura, os métodos de demodulação baseados na análise do espectro do sinal fotodetectado têm recebido especial atenção na FEIS. Embora eficientes, estes métodos apresentam resolução limitada, não são capazes de caracterizar atuadores não-lineares e operam somente com formas de onda senoidais. Propõe-se, nesta dissertação, um método de detecção de fase óptica denominado de "Método de Segmentação do Sinal Amostrado", o qual é implementado no domínio do tempo. Este método, viabilizado pelos importantes recursos das técnicas de processamento digital de sinais, foi potencializado pela automatização das medições. Comparado aos procedimentos aplicados a experimentos anteriores na FEIS, cada medição equivale a 2500 medições no sistema antigo, permitindo o levantamento da curva de linearidade de um atuador com uma única medição. Além dessa, o método apresenta outras vantagens: é homódino, opera em malha-aberta, é imune ao desvanecimento do sinal, tem excelente resolução, ampla faixa dinâmica, opera com dispositivos não-lineares, detecta sinais com formas de onda arbitrárias, permite medir magnitude e fase do deslocamento... / Abstract: A interferometria óptica é uma técnica amplamente reconhecida por sua sensibilidade extremamente elevada para a medição de diversas grandezas físicas. Em particular, quando aplicada à medição de deslocamentos mecânicos, permite a detecção de movimentos micrométricos e manométricos em sólidos. Nesta dissertação, emprega-se um interferômetro de Michelson homódino para caracterizar atuadores piezoelétricos flextensionais e manipuladores piezoelétricos multi-atuados. Este trabalho se insere na linha de pesquisas desenvolvidas no laboratório de Optoeletrônica da FEIS-UNESP, dedicadas à concepção de novas técnicas de detecção interferométrica de fase óptica. Dentre as diversas famílias de métodos publicados na literatura, os métodos de demodulação baseados na análise do espectro do sinal fotodetectado têm recebido especial atenção na FEIS. Embora eficientes, estes métodos apresentam resolução limitada, não são capazes de caracterizar atuadores não-lineares e operam somente com formas de onda senoidais. Propõe-se, nesta dissertação, um método de detecção de fase óptica denominado de "Método de Segmentação do Sinal Amostrado", o qual é implementado no domínio do tempo. Este método, viabilizado pelos importantes recursos das técnicas de processamento digital de sinais, foi potencializado pela automatização das medições. Comparado aos procedimentos aplicados a experimentos anteriores na FEIS, cada medição equivale a 2500 medições no sistema antigo, permitindo o levantamento da curva de linearidade de um atuador com uma única medição. Além dessa, o método apresenta outras vantagens: é homódino, opera em malha-aberta, é imune ao desvanecimento do sinal, tem excelente resolução, ampla faixa dinâmica, opera com dispositivos não-lineares, detecta sinais com formas de onda arbitrárias, permite medir magnitude e fase do deslocamento ... / Mestre