Compact and sensitive spectrometers are of high utility in biological and environmental sensing applications. Over the past half century, enormous research resources are dedicated in making the spectrometers more compact and sensitive. However, since all works are based on the same structure of the conventional spectrometers, the improvement on the performance is limited. Therefore, this ancient research filed still deserves further investigation, and a revolutionary idea is required to take the spectrometers to a whole new level. The research work presented in this thesis focuses on developing a new class of spectrometers that work based on diffractive properties of volume holograms. The hologram in these spectrometers acts as a spectral diversity filter, which maps different input wavelengths into different locations in the output plane. The experimental results show that properly designed volume holograms have excellent capability for separating different wavelength channels of a collimated incident beam. By adding a Fourier transforming lens behind the hologram, a slitless Fourier-transform volume holographic spectrometer is demonstrated, and it works well under diffuse light without using any spatial filter (i.e., slit) in the input. By further design of the hologram, a very compact slitless and lensless spectrometer is implemented for diffuse source spectroscopy by using only a volume hologram and a CCD camera. More sophisticated output patterns are also demonstrated using specially designed holograms to improve the performance of the holographic spectrometers. Finally, the performance of the holographic spectrometers is evaluated and the building of the holographic spectrometer prototype is also discussed.

This dissertation combines various holographic techniques with application on the two- and three-dimensional imaging of ophthalmic tissue, fingerprints, and microsphere samples with micrometer resolution. Digital interference holography (DIH) uses scanned wavelengths to synthesize short-coherence interference tomographic images. We used DIH for in vitro imaging of human optic nerve head and retina. Tomographic images were produced by superposition of holograms. Holograms were obtained with a signal-to-noise ratio of approximately 50 dB. Optic nerve head characteristics (shape, diameter, cup depth, and cup width) were quantified with a few micron resolution (4.06 -4.8 microns). Multiple layers were distinguishable in cross-sectional images of the macula. To our knowledge, this is the first report of DIH use to image human macular and optic nerve tissue. Holographic phase microscopy is used to produce images of thin film patterns left by latent fingerprints. Two or more holographic phase images with different wavelengths are combined for optical phase unwrapping of images of patent prints. We demonstrated digital interference holography images of a plastic print, and latent prints. These demonstrations point to significant contributions to biometry by using digital interference holography to identify and quantify Level 1 (pattern), Level 2 (minutia points), and Level 3 (pores and ridge contours). Quantitative studies of physical and biological processes and precise non-contact manipulation of nanometer/micrometer trapped objects can be effectuated with nanometer accuracy due to the development of optical tweezers. A three-dimensional gradient trap is produced at the focus position of a high NA microscope objective. Particles are trapped axially and laterally due to the gradient force. The particle is confined in a potential well and the trap acts as a harmonic spring. The elastic constant or the stiffness along any axis is determined from the particle displacements in time along each specific axis. Thus, we report the sensing of small particles using optical trapping in combination with the digital Gabor holography to calibrate the optical force and the position and of the copolymer microsphere in the x, y, z direction with nm precision.

No description available.

Optical testing often requires a measurement of the phase difference between light from two different optical systems. One system is a master or reference system, and the other is a sample or test system. In the optical shop, the reference may be a precision optical surface and the test system may be a newly fabricated surface. A computer generated hologram is a geometric pattern that can be used as a precise reference in an optical test. Computer-generated holograms can be used to make reference systems that would be very difficult to make by other methods. Various encoding methods for making computer-generated holograms are discussed, and a new method is presented that can easily be used on image recorders intended for image processing applications. This general encoding method has many characteristics in common with earlier computer-generated holograms. Examples are given to demonstrate the properties of synthetic holograms and the differences among different encoding techniques. Geometric ray tracing is an essential part of the process of developing holograms for optical systems. A computer ray-trace code was developed to model the optical performance of equipment used in optical testing. This program was used to obtain numeric coefficients that describe the optical properties (optical path) needed to define a reference wavefront. A review of interferometer design leads to a discussion of how the hologram functions as a part of the interferometer and of the limitations to the computer-generated hologram. The diffraction pattern from the hologram, observed in the focal plane of a lens, is the key to understanding the use and limitations of the hologram in an interferometer. A detailed prescription is given for making a computer-generated hologram for a commercial interferometer designed for use with holograms. Problems of finding the proper focal point, the correct hologram size, and preparation of the final hologram image are discussed. An example of an actual test is included. Finally, an analysis of various errors encountered and the limitations of the methods used is presented. Within these limitations, computer-generated holograms can easily and routinely be used to test aspheric optical components.

In this dissertation we use digital holographic quantitative phase microscopy to observe and measure phase-only structures due to induced photothermal interactions and nanoscopic structures produced by photomechanical interactions. Our use of the angular spectrum method combined with off-axis digital holography allows for the successful hologram acquisition and processing necessary to view these phenomena with nanometric and, in many cases, subnanometric precision. We show through applications that this has significance in metrology of bulk fluid and interfacial properties. Our accurate quantitative phase mapping of the optically induced thermal lens in media leads to improved measurement of the absorption coefficient over existing methods. By combining a mathematical model describing the thermal lens with that describing the surface deformation effect of optical radiation pressure, we simulate the ability to temporally decouple the two phenomena. We then demonstrate this ability experimentally as well as the ability of digital holography to clearly distinguish the phase signatures of the two effects. Finally, we devise a pulsed excitation method to completely isolate the optical pressure effect from the thermal lensing effect. We then develop a noncontact purely optical approach to measuring the localized surface properties of an interface within a system using a single optical pressure pulse and a time-resolved digital holographic quantitative phase imaging technique to track a propagating nanometric capillary disturbance. We demonstrate the method's ability to accurately measure the surface energy of pure media and chemical monolayers formed by surfactants with good agreement to published values. We discuss the possible adaptation of this technique to applications for living biological cell membranes.

The main objective of this master’s thesis is to investigate the possibility of applying spatially-filtered continuous-wave acoustic tomography to the detection of breast cancer. A continuous acoustic wave is transmitted through the specimen in this tomographic imaging method. Any scattered waves that do not positively contribute to the projection are filtered out using an aperture. There is evidence to suggest that cancerous lesions in the breast have a higher speed of sound than surrounding tissues. This imaging method produces two tomograms of the specimen simultaneously: one showing the internal speed of sound, and the other showing the internal acoustic attenuation coefficient. There is the possibility for a third imaging modality, acoustic dispersion tomography, to be applied to this imaging method. Two proof-of-concept prototype spatially-filtered continuous-wave acoustic tomography scanners were designed and built: one that uses a collimated beam to interrogate the specimen, and another that uses a confocal beam. A least-squares tomographic reconstruction algorithm was chosen to reconstruct the tomograms this method creates. A prostate phantom and a breast phantom were imaged with the confocal tomographic scanner. The tomograms of the prostate phantom show two 1 cm lesions which are consistent with information from the phantom manufacturer. Further work is required to properly validate the speed of sound and acoustic attenuation measurements this method produces. / Graduate

In this thesis, we study the energy extraction from rotating black holes in anti-de Sitter (AdS) spacetime (Kerr-AdS black holes), via the Blandford-Znajek (BZ) process. The motivation is the anti-de Sitter/conformal field theory (AdS/CFT) correspondence which provides a duality between gravitational physics in asymptotically AdS spacetimes and lower dimensional boundary field theories. The BZ process operates via a force-free magnetosphere around black holes and the rotational energy of the black hole is extracted electromagnetically in the form of Poynting flux. The major part of the thesis is devoted to obtaining force-free solutions in the Kerr-AdS background, which generalize traditional BZ solutions in the asymptotically flat Kerr background. Given the solutions, we use the AdS/CFT to infer dual descriptions in terms of the boundary field theory, which hopefully will lead to a better understanding of the energy extraction for rotating black holes. / Graduate

The premise of this thesis is that the ???concrete holographic image???, a laser transmission hologram which has an object or a hologram of an object as its subject, has unique spatial and temporal properties which can suggest a plurality of tenses to a viewer. There is a lack of comprehensive analysis of the holographic representational system within art related theoretical and critical writing and a tendency to analyse individual works only in terms of generalities which apply to the concepts surrounding the holographic medium. While these form an important background for art image production, in some cases corresponding to artists works, the existing written material on the subject is inadequate as a model from which to draw the all important temporal conclusions. To date the critical reception of holograms has made no mention of acuity, the size of the viewing frustum, the depth of the image and scant mention of interference phenomena which are the intrinsic factors which I believe precipitate temporal illusions. Therefore this thesis examines the concrete holographic image in great detail on its own terms, firstly through theories of the basic image forming phenomena of interference and diffraction and secondly through the techniques of production as they have been adapted for the making of my art works. The extent of the metaphorical and allegorical potential of the spatial and temporal properties of the concrete holographic image are put to the ultimate test in a commission for St Brigid???s Church, Coogee. The Shrine of the Sacred Heart commission for St Brigid???s requires a concrete holographic image to facilitate devotion to the Sacred Heart. The Sacred Heart is not a physical thing but a complex, evolving spiritual entity with a realist pictorial history.

Thesis (Ph.D.) -- University of Western Sydney, 2001. / "Submitted in fulfilment of requirements for the degree of Doctor of Philosophy, School of Engineering and Industrial Design, University of Western Sydney" Includes bibliography.

Thesis (Ph. D.)--University of Washington, 1997. / Vita. Includes bibliographical references (leaves [161]-163).