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.

Isolation of terrestrially-observed magnetic signals by restoring their diffusive loss due to subsurface electrical conductivity sufficiently correlates these signals with those derived from the Alfven ionospheric electron movement of refraction variation. Temporary magnetic observatories were established on a conductive sedimentary basin (with a sampling interval of 5 s) and on a resistive large igneous intrusion (with a sampling interval of 10 s). Conventional modeling techniques estimate and remove the effects of the magnetometer, geomagnetic diurnal changes, whorls (solar quiet current vortices), and some bays from the acquired signals. Conventional one-dimensional skin depth modeling estimates the diffusive attenuation. The residual magnetic signal and the diffusive filter (as applied to the topography) become quantities in the linear system estimation of the geoelectric subsurface. Angular frequency domain least squares solution of the equations yields an isolated magnetic anomaly spectrum. Interpretive refinement, by selection of the zero or near zero curvature onset of either the spectrum's real or imaginary component, critically prepares the signal solution for correlation to a pseudomagnetic anomaly signal. This is an independently-derived sequence of anomalous values derived from Global Positioning System (GPS) refracted ranges. Detailed application of the Biot-Savart law provides independent anomaly signals to which the magnetic anomalies correlations show great correlation improvement by the isolation. These correlation improvements are from 2% to 83% and 9% to 91% for the sedimentary basin and from 2% to 96% and 24% to 78% for the igneous intrusion.

This study discusses the three-dimensional refraction of progressive wave trains propagating over a bottom of circular concentric contours and the results are expressed in a polar coordinate. First, a general differential formulation of refraction is derived via three different methods: by transferring from its original Cartesian form to the polar coordinate, by applying the Fermat¡¦s principle in polar coordinate, and by applying the conservation of waves in polar coordinate. All three approaches give the same governing equation; hence, its correctness is verified. Based on this governing equation, the wave ray, the phase function, the constant phase line, and the refraction coefficient are all determined. In the present refraction problem for an originally uniform wave train propagating over a bottom of circular concentric contours, a few special features, including the cusps of constant phase lines due to the effect of bottom, and the envelope composed of these cusps, are present. All these refraction properties can be expressed in terms of both a snapshot and a time evolution of constant phase lines. In the lee side of the shoal, there exists a sheltered zone that is enclosed by the envelope of the cusps. In this zone, wave rays intersect and the corresponding caustic problem arises, and all possible combinations of intersecting rays are also specifically described in this study. The difficulty of classical ray theory for the caustic problem is overcome and the caustic phenomenon and its refraction coefficients are determined explicitly in this study.

Isolation of terrestrially-observed magnetic signals by restoring their diffusive loss due to subsurface electrical conductivity sufficiently correlates these signals with those derived from the Alfven ionospheric electron movement of refraction variation. Temporary magnetic observatories were established on a conductive sedimentary basin (with a sampling interval of 5 s) and on a resistive large igneous intrusion (with a sampling interval of 10 s). Conventional modeling techniques estimate and remove the effects of the magnetometer, geomagnetic diurnal changes, whorls (solar quiet current vortices), and some bays from the acquired signals. Conventional one-dimensional skin depth modeling estimates the diffusive attenuation. The residual magnetic signal and the diffusive filter (as applied to the topography) become quantities in the linear system estimation of the geoelectric subsurface. Angular frequency domain least squares solution of the equations yields an isolated magnetic anomaly spectrum. Interpretive refinement, by selection of the zero or near zero curvature onset of either the spectrum's real or imaginary component, critically prepares the signal solution for correlation to a pseudomagnetic anomaly signal. This is an independently-derived sequence of anomalous values derived from Global Positioning System (GPS) refracted ranges. Detailed application of the Biot-Savart law provides independent anomaly signals to which the magnetic anomalies correlations show great correlation improvement by the isolation. These correlation improvements are from 2% to 83% and 9% to 91% for the sedimentary basin and from 2% to 96% and 24% to 78% for the igneous intrusion.

In this thesis a consistent multipole theory is used to describe light propagation in nonabsorbing magnetic cubic and uniaxial crystals to the order of electric octopoles and magnetic quadrupoles. The first chapter extends Maxwell's equations for a vacuum to their macroscopic form in matter by including bound-source contributions as multipole expansions. From these the corresponding forms for D and H are obtained, which ensure origin-independence of Maxwell's equations. A multipole eigenyalue equation describing light propagation in a source-free homogeneous medium is then derived, which is the basic equation applied in this thesis. In the second chapter it is shown how, from the multipolar form of the propagation equation for transverse waves, expressions can be derived for the various birefringences that may be exhibited in macroscopic platelets of the medium, as introduced by Jones in the formulation of his M-matrix. The following chapter presents the derivation, by means of first-order perturbation theory, of the quantum mechanical expressions for the polarizability tensors which enter the eigenvalue wave equation. The origin independence of the expressions for the various observable quantities is then established. In the fourth chapter the independent components of the polarizability tensors are calculated for two selected crystal point groups, namely 622 and 432, by way of illustration. In chapter five the components calculated in the manner illustrated in the previous chapter are presented in tabular form. The Jones method outlined in chapter two is then applied to the crystal point group 6m2, again as an illustration of the method used to determine the optical effects displayed by this point group. Chapter five concludes with a table containing a listing of the predicted optical effects calculated in this way for all of the magnetic uniaxial and cubic point groups. The thesis concludes with chapter six, in which a summary of the results of the work undertaken is given, together with a discussion of factors influencing measurements of the predicted optical effects. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1997.

No description available.

No description available.

Optical spatial solitons in nematic liquid crystals, termed nematicons, have become an excellent test bed for nonlinear optics, ranging from fundamental effects to potential uses, such as designing and demonstrating all-optical switching and routing circuits in reconfigurable settings and guided-wave formats. Following their demonstration in planar voltage-assisted nematic liquid crystal cells, the spatial routing of nematicons and associated waveguides have been successfully pursued by exploiting birefringent walkoff, interactions between solitons, electro-optic controlling, lensing effects, boundary effects, solitons in twisted arrangements, refraction and total internal reflection and dark solitons. Refraction and total internal reflection, relying on an interface between two dielectric regions in nematic liquid crystals, provides the most striking results in terms of angular steering. In this thesis, the refraction and total internal reflection of self-trapped optical beams in nematic liquid crystals in the case of a planar cell with two separate regions defined by independently applied bias voltages have been investigated with the aim of achieving a broader understanding of the nematicons and their control. The study of the refraction of nematicons is then extended to the equivalent refraction of optical vortices. The equations governing nonlinear optical beam propagation in nematic liquid crystals are a system consisting of a nonlinear Schr¨odinger-type equation for the optical beam and an elliptic Poisson equation for the medium response. This system of equations has no exact solitary wave solution or any other exact solutions. Although numerical solutions of the governing equations can be found, it has been found that modulation theories give insight into the mechanisms behind nonlinear optical beam evolution, while giving approximate solutions in good to excellent agreement with full numerical solutions and experimental results. The modulation theory reduces the infinite-dimensional partial differential equation problem to a finite dynamical system of comparatively simple ordinary differential equations which are, then easily solved numerically. The modulation theory results on the refraction and total internal reflection of nematicons are in excellent agreement with experimental data and numerical simulations, even when accounting for the birefringent walkoff. The modulation theory also gives excellent results for the refraction of optical vortices of +1 topological charge. The modulation theory predicts that the vortices can become unstable on interaction with the nematic interface, which is verified in quantitative detail by full numerical solutions. This prediction of their azimuthal instability and their break-up into bright beams still awaits an experimental demonstration, but the previously obtained agreement of modulation theory models with the behaviour of actual nematicons leads us to expect the forthcoming observation of the predicted effects with vortices as well.

No description available.

The views expressed in this thesis are those of the author and do not relfect the offical policy or position of the Department of Defense or the U.S. Government. / Previous modifications were made to the Naval Postgraduate School (NPS) Lidar System to enable comparison of lidar returns with radiosonde vertical profiles. Inaccuracies due to flexing of the lidar mounting structure limited observation of correlation between lidar and balloon data. Reconstruction with anew telescope and integral mounting now provides stable overlap of laser illumination and receiver field-of-view while maintaining eye safety. This revised system permits more measurement of profile correlation. Both day and night lidar measurement series have been compared with concurrent radiosonde launches in the Monterey Bay area. Maximum ranges from clouds greater than 3500 meters by day and greater than 5000 meters by night have been achieved. Within this range comparison can be made with moderate accuracy with the temperature and pressure profile boundary layer ceiling. Recommendations are made for future enhancement of sensitivity of correlation.