Generated holographic stereograms in photorefractive polymer

Thesis (S.M.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2012.Cataloged from PDF version of thesis.Includes bibliographical references (p. 77-80).This thesis aims to assess the feasibility of an updatable three-dimensional display based on the direct fringe writing of computer-generated holographic gratings into a novel photorefractive polymer. The photorefractive polymer in question has been developed by Nitto Denko Technical Corporation and has many attractive properties for the 3-D display application, including long image persistence, rapid erasure, high diffraction efficiency, and large area; however, current holographic display systems based around its use involve interference methods that complicate their optical and computational architectures. The direct fringe writing architecture under question is poised as a simplifying and enhancing alternative to previous demonstrations of updatable holographic displays in photorefractive polymeric materials based around such conventional interference-based holographic stereogram techniques. In addition to simplifying optical architectures, direct fringe writing can allow for complete control of recorded hologram characteristics; interference fringes can be computed to simulate any arbitrary reference beam geometry and wavefront curvature. The system concept - comprised of fringe pattern generation on computer, fringe pattern transfer from SLM to photorefractive polymer, and spatial multiplexing for large-image generation - reintroduces accommodation cues to the resulting holographic images and represents a reduction of system footprint, complexity, and cost relative to the current interference-based systems. The adaptation of the Diffraction Specific Coherent Panoramagram fringe computation method - originally developed to drive AOM-based holographic displays at video rates while preserving all depth cues, including accommodation - to the current display architecture is presented and methods for direct fringe transfer from SLM to photorefractive polymer are depicted. Such methods for direct fringe writing are explored in simulation and experiment. Theoretical arguments for system performance are formulated in the context of a wave optics-based system analysis. Preliminary results of horizontal parallax-only images on this display are presented and directions for performance improvements and system extensions are explored.by Sundeep Jolly.S.M

Cylindrical beam volume holograms recorded in reflection geometry for diffuse source spectroscopy

Multimodal multiplex spectroscopy (MMS) has been demonstrated to increase the optical throughput of a spectrometer as opposed to that of conventional optical spectrometers and has been implemented using three-dimensional photonic crystals and spherical-beam volume holograms recorded in the transmission geometry as spectral diversity filters. While such efforts have resulted in compact and sensitive Fourier-transform holographic spectrometers, there still remains much room for performance improvements. Previous studies [6,7,9] have proven the utility of spherical-beam volume holograms recorded in the transmission geometry as spectral diversity filters for spectrometers. The role of the recording geometry in the performance of cylindrical-beam volume holograms as spectral diversity filters is investigated here. The transmission recording geometry is compared to the reflection recording geometry on the basis of the spectral operating range of the resultant spectral diversity filters.Faculty Mentor: Ali Adib

Holographic augmented reality : towards near-to-eye electroholography via guided wave acousto-optics

Thesis: Ph. D., Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2019Cataloged from PDF version of thesis.Includes bibliographical references (pages 121-128).Near-to-eye displays act to directly project imagery into a viewer's eye and can range in instantiation from extremely simple (such as an optical viewfinder) to more complex immersive displays for applications in virtual and augmented reality. Many current schemes for near-to-eye display employ stereoscopic techniques; however, such instantiations do not consistently present correct accommodation and vergence cues to the viewer, limiting their potential for seamless, comfortable augmented reality applications. Recent techniques based around light-field display methods show promise in the delivery of consistent depth cues although their applicability in presenting scenery with jointly high spatial and angular resolution is limited.Electroholographic displays have been shown to provide the highest degree of visual realism and consistency amongst cues to depth relative to all competing technologies for 3-D display, and several recent instantiations based around pixelated spatial light modulators have shown their utility for near-to-eye display applications. However, constraints on available space-bandwidth product in such pixelated modulators limit the usable system dtendue, resulting in reduced eyebox or field of view. In contrast, waveguide spatial light modulators offer the potential for displays with extremely high space-bandwidth product, compact form factors, and full-color operation via frequency-division multiplexing. This dissertation aims to assess the feasibility of waveguide-based electroholography for near-to-eye augmented reality display.In particular, such feasibility is assessed through (i) a static set of near-to- eye holograms computed via iterative Fresnel domain techniques and fabricated via grayscale electron-beam lithography and(2) the design and analysis of a fully monolithic photonic platform for transparent, flat-panel holographic display requiring no supporting optics and implemented via anisotropic leaky-mode coupling in conjunction with integrated Bragg-regime diffractive combiner optics in lithium niobate. Furthermore, this dissertation presents a fabrication modality for multiscale, transparent, flat-panel holographic video displays based around femtosecond direct laser writing. Methods for and results in the integration of anisotropic waveguides, volume Bragg reflection holograms, and surface acoustic wave transducers in a lithium niobate substrate are depicted.by Sundeep Jolly.Ph. D.Ph.D. Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Science

Status of Leaky Mode Holography

It will soon be a decade since leaky mode waveguide devices were presented as a solution for holographic video displays. This paper seeks to provide a brief, topical review of advances made during that time. Specifically, we review the new methods and architectures that have been developed over this period. This work draws primarily from papers seeking to present dynamic holographic patterns using mode coupling from indiffused waveguides on lithium niobate. The primary participants during this time period have been groups from the Massachusetts Institute of Technology, Brigham Young University, and Draper. We also describe the challenges that remain. The body of work reviewed speaks to the need for further development, but it also reaffirms that leaky mode waveguides continue to hold a unique place within spatial light modulation for holographic video displays.Draper IRAD for Multi-Scale Light FieldsUnited States. Air Force Research Laboratory Subaward for LWFP-HVD ProgramNational Science Foundation (U.S.). Career Grant (Award 1846477

Status of Leaky Mode Holography

It will soon be a decade since leaky mode waveguide devices were presented as a solution for holographic video displays. This paper seeks to provide a brief, topical review of advances made during that time. Specifically, we review the new methods and architectures that have been developed over this period. This work draws primarily from papers seeking to present dynamic holographic patterns using mode coupling from indiffused waveguides on lithium niobate. The primary participants during this time period have been groups from the Massachusetts Institute of Technology, Brigham Young University, and Draper. We also describe the challenges that remain. The body of work reviewed speaks to the need for further development, but it also reaffirms that leaky mode waveguides continue to hold a unique place within spatial light modulation for holographic video displays

Progress in fabrication of anisotropic Bragg gratings fabricated in lithium niobate via femtosecond laser micromachining

© 2018 SPIE. We have previously introduced a femtosecond laser micromachining-based scheme for the fabrication of anisotropic waveguides and isotropic Bragg reflection gratings in lithium niobate for application in future integrated-optic spatial light modulators. In this paper, we depict progress in fabrication and characterization of anisotropic Bragg reflection gratings fabricated in lithium niobate via Type I femtosecond laser-based permittivity modulation. We furthermore depict an electromagnetic analysis of such multilayer grating structures based around coupled-wave theory for thick holographic gratings