Two collimated laser beams, wavelength O-514 μm are overlapped within a crystal of heavily iron doped lithium niobate to form a one-dimensional volume holographic grating, a few mm long, designed to behave as a highly selective filter at near infra-red wavelengths. A novel recording geometry is described and a variety of diagnostic experiments are undertaken to determine the main characteristics of the grating. A filter fabricated using this method is used to obtain single mode operation from a 1-55 μm semiconductor laser. The historical survey of holography contained in chapter one emphasizes the dynamic properties and applications of photorefractive recording materials. Standard results of two mathematical theories, kinematic and coupled-wave, are used in chapter two to predict the properties of a Bragg grating when replayed with infra-red light. Chapter three details the recording materials suitable for an infra-red filter, followed by a discussion on the concept of 'scaling'. The recording mechanism of iron doped lithium niobate, including its fixing and erasure process, is presented in chapter four as a basis for selecting the most advantageous crystal characteristics. Mathematical models describing the complex dynamic recording process in iron doped lithium niobate are introduced in chapter five. A novel recording geometry involving the use of two prisms is critically described in chapter six, from initial conception to final implementation. The performance of the grating as an infra-red filter is assessed in chapter seven by measuring the angular response of the transmitted and diffracted beams at a wavelength of 1-152 microns. Chapter eight discusses the applications for volume holographic filters, with particular reference to one example. In chapter nine general conclusions are drawn and future directions for research are suggested. A number of appendices are also included.

Through a holographic recording a property from the third dimension, the depth, is obtained in the form of a phase map of the incident light. One wavelength holography will have a unique phase for the depth range corresponding to the wavelength of the light and outside this range the real depth can not be resolved. By introducing more wavelengths to the measurement the unique phase combination of the waves will have a wider range and larger objects can be resolved. Up to six wavelengths can be simultaneous recorded by making them occupy different spatial frequencies. A set of spatial frequencies together describing a property of the wave is referred to as a lobe. For more than 6 wavelengths and a larger depth range produced by a more seldom repeated unique phase combination the individual waves will occupy the same frequencies, i.e. the lobes overlap. The separation of overlapping lobes is essential in order to make precise and time independent measurements of large and/or moving objects. To separate the lobes the complex fields, i.e. the phases together with the amplitudes, were simulated to propagate a distance and again recorded. The propagation leads to a phase shift of the spatial frequencies which reveals the complex fields in the case of two overlapping wavelengths. For three overlapping wavelengths the resolution, i.e spatial frequencies describing the object, has to be reduced in order to determine the individual complex fields. Since the propagation is a linear transformation for the frequencies that do not overlap, only the overlapping elements whose propagation is nonlinear produce new information. The new information gained is therefore independent of the number of wavelengths used which limits the exact determination of the fields to two wavelengths. Through the holographic recording another property of the complex field is obtained which is the superimposed individual intensities. This bounds the complex fields to certain values, i.e. restricts the possible amplitude of the waves. The recording in the two planes produces two intensity distributions which both must be satisfied by the complex fields. The optimization model for this was formulated and a simple optimization algorithm was implemented. Instead of an equality constraint of the intensities the inequality constraint was implemented, mainly due to that the optimization process was out of the scope of the thesis and the inequality constraint resulted in a simple implementation. The result pointed out important properties even though the optimization could not separate the fields satisfactorily for more than three wavelengths. The inequality constraint contains enough information to solve the case of three overlapping wavelengths.

Thesis (Ph. D.)--University of Washington, 1998. / Vita. Includes bibliographical references (leaves [120]-123).

Thesis--Karolinska Institutet. / Extra t.p. with thesis statement inserted. Four articles by the author reprinted from Acta odont. Scand. and Sc. ed. bull. in pocket. Includes bibliographical references (p. 31-34).

Thesis--Karolinska Institutet. / Extra t.p. with thesis statement inserted. Four articles by the author reprinted from Acta odont. Scand. and Sc. ed. bull. in pocket. Includes bibliographical references (p. 31-34).

Thesis (Ph. D.)--Physics, Georgia Institute of Technology, 2008. / Trebino, Rick, Committee Chair ; Kennedy, Brian, Committee Member ; Kuzmich, Alex, Committee Member ; Curtis, Jennifer, Committee Member ; Buck, John, Committee Member.

Thesis (Ph. D.)--University of Canterbury, 2006. / Typescript (photocopy). "August 2006." Includes bibliographical references (p. [167]-179) and index. Also available via the World Wide Web.

abstract: Off-axis electron holography (EH) has been used to characterize electrostatic potential, active dopant concentrations and charge distribution in semiconductor nanostructures, including ZnO nanowires (NWs) and thin films, ZnTe thin films, Si NWs with axial p-n junctions, Si-Ge axial heterojunction NWs, and Ge/LixGe core/shell NW. The mean inner potential (MIP) and inelastic mean free path (IMFP) of ZnO NWs have been measured to be 15.3V±0.2V and 55±3nm, respectively, for 200keV electrons. These values were then used to characterize the thickness of a ZnO nano-sheet and gave consistent values. The MIP and IMFP for ZnTe thin films were measured to be 13.7±0.6V and 46±2nm, respectively, for 200keV electrons. A thin film expected to have a p-n junction was studied, but no signal due to the junction was observed. The importance of dynamical effects was systematically studied using Bloch wave simulations. The built-in potentials in Si NWs across the doped p-n junction and the Schottky junction due to Au catalyst were measured to be 1.0±0.3V and 0.5±0.3V, respectively. Simulations indicated that the dopant concentrations were ~1019cm-3 for donors and ~1017 cm-3 for acceptors. The effects of positively charged Au catalyst, a possible n+-n--p junction transition region and possible surface charge, were also systematically studied using simulations. Si-Ge heterojunction NWs were studied. Dopant concentrations were extracted by atom probe tomography. The built-in potential offset was measured to be 0.4±0.2V, with the Ge side lower. Comparisons with simulations indicated that Ga present in the Si region was only partially activated. In situ EH biasing experiments combined with simulations indicated the B dopant in Ge was mostly activated but not the P dopant in Si. I-V characteristic curves were measured and explained using simulations. The Ge/LixGe core/shell structure was studied during lithiation. The MIP for LixGe decreased with time due to increased Li content. A model was proposed to explain the lower measured Ge potential, and the trapped electron density in Ge core was calculated to be 3×1018 electrons/cm3. The Li amount during lithiation was also calculated using MIP and volume ratio, indicating that it was lower than the fully lithiated phase. / Dissertation/Thesis / Doctoral Dissertation Physics 2015

This thesis is grounded in the theoretical discourses of art therapy and transpersonal psychology. The focus is on a single session of claywork, where a sculpture was made and discussed, leading to an understanding of some of the sculptor's central psychological issues. The overall aim of the research was to examine different hermeneutic perspectives on art therapy with clay sculpture in terms of how well they open up and do justice to the experience of the sculptor and the nature of the overall process. Within this there are two particular goals: Firstly, to examine the extent to which the holographic paradigm in comparison to other perspectives, allows a deeper access to, and deeper understanding of, transpersonal themes and processes; and secondly, to examine the extent to which processes within claywork can be understood as ritual activities. The research was a phenomenological-hermeneutic case study. The session was reduced to a narrative synopsis, and then a hermeneutically grounded thematic analysis was carried out using the theory of Transpersonal Feminism (Knight, 1997) and Schema-Focused Cognitive Therapy (young, 1990, 1994). The principal conclusions reached were that the holographic paradigm does add to our understanding of the experiences (personal and transpersonal) of the claywork, often beyond the scope of other art therapy perspectives. The image of the shaman is used as a metaphor for understanding the process of healing described within the holographic paradigm. Within the healing process, ritual plays an important role in the meaningful therapeutic activity of art therapy. The claywork expresses that the transpersonal struggle with archetypal forces within the collective unconscious is reflected on a personal level through individual conflicts and dilemmas within the personal unconscious. Indeed, these difficulties are viewed on both levels as 'stepping stones' on the path of spiritual development described by Engler (1984) and Welwood (1986).

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.