A matrix-addressed liquid crystal display device like LCTV-SLMs is one of the important devices for our electro-holography system. In this system, a CCD camera reads holographic interference fringe pattern and its signal is transferred to the LCTV-SLM by video signal line. The LCTV-SLM works as a dynamic holography device. A spatial filtering technique is applied to remove zero-order diffracted light on reconstruction. A comparison between amplitude-type and phase-type holograms and reconstruction by white light are described. The possibility of fine-pixel LCDs are also discussed.

The generation of dynamic holographic images from an electrically modulated output device poses certain technical problems. Potential solutions to these problems in the form of novel spatial light modulators will be discussed here. The application of semiconductor very large scale integration circuit fabrication techniques to the production of an integrated optic electro- holography output device is presented, including mask generation and electrode pattern production using holographic means.

In the past, the transmission of holograms via television was executed but no holographic TV was realized because there was no suitable recording material. Now a 3-D TV is expected, and recent research on real time holography using a high-resolution liquid crystal device (LCD) is active. In this research we consider the possibility of holographic television and construct the best system possible with commercially available devices. First, holographic fringe patterns for moving objects are made with TV cameras. Then the hologram pattern is transformed to electrical signals and transmitted within the TV frequency band. Finally, the hologram fringe pattern is displayed on the LCD and the 3-D image is reconstructed. In this research, we used the moving object and considered its characteristics. The filtering method was used to improve S/N of the reconstructed image and to extend the viewing angle.

Several methods of increasing the speed and simplicity of the computation of off-axis transmission holograms are presented, with applications to the real-time display of holographic images. A bipolar intensity approach enables a linear summation of interference fringes, a factor of two speed increase, and the elimination of image noise caused by object self- interference. An order of magnitude speed increase is obtained through the use of precomputed look-up tables containing a large array of elemental interference patterns corresponding to point source contributions from each of the possible locations in image space. Results achieved using a data-parallel supercomputer to compute horizontal-parallax- only holographic patterns containing 6 megasamples indicate that an image comprised of 10,000 points with arbitrary brightness (grayscale) can be computed in under one second.

Holographic movies can be seen as a tool to estimate the picture quality of moving holographic images as a step towards holographic television. With this in mind, we have developed an experimental holographic movie system and produced a short duration 3D movie. A number of dolls and moving objects were positioned within a background and illuminated with a He-Ne laser (632.8 nm). Conventional film-making techniques were used during holographic recording to create a more attractive sequence. The techniques included stop-motion, tracking, enhanced depth perception, up-shots, and overlaps. A series of 300 Fresnel type holograms was recorded on standard holographic films. An interesting technical point is that the film was 10 mm high by 200 mm wide. After developing, the films were sandwiched between two rigid acrylic drums (about 1 m in diameter). The drum is rotated and the films illuminated with the He-Ne laser. The display speed can be varied from 6 to 24 frames per second. The films are viewed through a window. Even though this prototype is relatively primitive the resulting holographic movie is quite effective. Several interesting effects were noted. For example, it was found that objects in the movie must not rapidly shift their depth because the human eye cannot track them is they do.

We are developing a prototype of an office holoprinter. We are investigating a new active matrix LCD spatial light modulator in combination with a dry developable photopolymer to be used in our office holoprinter. We will present our latest results in full-color multiple photo generated holograms. These are made using 3 different color laserlines. We will expand on the theory behind the principle recording geometry, to include circular track recording.

As the importance of 3-dimensional information displays in many fields increases, more attention is given to holographic displays. Different kinds of holographic displays are reported in the literature, but the resolution of the available display media is not sufficient to support the extraordinary spatial detail of holograms. In this paper, we propose a new acousto-optical holographic display device which solves significantly the display resolution and the refreshing problems that are common to available holographic displays. The technique is based on the reproduction of the hologram using traveling surface waves. The SAW device that is used as the medium of display has an array of electrodes attached to it. An electrical signal applied to one of these electrodes generates an acoustical wave propagating on the surface of the crystal where the electrodes are the sources. If signals are applied to all of the electrodes simultaneously, propagating waves from the electrodes superpose to form a time-varying surface field pattern on the crystal. This pattern, at a specific time, forms the hologram. The signals which should be applied to the electrodes, in order to have a specified field pattern on the crystal at a specified time instant are found through a mathematical inversion relation. The inversion relationship is derived from the underlying physics. Computer simulations of the proposed TV display show that the proposed system will work as desired. In addition, our preliminary studies show that the proposed system can be constructed with the available acoustical, optical, electronic technology, and with the application of digital signal processing techniques.

An automatic hologram synthesizing system is developed for medical use. The purpose of this system is to synthesize cylindrical holographic stereograms of white light reconstruction for displaying various kinds of medical images such as X-ray, CT, MRI, etc.. To make the use of the system easy and processing rapid, a computer is employed to make the system automatic and to convert original medical images into images suited to hologram synthesis, compact size optical system is designed, and a liquid crystal spatial light modulator is employed as an interface between computer and hologram synthesizer.

Hologram synthesizing machine as a key component of the automatic hologram synthesizer is developed. Hologram synthesizing machine creates cylindrical multiplex holograms with 400 mm diameter from images displayed on liquid crystal SLM or images on 35 mm cine film. The machine consists of a main body, a controller, and a film processing machine, and performs synthesis and chemical processing of hologram automatically within 4 hours. A viewer which reconstructs original images from a synthesized hologram is also developed. In addition to reconstruction of images, the viewer also can point and measure images.

An image processing system for providing original images for synthesizing multiplex holograms is developed. This system reconstructs 3D surface rendering images of internal organs and/or bones of a patient from a series of tomograms such as computed tomography. Image processing includes interpolation, enhancement, extraction of diseased parts, selection of axis of projection, and compensation of distortions. This paper presents the features of this system, along with problems and resolutions encountered in actual test operation at hospitals.

A liquid-crystal (LC) spatial light modulator for hologram synthesis consisting of a high resolution twisted nematic LC-panel of active matrix type has been developed. Output images with signal-to-noise ratio of 30 dB and maximum contrast ratio over 600 were obtained. The stability of the displayed image was analyzed on the basis of two beam interferometry. Confirmation of no appreciable degradation in diffraction efficiency was obtained.

The one-step ultragram, a flexible-format computer-graphic holographic stereogram, is demonstrated in full color. Geometric limitations due to parallel diffusion screen and integral exposure planes are discussed. Image processing and translation schemes that allow for multicolor registration are demonstrated. Emphasis is placed on the pre- and post-swelling color techniques used to register color separated, predistorted component images in order to produce full-color reflection-format stereograms. Experiments using a single laser wavelength to produce a one-step white light-viewable image for each component color are presented. The wide view angle afforded by the flexible ultragram recording geometry, combined with a true color technique, is shown to result in a practical hardcopy display of three-dimensional computer-generated scenes.

We outline an image processing algorithm that can eliminate the spatial, temporal, and spatio- temporal distortions in animated holograms. The impact of using appropriate image processing algorithms on the limits to the size of the viewing zone and the number of separate images that can be stored effectively in a multiplex hologram will also be discussed.

A recording system of one-step Lippmann holographic stereogram with horizontal parallax only is proposed. This system has the capability to be extended to an automatic natural color HS synthesis system by using lasers with different wavelengths. As an initial experiment, monochromatic Lippmann HS is synthesized using a He-Ne laser. A sharp 3D image is reconstructed from the Lippmann HS when it is illuminated with a small white light source. Furthermore, in order to minimize blur of the reconstructed image, an image processing technique is also introduced in this paper.

Solid-propellant rocket fuels frequently have spherical aluminum pellets added to improve combustion efficiency and to improve thrust performance. In order to model the combustion process, information is required about the size of the particles as they lift off of the propellant surface. We have used optical pulsed-laser holography to record an approximate 2.5 cm X 2.5 cm X 2.5 cm volume at the propellant surface in a test rocket motor. A pulsed ruby laser, combined with a laser line filter to remove the flame light, records the hologram. A diffuser is used to remove the phase gradients introduced by the thermal effects in the flame. The scene is reconstructed with a krypton laser, viewed with an optical microscope, and captured on videotape. The recorded scene is digitized and analyzed with digital image processing techniques on a personal computer equipped with a video memory board and an image processing subroutine library. The image processing techniques developed reduce the speckle in the scene, apply a threshold to differentiate the particles from the background, and locate and size the particles. Statistical analysis of the sizing results provides a histogram representation of the particles size distribution. Particle resolution down to 10 micrometers has been achieved with this technique.

There is increasing interest in head-up-displays (HUDs) for automotive use. A number of technologies could be employed for the combiner function including plain glass reflection, dielectric enhancement, and holography. This paper will consider the potential role for conformal holography as the combiner element by initially reviewing the system requirements from an optical design view, how these differ significantly from an avionic HUD, and how they relate to material characteristics and process features. This will involve a consideration in some detail of the effects of specified hologram properties and lamination features on the optical performance and image characteristic of a car HUD. In particular, we shall examine such features as hologram efficiency, bandwidth, tuning position, environmental stability, tolerances, and film lamination effects and how these may influence the key optical characteristics of the image, i.e., distortions, blur, brightness, double imaging (separation and contrast) outside world view, etc.. A theoretical model based on Kogelnik coupled wave theory will be used to illustrate the various tradeoffs between hologram properties and process, image features, and display characteristics (bandwidth, polarization, etc.). This analysis will be related to properties of currently available holographic materials with reference to recent experimental work.

We present experimental results of broadband IR Lippmann holograms. These holograms have bandwidths greater than 350 nm with no harmonic in the visible spectrum.

This paper describes a new tool for experimental mechanics called substrate guided wave (SGW) holo-interferometry. The approach relies on recording and reconstructing time- average, double-exposure, and real-time holograms using light waves guided to the hologram by a dielectric sheet, or substrate waveguide. The study illustrates that SGW holo- interferometry can be used to isolate the reference wavefront from the environment surrounding the hologram, and can be applied to measure the mechanical properties of the substrate itself. These attributes are discussed along with experimental work performed to develop and refine the technique.

An optimal design of a modified type multilevel phase kinoform is presented. Both phase value in each kinoform cell and coordinates of transition points are used as variables of merit function in the optimization of the multilevel phase kinoform. The simulation results show that this multilevel phase kinoform has higher diffraction efficiency and lower relative error than that of others, in which only phase value in each cell is used as variables of merit function during the optimization. Some parameters which affect fabrication of kinoform are also analyzed.

In this paper, we consider the problem of creating holographic sun-protective glasses using reflecting thick-emulsion holograms. Necessary demands for holographic light filters are determined. We research properties of our light filters for different exposure and development conditions.

It was our intention to develop methods for reducing the real image pseudoscopic projection from a laser illuminated pulsed transmission master hologram during the transfer process for the recording of second generation white light viewable reflection copy holograms. The coherence volume of our 10 joule ruby laser is approximately 1.5 cubic meters per pulse, resulting in deep scene holographic recordings of human subjects including props and backdrops. The vibration isolation optical bench used in our lab for the transfer process is only 4 X 8 feet which limits the size of the holograms produced to 32 X 43 cm or smaller. Much of the information contained in our master holograms fell outside the boundaries of medium format holographic film or plates, usually limiting holograms of live subjects to head and shoulder portraits. The introduction of a plano-convex lens between the master and the copy hologram in a typical reflection hologram recording configuration reduced the size of the real image projected from the master onto the copy hologram, allowing us to record full figure compositions on film as small as 4 X 5 inches. The size and focal lengths of the various lenses used, the recording geometries, and the developing chemistry used to achieve acceptable skin tones are discussed and illustrated.

The first step in the construction of a very deep, large source size, white light illuminated hologram is discussed. We outline the steps taken thus far in the creation of our computer- generated master hologram slit. Our goal is to computer generate a 2 meter master slit for optical transfer via Benton rainbow holography technique. The transfer hologram will ultimately be re-illuminated by the moon and fill a space of approximately 8000 cubic meters. Discussion of the relative merits of synthetic stereographic methods and CGH methods is presented as well as several novel hybrid techniques. The CGH test prints thus far created are evaluated for several types of aberrations and methods of pre-distortion and distortion correction are proposed.

We present true-color holographic stereograms made using multiple layers of Du Pont OmniDex photopolymer. Red, green, and blue color separations are reproduced at optimum replay wavelengths by exposing in blue and post-swelling using monomer color tuning films. This material is also used to record pseudo-color and true-color holograms of real-life scenes. A theoretical analysis of the color-reproduction is applied to the technique being presented and compared to results using other materials. The signal-to-noise ratio, color rendering, and color gamut area properties are shown to be comparable to those found when using dichromated gelatin and considerably better than holograms recorded in silver halide materials.

The light-harvesting protein in the purple membrane of halobacterium halobium, called bacteria rhodopsin, has been proposed as an erasable holographic storage medium. It has demonstrated erase times on the order of psecs, with a natural reset time of msecs. It has been shown capable of storing both amplitude and phase holograms, or a combination thereof, with diffraction efficiencies on the order of 7%. While this is lower than in some silver halide applications, other properties, such as shelf life and resolution, are outstanding compared to conventional methods. There are many holographic applications of bacteria rhodopsin (bR), but by far one of the most interesting is its potential use in high speed interferometry. Theoretically, bR could act as a temporary recording material for storing interferograms which could then be transferred permanently to a computer via a CCD array. This would greatly increase both the speed and resolution of interferometric technology, and allow for the recording of interferometric 'movies', which is impossible using current holographic recording materials. This and other applications of bR will be discussed, along with its material chemistry and state of technology.

The monomer state methylene blue (MB) dye plays a major role as a sensitizer in methylene blue sensitized dichromated gelatin (MBDCG). The dimer state of the MB can be reduced significantly by controlling the concentration of the MB, the chromium and the water in the gelatin. The authors achieved over 80% transmittance of the MBDCG plate for red light without sacrificing the sensitivity. Some experimental results of full color holograms recorded by the single beam Lippmann method (Denisyuk configuration) are presented.

Based on the conventional one-step true color rainbow holography, a new true color rainbow holography of 3-D diffused object is presented. By means of conjugate reconstruction with one wavelength laser, the hologram can be recorded in only one type of recording material with single exposure to achieve true color rainbow hologram. Therefore, a photoresist master can be produced for embossing copy.

In this paper, the new contouring method based on the use of an absorptive medium is presented. Theoretical calculation shows that the conventional immersion mapping method can be modified for analysis of object form on one interferogram. In the experiment, we obtain a contour map of wedge-like surface. The absorptive medium was aqueous solution of dye, which has an absorptive line in the range of He-Ne laser irradiation. Water is the second immersion medium. The contour map of the object has fringe visibility changing with the object depth, due to absorption of the first medium.

A new kind of rainbow holography called real image astigmatic rainbow holography is presented. Differing from the conventional astigmatic rainbow holography which is deeply imaged behind the hologram , this new hologram can project out a real image distinctly in front of the hologram , therefore, making the display more fantastic and attractive.

The MIT holographic video display can be converted to color by illuminating the 3 acoustic channels of the acousto-optic modulator (AOM) with laser light corresponding to the red, green, and blue parts of the visible spectrum. The wavelengths selected are 633 nm (red), 532 nm (green), and 442 nm (blue). Since the AOM is operated in the Bragg regime, each wavelength is diffracted over a different angular range, resulting in a final image in which the three color primaries do not overlap. This situation can be corrected by shifting the diffracted spatial frequencies with an holographic optical element (HOE). This HOE consisting of a single grating is placed right after the AOM in the optical setup. Calculation of the required spatial frequency for the HOE must take into account the optical activity of the TeO2 crystal used in the AOM. The HOE introduces distortions in the final image, but these are so small as to be visually negligible. The final images are of a good quality and exhibit excellent color registration. The horizontal view zone, however, diminishes for the shorter wavelengths.

This paper describes a holography camera for making many art treasures into holograms, cineholography, and holographic television (real-time electro holography).

The mechanisms of print-out in silver halide holograms are outlined and proposed methods for minimizing print-out are reviewed and discussed. Bleached holograms (transmission and reflection) were subjected to an artificial daylight source (765 W/m2 in the waveband 270 - 800 nm), for periods of time up to 15 hours. Three commonly used bleach processes were investigated for transmission holograms (rehalogenating with and without fixation, and a reversal bleach) together with some post-bleach treatments. Reflection holograms were bleached in parabenzoquinone (PBQ) solutions. A number of post-bleach (anti-print-out) treatments were investigated but none were ideal. However, a slow increase in transmission of the holograms, on dark storage, after the final print-out exposure ('print-out relaxation') was observed and rebleaching of holograms, after print-out, made them more resistant to further print-out. The influences of a multiplicity of processes on print-out and its relaxation are discussed and recommendations made for combatting the effects of print-out in bleached holograms.

Dichromated gelatin exhibits variable changes in effective refractive index (n) from 1.54 before exposure to less than 1.25 as it expands during processing. This aerogel like effects causes aberrations in diffractive optics and Kogelnik's theory predicts strong polarization separation in gratings at many different angles other than 90 degrees. The diffraction efficiency of both S and P polarizations at any angle is dependent on the product of thickness and index modulation while the angle inside the medium is dependent on n. We investigated predicted conditions where only one polarization would be diffracted and subsequently proved n varies from about 1.4 to 1.2 after processing and depends on the film thickness and processing procedures. Transmission gratings made at angles from 36 to 66 degrees were fit to mathematical models as proof of the phenomena, some performed with extinction ratios greater than 100:1. We were also able to demonstrate a similar range in conformal reflection structures and to design a novel polarizer. The calculation of exposure geometries for display holograms becomes more accurate when index change is included in the formulas but some results remain hard to explain.

Since a hologram can simultaneously scan and focus a laser beam, we have investigated the use of a holographic line scanner in laser printers. However, conventional holographic scanners, suffer from wavelength shifts of laser diodes. To prevent problems caused by wavelength shifts, a conventional holographic scanner needs an expensive thermal controller for a laser diode or a frequency-stabilized laser diode. To achieve a low cost scanner, we proposed a new holographic scanner using a holoplate that compensates for large wavelength shifts. In this paper, we will discuss the wavelength shift compensation of a new scanner.

Directionality in a holographic screen may be useful for projecting images to be seen in complete horizontal parallax. The continuous sequence of views from an object may be transferred from the object and enlarged at the screen, giving the same appearance of a holographic image. Due to the actual movement of the object, images in four dimensions may now be produced with a projector whose spatial dimensions are much smaller than those of the screen. One technique that allows for this result is the chromatic encoding of views by means of holographic optical elements. This is demonstrated to be a complete reproduction of the original light distribution, although its spectral continuous distribution of colors makes each view monochromatic, not allowing for good color reproduction. The resulting system may substitute conventional holography in some visual applications if registering is not necessary but only the effect of the phantasmagoric image. Furthermore, it allows for the enlarging of holographic images, performing also the direct conversion of the image of a conventional off- axis hologram to a white-light image.

Thus far, network modules have mostly been implemented on computers and electronic hardware with low density interconnections at low speed. Optics potentially offers high density parallel interconnections at high speed. However, the implementation has been limited to single layer machines. As a result, no practical implementation has yet been reported. The lack of suitable materials providing dense synaptic interconnections is the primary reason for the slow progress in the practicality of optical neural network implementation. Photorefractives are considered as suitable materials. However, photorefractives have inherent problems including scattering, sensitivity, low refractive index modulation and fast decay. Furthermore, optical network systems based on photorefractives have low signal-to-noise ratio, have poor stability, and cannot realize error driven learning algorithms, such as the back error propagation. In addition, low diffraction efficiency severely affects cascadability of neural layers. Therefore, multilayer machines using photorefractive crystals are difficult to implement. Physical Optics Corporation (POC) has developed a new dynamic birefringent material for recording polarization holograms with selective enhancement or erasure in real time. Extensive investigation has shown that POC's material offers well-controlled dynamic behavior that is superior to photorefractive crystals, Polaroid DMP-128, Du Pont photopolymer and Kodak's silver halide for neural network interconnection applications.

A holographic device has been developed that greatly improves the efficiency of solar energy conversion. The single-element hologram focuses light to the side and also spectrally splits it. The output appears as a thin concentrated line, focused perpendicular to the hologram and displaced to the side. Different wavelengths are diffracted, concentrated, and dispersed to different locations on the line which resembles an elegant rainbow in the visible. The hologram lets each of two or more different solar cells absorb only those wavelengths which can efficiently convert to electric power. The device also prevents overheating by diffracting unwanted infrared radiation away from the cells. The side focus eliminates shadow effects, and cooling is easy, since the cells are not cascaded and the heat load is minimal. This novel system is ideal for concentrated, split-spectrum, high efficiency solar power generation.