Holographic Display Research Papers - Academia.edu (original) (raw)

Featured Application: The proposed method is applicable for static 3D advertising and holographic packaging. Abstract: A fast calculation method for the full parallax high-resolution hologram is proposed based on the elemental light field image (EI) rendering. A 3D object located near the holographic plane is firstly rendered as multiple EIs with a pinhole array. Each EI is interpolated and multiplied by a divergent sphere wave and interfered with a reference wave to form a hogel. Parallel acceleration is used to calculate the high-resolution hologram because calculation of each hogel is independent. A high-resolution hologram with the resolution of 20,0000×20,0000 pixels is calculated only within 8 minutes. Full parallax high-resolution 3D displays are realized by optical reconstructions.

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- Digital Holography, Holographic Display

A digital hologram is recorded by a 2D CCD array by superposition of the wavefield reflected or scattered from a scene and a coherent reference wave. If the recorded digital hologram is fed to a spatial light modulator (SLM) and this is illuminated by the reference wave, then the whole original wavefield can be reconstructed. The reconstructed wavefield contains phase and intensity distributions, which means it is full 3D, exhibiting such effects as depth and parallax. Therefore, the concept of digital holography is a promising approach to 3D-TV. In one of our previous works the preliminaries of an all-digital-holographic approach to 3D-TV were given. Here one of our approaches is experimentally verified and its capabilities and limitations are investigated.

- by Mostafa Agour
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- Visualization, Digital Holography, Virtual Environment, Image Reconstruction
- by SIAK KOR CHEW
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- Information Technology, Technology, Construction Technology, RFID

Researchers have developed a new approach that improves the image quality and contrast for holographic displays. [41] In a new report on Science Advances, Matz Liebel and a research team at the Barcelona Institute of Science and Technology and the Massachusetts General Hospital in Spain and the U.S. reported an imaging approach to recover the full electric field of fluorescent light using single-molecule sensitivity. [40] A six-minute holographic movie would take just over 800 hours to draw, the researchers reckon. [39] In conventional holography a photographic film can record the interference pattern of monochromatic light scattered from the object to be imaged with a reference beam of un-scattered light. [38] The scientists used the quantum nature of the electron-light interaction to separate the electron-reference and electron-imaging beams in energy instead of space. [37] A holographic acoustic tweezers (HAT) system has been used to suspend up to 25 objects in mid-air simultaneously. [36] Holography is a powerful tool that can reconstruct wavefronts of light and combine the fundamental wave properties of amplitude, phase, polarization, wave vector and frequency. [35] Physicist Artem Rudenko from Kansas State University and his colleagues pondered how to improve the images of viruses and microparticles that scientists get from X-rays. [34] A team of materials scientists from Penn State, Cornell and Argonne National Laboratory have, for the first time, visualized the 3-D atomic and electron density structure of the most complex perovskite crystal structure system decoded to date. [33] Hydrogen-powered electronics, travel, and more may be a step closer thanks to the work of a collaborative team of scientists in Japan. [32]

- by George Rajna
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- Holographic Display

Phase-only holographic projection has prompted
a great deal of research and has often been cited as a desirable
method of 2-D image formation, since such a technique offers
a number of advantages over conventional imaging projection
technology [1], [2]. Although holographic image formation was
demonstrated some forty years ago [3], efforts at realizing a
real-time 2-D video projection system based on this technique
have not been successful, principally due to the computational
complexity of calculating diffraction patterns in real time and
the poor quality of the resultant images. In this paper, a new
approach to hologram generation and display is presented which
overcomes both of these problems, enabling—for the first time—a high-quality real-time holographic projector.

- by Edward Buckley
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- Digital Holography, Laser, Optical Communication, LCOS

“THE GALAXY DISTRIBUTION IS IN CONCENTRIC CIRCLES AROUND THE EARTH. A SITUATION THAT DOES NOT OCCUR AROUND ANY OTHER POINT IN THE UNIVERSE.” IS RATHER OBVIOUS. ALSO THE ONLY TWO ANOMALIES IN THE UNIFORM BACKGROUND RADIATION FORM AN X... more

- by MIKE EMERY
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- Religion, History, Earth Sciences, Physics

Metamaterials are artificial materials, made by microscopic unit cells and projected to exhibit specific macroscopic properties, e.g. they can be designed in order to show a negative refractive index or a superluminal wave propagation. During the last decade, the interest in electromagnetic
metamaterials has been grown because of their possible applications, such as for antennas, transmission lines, lenses, cloaking devices etcetera. In this work we deal specially with metasurfaces, i.e. thin artificial screens or "2D metamaterials". In particular, we analyze how to express the
Huygens' Principle and the Boundary Conditions using the ElectroMagnetic Potentials, also considering the relativistic case. Starting from the Boundary Conditions we derive a circuit model for the project of a screen whose permittivity varepsilon\varepsilonvarepsilon and permeability mu\mumu are assigned. In the last chapters we wonder about the possibility of using metasurfaces in order to realize a holographic television or a hypothetical invisibility cloak.

The last two decades have seen the emergence and steady development of tangible user interfaces. While most of these interfaces are applied for input—with output still on traditional computer screens—the goal of programmable matter and actuated shape-changing materials is to directly use the physical objects for visual or tangible feedback. Advances in material sciences and flexible display technologies are investigated to enable such reconfigurable physical objects. While existing solutions aim for making physical objects more controllable via the digital world, we propose an approach where holograms (virtual objects) in a mixed reality environment are augmented with physical variables such as shape, texture or temperature. As such, the support for mobility forms an important contribution of the proposed solution since it enables users to freely move within and across environments. Furthermore, our augmented virtual objects can co-exist in a single environment with programmable matter and other actuated shape-changing solutions. The future potential of the proposed approach is illustrated in two usage scenarios and we hope that the presentation of our work in progress on a novel way to realise tangible holograms will foster some lively discussions in the CHI community.

- by Beat Signer and +1
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- Information Systems, Engineering, Robotics, Computer Science

Progress in image sensors and computation power has fueled studies to improve acquisition, processing, and analysis of 3D streams along with 3D scenes/objects reconstruction. The role of motion compensation/ motion estimation (MCME) in 3D TV from end-to-end user is investigated in this chapter. Motion vectors (MVs) are closely related to the concept of disparities, and they can help improving dynamic scene acquisition, content creation, 2D to 3D conversion, compression coding, decompression/decoding, scene rendering, error concealment, virtual/augmented reality handling, intelligent content retrieval, and displaying. Although there are different 3D shape extraction methods, this chapter focuses mostly on shape-from-motion (SfM) techniques due to their relevance to 3D TV. SfM extraction can restore 3D shape information from a single camera data.

- by Vania V Estrela
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- Computer Science, Computer Graphics, Human Computer Interaction, Computer Vision
- by Sean F Johnston
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- History of Science and Technology, Russian Studies, Optics, Visual Studies

Holographic Displays (HDs) provide 3D images with all natural depth cues via computer generated holograms (CGHs) implemented on spatial light modulators (SLMs). HDs are coherent light processing systems based on interference and diffraction, thus they generally use laser light. However, laser sources are relatively expensive, available only at some particular wavelengths and difficult to miniaturize. In addition, highly coherent nature of laser light makes some undesired visual effects quite evident, such as speckle noise, interference due to stray light or defects of optical components. On the other hand, LED sources are available in variety of wavelengths, has small die size, and no speckle artifact. However, their finite spatial size introduce some degree of spatial incoherence in an HD system and degrade image resolution, which is the subject of the study in this paper. Our theoretical analysis indicates that the amount of resolution loss depends on the distance between hologram and SLM image planes. For some special configurations, the source size has no effect at all. We also performed experiments with different configurations using lasers and LEDs with different emission areas that vary from 50 µm to 200 µm, and determined Contrast Transfer Function (CTF) curves which agree well with our theoretical model. The results show that it is possible to find configurations where LEDs combined with pinholes almost preserve natural resolution limit of human eye while keeping the loss in light efficiency within tolerable limits.

- by vahid pourreza ghoushchi and +1
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- Digital Holography, LED Lighting, Coherence, Spatial Coherence

This paper assesses the ergonomics of the air tap, a 3D gesture used to interact with the Hololens™, a head-mounted optical see-through display being developed by Microsoft™. After reviewing ergonomics literature we found the air tap appeared to be outside of known anthropometric and biomechanical limits and tolerances. Because the Hololens was unavailable for testing at the time of writing, the air tap was evaluated using methods that support general, observational data. The Rapid Entire Body Assessment (REBA), Rapid Upper Body Assessment (RULA) and Novel Ergonomic Postural Assessment (NERPA) methods were used to assess the gesture as observed in four videos. For all methods, higher scores suggested further investigation was required to avoid risk of developing musculoskeletal disorders. Although the neck trunk and leg portion of the REBA score was low, the arm and wrist portions gained more points. This was further reflected in overall high RULA and NERPA scores which focused more on the upper region of the body. Although these findings cannot be used to accurately assess whether the air tap suffers from poor ergonomics or puts the user at risk of developing musculoskeletal disorders, they do suggest the gesture might benefit from a more thorough investigation. This paper concludes by proposing future research into developing and validating an ergonomic framework designers and developers can use to develop 3D gestures.

- by Jed Looker
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- Ergonomics, Digital Holography, Interaction Design, Holography

Based on previous prototype of the Real time 3D holographic display developed last year, we developed a new concept of auto-stereoscopic multiview display (64 views), wide angle (90°) 3D full color display. The display is based on a RGB laser light source illuminating a DMD (Discovery 4100 0,7") at 24.000 fps, an image deflection system made with an AOD (Acoustic Optic Deflector) driven by a piezo-electric transducer generating a variable standing acoustic wave on the crystal that acts as a phase grating. The DMD projects in fast sequence 64 point of view of the image on the crystal cube. Depending on the frequency of the standing wave, the input picture sent by the DMD is deflected in different angle of view. An holographic screen at a proper distance diffuse the rays in vertical direction (60°) and horizontally select (1°) only the rays directed to the observer. A telescope optical system will enlarge the image to the right dimension. A VHDL firmware to render in real-time (16 ms) 64 views (16 bit 4:2:2) of a CAD model (obj, dxf or 3Ds) and depth-map encoded video images was developed into the resident Virtex5 FPGA of the Discovery 4100 SDK, thus eliminating the needs of image transfer and high speed links

- by Luigi Loreti
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- AOD, DMD, Holographic Display

Les artistes ont exploré l’holographie, comme système de représentation, dès la fin des années 60. Mais, encore aujourd’hui, l’analyse esthétique de cette forme d’imagerie spatiale basée sur l’interférence et la diffraction lumineuses reste peu développée. Les ambiguïtés perceptuelles de ce type d’images, dues à leur opacité lumineuse, leur présence fantomatique à la fois haptique et visuelle ou leur expansion perspective hors de la surface du support, finissent par créer une catégorie esthétique en soi. Ces images, qui continuent à déranger et fasciner à la fois, apportent effectivement bien autre chose que leur supposé réalisme tridimensionnel photographique : elles apportent une esthétique de l’effet holographique. On la retrouve de plus en plus disséminée à travers divers genres artistiques, en arts plastiques et médiatiques, en arts scéniques et théâtre optique, en présentation muséologique, et bien sûr dans le cinéma de science-fiction en 3D

- by Polat DALKIRAN
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- Digital Holography, Holography, Holographic Display, Holomap

We propose a full color computer generated holographic near-eye display (NED) based on white light illumination. The method inspired from color rainbow holography is used for calculation of 2D and 3D color holograms. The parameters of the color hologram calculation are designed based on the parameters of the spatial light modulator (SLM) with 4K resolution. A slit type spatial filter is designed in frequency domain to extract red, green and blue frequency components for full color display. A NED system including a white light source, an achromatic collimating lens, a 4K SLM, a 4f optical filtering system, and an achromatic lens as eyepiece is designed and developed. The main contribution of this paper is the first time to apply the rainbow holography concept to the dynamic full color NED with a compact display system. The optical experiments prove the feasibility of the proposed method.

- by Hongbo Zhang
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- Digital Holography, Holographic Display

One of the main drawbacks of Digital Holography (DH) is the coherent nature of the light source, which severely corrupts the quality of holographic reconstructions. Although numerous techniques to reduce noise in DH have provided good results, holo-graphic noise suppression remains a challenging task. We propose a novel framework that combines the concepts of encoding multiple uncorrelated digital holograms, block grouping and collaborative filtering to achieve quasi noise-free DH reconstructions. The optimized joint action of these different image-denoising methods permits the removal of up to 98% of the noise while preserving the image contrast. The resulting quality of the hologram reconstructions is comparable to the quality achievable with non-coherent techniques and far beyond the current state of art in DH. Experimental validation is provided for both single-wavelength and multi-wavelength DH, and a comparison with the most used holographic denoising methods is performed.

- by Pietro Ferraro and +2
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- Digital Holography, Holography, Holography Laser Projection, Holographic Display

In this study, we demonstrate a practical synthetic hologram with a size of 30 mm × 30 mm at resolution of 94340 × 94340. The high-definition large-scale computer-generated full-parallax synthetic hologram is achieved through frequency mosaic with different perspective images. The sparsity characteristics mosaic frequency of full parallax synthetic hologram is analyzed for reducing the complexity of computation. Following elimination of the sparsity, the hologram is calculated by normalization of 2D inverse Fourier transform of the mosaic frequency. The error and object point size are analyzed and we conclude that the error is sufficiently small for human visual perception given that parallax angle and object depth are within acceptable limits.

Proximity detection systems have been proposed as a potentially beneficial method for increasing the eye-safe luminous flux of laser-based pico-projectors. In this letter, it is shown that, while the benefit for panel-based systems could... more

- by Edward Buckley
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- Laser, Optical Communication, Display Technology, Laser Safety

It is shown that the lens count in a Fourier holographic projector can be reduced by encoding the equivalent lens
power in sets of Fresnel holograms. By using appropriately calculated Fresnel holograms in a reflective configuration
to effectively share a lens between the beam-expansion and demagnification stages of a holographic projector, a
reduction in lens count from four to one is demonstrated.

- by Edward Buckley
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- Optics, Digital Holography, Optical Communication, LCOS

The history of holography, the technology of three-dimensional imaging that grew rapidly during the 1960s, has been written primarily by its historical actors and, like many new inventions, its concepts and activities became surrounded by myths and myth-making. The first historical account was disseminated by the central character of this paper, George W. Stroke, while a professor of Electrical Engineering at the University of Michigan. His claims embroiled several workers active in the field of holography and information processing during the 1960s, but transcended personality conflicts: they influenced the early historiography of holography and the awarding of the Nobel Prize for Physics to Dennis Gabor in 1971. An extended discussion of these episodes, based on archival research, publications analysis and interviews with participants, reveals the importance and extraordinary allure of intellectual priority for practicing scientists, and how its history and explanations are woven from multiple accounts and contemporary interpretations.

- by Sean F Johnston
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- History, History of Science and Technology, Optics, Philosophy of Science

Dr. Denis Gabor most probably could not think of every usage of the hologram when he invented it, but he might had a strong feeling that he opened a new window for human being. History has shown that it was not only a scientific discovery, but it also led to a new philosophical explanation of the universe. Although it has not been a century, the technology of the holography already passed the horizon of his vision. Countless inventions and applications on holography have had remarkable influence on our daily lives. We have been using holograms in many places such as security, entertainment, measurement, training and so on. Why wouldn"t we use it for our most essential need which was map? As cartographers we have been discussing this question for more than ten years. Finally, we could achieve to find a new way of presentation of cartographic productions. The restrictions of the conventional medium, the paper, have not obstructed the cartographers to manufacture more visual contents and cognitive products, by using the power of the computers which is unquestionable. The rise of Paper-Era is reaching the saturation point and has been limiting the artists, publishers and cartographers. In this article, we will discuss the usage of holography in a cartographic perspective; interrogate the advantages and disadvantages of the hologram as a hard copy medium, evaluate a prototype of holographic map which is produced by General Command of Mapping, Turkey and exposed by Hangyo International Corp., Korea Republic. Finally what we suggest the future of cartographic publishing.

We report about the implementation of the 10Megapixel phase-only liquid crystal on silicon spatial light modulator for the visible and shortwave infrared spectral bands. The pixel pitch of the SLM is less than 4 micron. Experimental data... more

In digital holography (DH) a mixture of speckle and incoherent additive noise, which appears in numerical as well as in optical reconstruction, typically degrades the information of the object wavefront. Several methods have been proposed in order to suppress the noise contributions during recording or even during the reconstruction steps. Many of them are based on the incoherent combination of multiple holographic reconstructions achieving remarkable improvement, but only in the numerical reconstruction i.e. visualization on a pc monitor. So far, it has not been shown the direct synthesis of a digital hologram which provides the denoised optical reconstruction. Here, we propose a new effective method for encoding in a single complex wavefront the contribution of multiple incoherent reconstructions, thus allowing to obtain a single synthetic digital hologram that show significant speckle-reduction when optically projected by a Spatial Light Modulator (SLM).

- by Pietro Ferraro
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- Holography, Artifacts, ASTRONAUTS, Optical physics

Detection of Stealth warships using Digital Image Processing systems.pdf

- by Saikat Saha
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- Digital Holography, Digital Image Processing, Robots, Radar Systems

Six press articles and one course flyer about holography in NYC in 1975. four of the articles are press articles about Holography '75: The First Decade at the International Center of Photography (ICP), curated by Jody Burns. Article... more

- by Joseph Burns
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- Art History, History of Science, Holographic Display
- by Hongbo Zhang
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- 3d Displays, Holographic Display

The basic idea of a hologram is an apparition of something that does not exist but appears as if it was just in front of our eyes. These illusion techniques were invented a long time ago. The philosopher and alchemist Giovanni Battista della Porta invented an effect that was later developed and brought to fame by Prof. J. H. Pepper (1821–1900) and applied in theatrical performances. The innovation nowadays consists in the adopted technology to produce them. Taking advantage of the available digital technologies, the challenge we are going to discuss is using holograms in the museum context, inside showcases, to realize a new form of scenography and dramaturgy around the exhibited objects. Case studies will be presented, with a detailed analysis of the EU project CEMEC (Connecting Early Medieval European Collections), where holographic showcases have been designed, built and experimented in EU museums. In this case, the coexistence in the same space of the real artifact and the virtu...

- by Eva Pietroni
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- Computer Science, Informatics, Art, Evaluation Research

The currently secondary education needs the contribution of new techno-pedagogical resources, where the resource, teaching and learning skills are integrated to motivate students in their learning. For this reason, the field of holographics is presented as a dynamic alternative to the growing use of image projectors. However, these resources are not available to teachers and educational institutions because of their high costs. This research seeks to show how led-based technologies can be applied in secondary education, so allow the classroom attention of students and improve their interest in learning through the use of the 3D Holographic LED-Fan Display. In this way, the objective is to improve the student's motivation for learning using current resources according to the realities of the current context of education, which may not have availability of mobile devices due to their high costs, thus they have not been considered for the present study. The research approach is a mixed methodology combining qualitative and quantitative information through an educational study case applied to the Kléber Franco Cruz School with the intervention of pre-professional practices carried out by the Technical University of Machala in Ecuador, through the realization of an integrative knowledge project with students with different profiles according to their curriculum, in order to face the different challenges of teaching.

- by Mauricio Xavier Prado Ortega and +2
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- Teaching and Learning, Environmental Education, Holographic Display

Featured Application: The proposed technique has potential for head mounted near-eye VR or AR applications. Abstract: A fast computer-generated holographic method with multiple projection images for a near-eye VR (Virtual Reality) and AR (Augmented Reality) 3D display is proposed. A 3D object located near the holographic plane is projected onto a projection plane to obtain a plurality of projected images with different angles. The hologram is calculated by superposition of projected images convolution with corresponding point spread functions (PSF). Holographic 3D display systems with LED as illumination, 4f optical filtering system and lens as eyepiece for near-eye VR display and holographic optical element (HOE) as combiner for near-eye AR display are designed and developed. The results show that the proposed calculation method is about 38 times faster than the conventional point cloud method and the display system is compact and flexible enough to produce speckle noise-free high-quality VR and AR 3D images with efficient focus and defocus capabilities.

- by Hongbo Zhang
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- Holographic Display

A novel full-color autostereoscopic three-dimensional (3D) display system has been developed using color-dispersion-compensated (CDC) synthetic phase holograms (SPHs) on a phase-type spatial light modulator. To design the CDC phase holograms, we used a modified iterative Fourier transform algorithm with scaling constants and phase quantization level constraints. We obtained a high diffraction efficiency (~90.04%), a large signal-to-noise ratio (~9.57dB), and a low reconstruction error (~0.0011) from our simulation results. Each optimized phase hologram was synthesized with each CDC directional hologram for red, green, and blue wavelengths for full-color autostereoscopic 3D display. The CDC SPHs were composed and modulated by only one phase-type spatial light modulator. We have demonstrated experimentally that the designed CDC SPHs are able to generate full-color autostereoscopic 3D images and video frames very well, without any use of glasses.

- by hwi kim
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- Holography, 3-D Imaging, Spatial Light Modulator, Dispersion Compensation

Fabricating an electrically switchable cylindrical Fresnel lens based on holographic polymer-dispersed liquid crystals (H-PDLC) using a Michelson interferometer is reported. Simplicity of the method and possibility of fabricating different focal length lenses in a single set up are among the advantages of the method. It is demonstrated that the Fresnel structured zone plate acts as a cylindrical lens and focuses light in one dimension. Its electro-optical switching properties are also studied and it is found that at an applied electric field of E=6 Vrms/μm across the sample, focusing property of the sample eliminates with a response of about 1 ms in a reversible manner.

Holograms have been in the public eye for three-quarters of a century, but their influences have deeper cultural roots. No other visual experience is quite like interacting with holograms; no other cultural product melds the technological sublime with magic and optimism in quite the same way. As holograms have evolved, they have left their audiences alternately fascinated, bemused, inspired or indifferent. From expressions of high science to countercultural art to consumer security, holograms have represented modernity, magic and materialism. Their most pervasive impact has been to galvanise hopeful technological dreams. Engineers, artists, hippies and hobbyists have played with, and dreamed about, holograms. This book explores how holograms found a place in distinct cultural settings. It is aimed at readers attracted to pop culture, visual studies and cultural history, scholars concerned with media history, fine art and material studies and, most of all, cross-disciplinary audiences intrigued about how this ubiquitous but still-mysterious visual medium grew up in our midst and became entangled in our culture. This book explores the technical attractions and cultural uses of the hologram, how they were shaped by what came before them, and how they have matured to shape our notional futures. Today, holograms are in our pockets (as identity documents) and in our minds (as gaming fantasies and faux hologram performers). Why aren't they more often in front of our eyes?
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PREFACE
Holograms reached popular consciousness during the 1960s and, over the following decades, evolved along with culture itself. No other visual experience is quite like interacting with holograms; no other cultural product melds the technological sublime with magic and optimism in quite the same way.
Why has its combination of attributes been perennially exhilarating and wondrous? Although the hologram was a product of its times, it was also wrapped in long established cultural threads. Its impacts were conditioned by its antecedents and associations. This protective heritage helped make it impervious to technical disappointments, while ongoing innovation periodically revitalized its spectacular qualities.
This book traces the cultural roots of holograms to explore their influences and effects, assess their counteracting attractions and explain their persistence. It complements and extends my earlier book for Oxford University Press, Holographic Visions: A History of New Science. That volume provided an in-depth account of the creators and concepts behind the subject of holography as a scientific concept, an engineering tool and a business, and was based on extensive archival research and interviews with the originators of the field. Addressing historians of science and technology, holographers and sociologists of expertise, it recounted the trials of creating a new science, a new industry and a new profession from this remarkable concept.
The present book shifts the focus outwards. I turn from the creators of holography to the consumers of holograms in distinct cultural settings. This complementary emphasis enrols fresh audiences, too: readers attracted to visual and cultural studies, scholars concerned with media history, fine art and material studies and, most of all, cross-disciplinary audiences intrigued about how this ubiquitous but still-mysterious visual medium grew up in our midst and became entangled in our culture.

2نقل الصورة من الخيال الي الواقع

- by Sean F Johnston
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- Optics, Science Education, Imaging, Media

Digital halftoning is the process of converting a continuous-tone image into an arrangement of printed and not-printed dots distributed to create an illusion of continuous tone. Traditional halftoning algorithms are inappropriate for lenticular screening where multiple images are columnwise multiplexed into a single image with statistically independent gray levels across neighboring columns. As a means of minimizing intercolumn distortion, we introduce iterative tone correction where gray levels of the spliced image are modified to account for dot overlap. The principal advantage of this new technique is that it preserves the ability to use a traditional, stochastic, halftoning algorithm on the component images prior to spatial multiplexing.

Presentation of the paper selected for the "Virtual Achaeology" conference 2018, S.Petersburg, Russia.

- by Alfonsina Pagano and +2
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- User Experience (UX), Evaluation, Virtual Museums, Holographic Display

This work characterizes holographic polymer dispersed liquid crystals (HPDLC) composite material based on a new monomer, urethane trimethacrylate, by fabricating switchable diffraction grating. The highest diffraction efficiency achieved was 90.3%. Details of the fabrication and preliminary results of electro-optical switching of the HPDLC diffraction gratings are presented and discussed based on the functionality of the monomer. These experimental results are explained by means of morphological scanning electron microscopy analyses.

- by Hossein Jashnsaz
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- Liquid Crystals, Optical Switch, Optical switching, Optics and liquid crystals

Fabrication of an all-optical switchable holographic liquid crystal (LC) Fresnel lens based on azo-dye- doped polymer-dispersed LCs is reported using a Michelson interferometer. It is found that, upon circu- larly polarized photoirradiation, the diffraction efficiency of the fabricated Fresnel lens was increased significantly in a reversible manner. We believe this is due to the anisotropy induced by reorientation of the LC molecules coupled with azo-dye molecule orientation due to trans–cis–trans photoisomeriza- tion, which modulates the refractive index of the LC-rich regions. We also studied the effect of azo dye on the polarization dependency of the fabricated lens.

- by Hossein Jashnsaz
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- Laser, Liquid Crystals, Optical switching, Optics and liquid crystals

An autostereoscopic display system, which allowed multiple viewers simultaneously by use of head-tracking, was previously demonstrated for TV applications in the ATTEST project. However, the requirement for a dynamically addressable, movable backlight presented several problems for the illumination source. In this paper, the authors demonstrate how the use of a novel laser-based holographic projection system can be used to address these problems.

- by Edward Buckley
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- Visual Display Design, Laser, Optical Communication, Autostereoscopic displays