SACM - United States of America
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Item Restricted DIGITAL VOLUME REFLECTION HOLOGRAPHY: APPLICATION TO 3D MULTISPECTRAL DISPLAY(University of Dayton, 2024-12) Qissi, Saleha; Banerjee, ParthaThe aim of this research is to explore a new concept in holography, termed digital volume reflection holography, for implementing 3D displays, numerically and optically, with excellent color discrimination. Conventionally, digital holograms are transmission holograms, recorded with a CCD camera as the interference pattern between nominally co-propagating light from a reference and the object. Realizing that a digital volume reflection hologram can be simulated through periodic longitudinal extension of the digital transmission hologram, a wavelength-multiplexed composite digital volume reflection hologram is derived from respective simulated transmission holograms. Readout from the composite digital volume reflection hologram is numerically achieved using coupled wave theory, and the dependence of diffraction efficiency during reconstruction on incident angle of the reading beam, volume grating thickness and wavelength is studied. Alternatively, optical readout of digital volume reflection hologram is possible, by using a liquid crystal spatial light modulator as a holographic optical element. This is achieved by computing the optical field at the exit of a composite digital volume reflection hologram generated numerically from multiple digital transmission holograms recorded at different wavelengths, which is then appropriately introduced as an electrical input into the liquid crystal spatial light modulator, operated in both phase only and amplitude only modes. Also in this work, the composite digital volume reflection hologram is generated from point-based methods. The main advantage of the point-based method is its ability to capture 3D visual cues effectively; however, its key disadvantage is the computational volume. A layer-based method is used with point cloud method to reduce the computational intensity. Finally, realizing the importance of phase retrieval in the imaging of phase objects or objects with 3D topography, the composite digital volume reflection hologram is reconstructed using transport of intensity. Use of the transport of intensity equation is a recognized method to directly determine the true unwrapped phase from computed defocused intensities around the image or reconstruction plane. Numerical and experimental results using simple multispectral 3D surfaces using composite DVRH are presented.10 0Item Restricted Digital Volume Reflection Holography: Application to 3D Multispectral Display(University of Dayton, 2024-12) Qissi, Saleha; Banerjee, ParthaThe aim of this research is to explore a new concept in holography, termed digital volume reflection holography, for implementing 3D displays, numerically and optically, with excellent color discrimination. Conventionally, digital holograms are transmission holograms, recorded with a CCD camera as the interference pattern between nominally co-propagating light from a reference and the object. Realizing that a digital volume reflection hologram can be simulated through periodic longitudinal extension of the digital transmission hologram, a wavelength-multiplexed composite digital volume reflection hologram is derived from respective simulated transmission holograms. Readout from the composite digital volume reflection hologram is numerically achieved using coupled wave theory, and the dependence of diffraction efficiency during reconstruction on incident angle of the reading beam, volume grating thickness and wavelength is studied. Alternatively, optical readout of digital volume reflection hologram is possible, by using a liquid crystal spatial light modulator as a holographic optical element. This is achieved by computing the optical field at the exit of a composite digital volume reflection hologram generated numerically from multiple digital transmission holograms recorded at different wavelengths, which is then appropriately introduced as an electrical input into the liquid crystal spatial light modulator, operated in both phase only and amplitude only modes. Also in this work, the composite digital volume reflection hologram is generated from point-based methods. The main advantage of the point-based method is its ability to capture 3D visual cues effectively; however, its key disadvantage is the computational volume. A layer-based method is used with point cloud method to reduce the computational intensity. Finally, realizing the importance of phase retrieval in the imaging of phase objects or objects with 3D topography, the composite digital volume reflection hologram is reconstructed using transport of intensity. Use of the transport of intensity equation is a recognized method to directly determine the true unwrapped phase from computed defocused intensities around the image or reconstruction plane. Numerical and experimental results using simple multispectral 3D surfaces using composite DVRH are presented.7 0