This PDF file contains the front matter associated with SPIE Proceedings Volume 7619, including the Title Page, Copyright information, Table of Contents, and the Conference Committee listing.

A frameless hologram display module employing a modified resolution redistribution system is proposed. The frameless display modules can be aligned two-dimensionally so as to realize a large screen size. The modified resolution redistribution system is constructed by the combination of a one-lens imaging system and a lens placed on the image plane to achieve a frameless display screen. By making the magnification of the one-lens imaging system larger than unity, the screen size can be made larger than the imaging lens. The prototype module was constructed using a spatial light modulator with a resolution of 1,980×1,080 and with a pixel pitch of 8.0 μm. The horizontal resolution increased by four times and the magnification of the imaging system was 2.88. The horizontal resolution was increased to 7,920 and the horizontal pixel pitch was reduced to 5.8 μm. The screen size of the module was 2.0 inches and the horizontal viewing zone angle was 6.3°.

Image-based holographic stereogram rendering methods for holographic video have the attractive properties of moderate computational cost and correct handling of occlusions and translucent objects. These methods are also subject to the criticism that (like other stereograms) they do not present accommodation cues consistent with vergence cues and thus do not make use of one of the significant potential advantages of holographic displays. We present an algorithm for the Diffraction Specific Coherent Panoramagram -- a multi-view holographic stereogram with correct accommodation cues, smooth motion parallax, and visually defined centers of parallax. The algorithm is designed to take advantage of parallel and vector processing in off-the-shelf graphics cards using OpenGL with Cg vertex and fragment shaders. We introduce wavefront elements - "wafels" - as a progression of picture element "pixels", directional element "direls", and holographic element "hogels". Wafel apertures emit controllable intensities of light in controllable directions with controllable centers of curvature, providing accommodation cues in addition to disparity and parallax cues. Based on simultaneously captured scene depth information, sets of directed variable wavefronts are created using nonlinear chirps, which allow coherent diffraction of the beam across multiple wafels. We describe an implementation of this algorithm using a commodity graphics card for interactive display on our Mark II holographic video display.

We present a novel method for single frame particle image velocimetry of micron scale spheres based on holographic video microscopy. Our approach takes advantage of the blurring that recorded holograms suffer when a sphere moves during the exposure period of the camera. By measuring the angular variance in intensity of the blurred hologram, we extract a modelindependent metric for the particle velocity. We find this to be accurate for speeds that permit characterization of other properties of the sphere, such as radius and refractive index through Lorenz-Mie mocroscopy. Singl-frame holographic velocimetry yields information on the dynamics of a particle, without sacrificing any other measurements.

The video stream captured by an in-line holographic microscope can be analyzed on a frame-by-frame basis to track individual colloidal particles' three-dimensional motions with nanometer resolution, and simultaneously to measure their sizes and refractive indexes. An efficient particle-tracking algorithm automates initial position estimation with sufficient accuracy to enable unattended holographic particle tracking and characterization. In this work, we demonstrated this approach to flow visualization in a microfluidic channel and also to flow cytometry of micrometer-scale colloidal spheres.

We are studying electronic holography and have developed a real-time color holography system for live scene which includes three functional blocks, capture block, processing block, and display block. In this paper, we will introduce our developed system after describing basic idea that quickly calculates hologram from IP image. The first block, capture block, uses integral photography (IP) technology to capture color 3-D objects under natural light in real time. The second block, processing block, consists of four general personal computers to generate holograms from IP images in real time. Three half-zone-plated holograms for red, green and blue (RGB) channels are generated for all captured IP images by using fast Fourier Transform. The last block, display block, mainly consists of three liquid crystal displays to display the holograms and three laser sources for RGB to reconstruct the color 3-D objects. All blocks work in real time, i.e., in 30 color frames per second.

Single-shot digital holography is developed for instantaneous recording of the complex-amplitude inline hologram by applying spatial heterodyne modulation and spatial frequency filtering. The complex-amplitude in-line hologram can be precisely extracted from one off-axis hologram for the reference light beam with general spatial phase distribution. Bandwidth of the complex-amplitude hologram is enlarged up to a half of the spatial sampling frequency by eliminating the zero-order term from the off-axis hologram, which is a theoretical upper limit in the single-shot recording. Experimental results show that fine images are reconstructed from the complex-amplitude hologram as a result of elimination of the direct light beam and the conjugate beam.

Phase-shifting digital holography based on the spatial carrier interferometry makes available for snap-shot recording and reconstruction of three-dimensional objects in dynamic motion without erroneous signals. Key point of the method is an introduction of tilt in the reference plane wave in recording a hologram so that relative phase difference between sequential pixels of image sensors becomes 2π/3 or π/2. This requires theoretically rigorous alignment in the angle of incidence of the reference wave, and therefore, it seems to make the method impractical. In the present paper, the tolerance of the incident angle of the plane reference wave in the method is analyzed theoretically and verified by computer simulations. It is found from these studies that the rigorous alignment of the incident angle of the plane reference wave is very important requirement to reconstruct the correct complex amplitude of the object wave. However, it is also found that in the case of miss-alignment, we can derive the correct object waveform by compensating the linear phase due to miss-alignment.

Computer-generated hologram (CGH) is a one of 3-D display technologies, and it reconstructs natural and virtual objects. However, improvement of the reality of reconstructed images is necessary for reconstructing complex and clear scenes like computer graphics. We have studied about the rendering techniques for CGH, and proposed the method considering background reflections and reflectance distributions. The background reflections and reflectance distributions are the characteristics of reflection. Metallic objects and reflected scenes were reconstructed by considering these. In this paper, we improved the previous works for express complex scenes. The proposed method considered the background reflections and reflectance distributions on the curved surface such as convex and concave mirrors. By using the phase transformation, the background reflections and reflectance distributions on it with some roughness are generated. We performed that the background reflections and reflectance distributions on the convex and concave mirrors with roughness are actually obtained through computational and optical reconstructions.

In this paper, we propose a new algorism for calculating computer-generated hologram (CGH) for 3D image display. The wavefront is calculated from light-ray information, which can be obtained by artificial computer graphics or imagebased renderings using the data captured by a camera array. The view interpolation, hidden surface removal, and gloss reproduction are easily implemented by utilizing the techniques of image-based rendering or light-field rendering. The method is similar to the CGH based on the principle of Holographic Stereogram (HS), but using HS based CGH, the image far from the hologram plane is blurred due to the light-ray sampling and the diffraction at the hologram surface, so it is not suitable for the display of deep scene. Thus we proposed the use of virtual "Ray-Sampling (RS) plane" near the object, and the wavefront at the RS plane is calculated from the light-rays. The wavefront propagation is then simulated based on Fresnel diffraction from the RS plane to the hologram. The hologram pattern is obtained from the complex amplitude distribution on the hologram plane. Even if the RS plane is distant from the hologram, the resolution of the reconstructed image is not degraded since the long distance light propagation is calculated by diffraction theory. In the experiment, we obtained high resolution, deep 3D image with gloss appearance with using the image data generated by commercial rendering software.

A new method is developed for recording and reconstructing a microscopic high-resolution 3-D image with large depth. Any imaging lens is not located between the object and the CCD in our optical system. A number of partial off-axis holograms are sequentially recorded with one CCD, or are recorded at once with multi-channel CCD by the single- shot digital holography. Partial complex-amplitude in-line holograms are extracted from recorded off-axis holograms by applying the simple-shot digital holography, and are arranged in order to generate a wide complex-amplitude in-line hologram. A high-resolution image with no distortion is numerically reconstructed from the wide complex-amplitude inline hologram.

Packaging of electronic and photonic components requires high accuracy, which has to be preserved not only in the process of manufacturing, but also in the process of operation. Therefore, products that are built using microelectronic components are subjected to extensive reliability testing. Shifts in alignment, both linear and rotational, could occur with time or simply because of the temperature variations and the associated expansion/contraction of the materials. Identifying where these problems occur and obtaining quantitative results with sub-micron accuracy could potentially be achieved by photometric measurements. Unfortunately, many conventional techniques are virtually useless when measurements are performed on diffuse objects, such as photonic packages. These limitations can be avoided using holography, which facilitates recording and reconstruction of the optical waves reflected from any surface. In the process of reconstruction it is possible to reproduce not only the amplitude of the reflected wave, but also its phase distribution, which carries information about the distance to each point illuminated with light. An optical technique developed by our group and presented in this paper is based on holographic interferometry. The main goal is to make this technique suitable for reliability testing, which provides vital information for modifications in the design or the packaging process.

We report a new method to detect coherence waves by using photoconductivity in semi-insulating semiconductors. The method is based on a low coherence interferometry that uses a superluminescence light emission diode as the light source. In a two-wave mixing configuration, a photorefractive multiple quantum wells (PRQW) device serves as the beam combiner. When the signal beam and the reference beam interfere in the PRQW, it forms an intensity fringe pattern along the device surface. In a transverse geometry of the PRQW, photocarriers in the bright region of the intensity fringe move to the dark region. The space charge distribution causes changes of local electric field in the PRQW. It leads to the changes in absorption and index of refraction as well as photoconductivity. Conventional coherence domain imaging using PRQW is based on the diffraction of one of the beams in multi-wave mixing, such as two-wave mixing and four-wave mixing. Our innovation is to use the photoconductivity to detect coherent signals. We tested the concept by changing the optical delay and measuring the photocurrent. The change of the local electric field causes the change of the photocurrent in PRQW even when the totally incident light density stays the same. We studied the photocurrent under various externally applied electric fields and incident light densities. The relative change of photocurrent is about 10 times higher than the relative change of diffraction in two-wave mixing, which is the highest diffraction efficiency in multi-wave mixing configurations. The change of photocurrent is also proportional to the incident signal light density while the reference intensity keeps the same and the total intensity is relatively low. This method provides a potential solution of coherent signal detection using PRQW for biomedical optical imaging applications.

Active interferometers can continuously adapt themselves to the change of measuring conditions and environment. This type of interferometers is investigated in the article. As a major feature, the wave fronts of the interferometer are formed by different holographic optical elements. Using this technique the fringe density at highly deformed points can be decreased or different components of the complicated fringe pattern can be removed which results in increase of the sensitivity and leads to easier evaluation of the fringe pattern. Selected applications in speckle metrology and digital holography are shown demonstrating applications of computer generated and classical types of HOE-s.

Zonal wavefront sensors of the Shack-Hartmann type have dynamic range and spatial resolution which are determined by the micro lens diameter and focal length. Increase in the spatial resolution requires reduction in the aperture size of each micro lens which effects the dynamic range. This paper presents a zonal wavefront sensing scheme based on an array of gratings that can provide programmable control over both the spatial resolution and the dynamic range. In the proposed scheme the outline of the photodetector array can be independent of the outline of the incident beam whose wavefront is to be measured. In this paper the scheme is implemented using a twisted nematic liquid crystal spatial light modulator.

In recent years the developments in computer technology have drastically accelerated. In order to handle the ever growing amount of data to be stored, an increase in the storage capacities of mass storage media is necessary. A promising approach is holography, where the storage capacity is greatly increased by using the entire volume instead of only the surface of the medium. Write-once media, which are mainly based on photopolymer systems, seem to be fairly advanced. For a rewriteable media, only few systems can meet the strict requirements for holographic data storage materials. Photoaddressable azobenzene-based polymer systems are the most promising candidates, however the photo-physical sensitivity of these materials has to be further increased. Low molecular-weight organic glasses with azobenzene moieties can also be used for reversible inscription of holographic volume gratings. They exhibit a faster response time than a comparable photoaddressable polymer due to a lack of chain entanglements. A new photochromic molecular glass with optimized physical and photo-physical properties is investigated as blending materials to improve the photochromic response of photoaddressable polymers. By doping this photochromic molecular glass into photoaddressable polymers we are able to combine the high stability of polymer systems with the fast response of molecular glasses, thus creating a system which has the advantages of both material classes.

We have been developing a new class of recording materials for volume holography, offering the advantages for full color recording and depth tuning without any chemical or thermal processing, combined with low shrinkage and detuning. These photopolymers are based on the two chemistry concept in which the writing chemistry is dissolved in a preformed polymeric network. This network gives the necessary mechanical stability to the material prior to recording. In this paper we show that the recording process in these materials can be successfully described within a reactiondiffusion model. For the first time the combination of plane-wave recording data in transmission and reflection geometry was used to extract the model parameters. This was achieved via a master curve construction of the respective power density response functions of the photopolymer at saturation recording conditions. Within that model, power density response, spatial frequency response, non-locality effects, beam ratio effects and even dosage response can be predicted and explained for a wide range of CW recording conditions which are important for various holographic applications of these new materials.

Here we describe a new holographic recording method in which a separate reference wave is not required. Object wave is split into two beams and one of them is spatially filtered to create a plane reference wave. This method allows the use of low coherence light sources since pathlengths of the interfering waves are matched automatically which will lead to holographic recording of objects at any distance rather easily. Optical setup will be discussed and the experimental results will be presented.

The very first demonstration of our refreshable holographic display based on photorefractive polymer was published in Nature early 2008¹. Based on the unique properties of a new organic photorefractive material and the holographic stereography technique, this display addressed a gap between large static holograms printed in permanent media (photopolymers) and small real time holographic systems like the MIT holovideo. Applications range from medical imaging to refreshable maps and advertisement. Here we are presenting several technical solutions for improving the performance parameters of the initial display from an optical point of view. Full color holograms can be generated thanks to angular multiplexing, the recording time can be reduced from minutes to seconds with a pulsed laser, and full parallax hologram can be recorded in a reasonable time thanks to parallel writing. We also discuss the future of such a display and the possibility of video rate.

We present a set of analytical formula on describing the diffraction field of the three dimensional (3D) triangular-meshbased model. The advantage of the proposed method is that it can avoid using the numerical algorithm -- Fast Fourier Transform, which leads to a depth-of-field limitation by the Whittaker-Shannon sampling theorem. We employ the proposed method to generate the hologram of 3D texture model derived from the real scene or 3D design software. In order to further increase the computation speed, we have rendered a real scene by employing the GPU platform. Our homemade GPU algorithm performs hundreds of times faster than those of CPU. As we developed a general phase adjustment technique for polygon-based algorithm, the holographic reconstructed scenes possess high performance.

We have found a way to use movies made by mobile phones video cameras as the source of information needed for digital holographic printing. Actually, in order to print digital hologram, one needs to have a sequence of images of the same scene taken from different angles and nowadays video cameras incorporated into mobile phones can be an acceptable source of such image sequence. In this article we are describing this holographic imaging process in details.

In this paper, we have investigated the floating image display with the computer-generated hologram (CGH). As the 3D display, the floating 3D image gives strong dimensional impression to the viewer. However, there are few reports about the floating image display by the CGH. Since the required spatial frequency to the display is very high compared with the non-floating image display, it is difficult to output the CGH that displays the floating image. If the CGH is output by the inadequate device, the viewing area and the image size of the CGH is not suitable for practical use. Therefore, to reduce the required spatial frequency for the fringe pattern of the CGH, the position of the object is placed at the behind of the hologram plane. Also, the huge calculation amount of the fringe pattern is big problem. In our resent work, since we have developed our output device (named fringe printer) for the fringe pattern, the pixel pitch of the printed fringe pattern is improved from 0.87 μm to 0.44 μm. By using the fringe printer, we have achieved to write over 100 Gpixel hologram. Therefore, we investigate to make the floating image display with the fringe printer. To realize the wider and larger image display, the image is reconstructed by the conjugate of the original reference wave to reproduce the real image. Also, to solve the huge calculation amount, we employ the graphics processing unit to make calculation faster.

In this paper, we use multi-point source illumination to enhance the resolution of digital holographic microscopy without shifting the CCD camera. The specimen is illuminated from many directions by using multi-point sources which are easily created by a lens-array. The high frequency information of the specimen can be captured at a fixed position of CCD camera. All information is then synthesized to increase the resolution.

We analyze the electromagnetic wave scattering problem from multilayer-coated Fourier grating for a general angle of incidence and arbitrary polarization. This analysis is treated in quasi-two-dimensional problem with the scalar wave function where the incident wave vector is not perpendicular to the ruling direction of the gratings. The analytically procedure is applied to T-matrix method with R-matrix propagation algorithm. This formulation can be calculated in the closed-form expressions because R-matrix propagation algorithm is used avoiding a singularity in matrix elements for the evanescent mode. Numerical examples are also presented for diffraction efficiencies versus incident and azimuth angle.

In this paper, we demonstrate the application of the spiral phase filter for image enhancement in phase shifting digital holographic microscopy system. The method is based on Fourier plane filtering of the microscopic image with a spiral phase filter which is located at a computer controlled Spatial Light Modulator (SLM) in the optical imaging pathway of phase shift digital holographic microscopy system. Spiral phase filter is designed by radial isotropic Hilbert transform. The spiral phase filter as a spatial filter in Fourier plane of an imaging setup has been proposed as an isotropic edge detection method providing strong contrast enhancement of microscopic amplitude and phase objects. Since all threedimensional information is captured by phase shifting digital holographic microscopy, the reconstructed phase object or cell is reconstructed clearly observed in three-dimension.

We present the behaviors in the time of the diffraction efficiency of holographic gratings, there were recorded in two monosaccharides, glucose and fructose, and both were sensitized with potassium dichromate and blue dye. There monosaccharides present diffraction efficiency with a maximum of 7% approximately, without protection, the sample exposure at environmental conditions, after 48 hours the parameter of diffraction efficiency decays. By this reason is necessary to protect after of the stabilized emulsion the hologram.

The study was carried out during real time holographic gratings formation when the coating emulsions age as a function from the time. The experiments are studied by influence of hologram parameters to get the diffraction efficiency at room conditions through changes of electrical potential application and pH dependence on coating solutions for hologram recording process.

Transmission of hologram is very important to realizing the holographic 3D TV. Transmission of Computer Generated Hologram(CGH) data using SSTV wire-less method is tried before and one frame with 76.8k bit data is transmitted by 2kbbs is reported1). In this research we consider to more high speed transmission and more high resolution hologram data transmission using white LED.

Holographic data storage (HDS) is a prospective, next-generation mass optical storage system. In HDS, wave-front aberration in the optical system causes deterioration of the reconstructed signal quality. In this study, to clarify the margin allowed for HDS drive development, the influence of aberration in the case of wave-front aberration of defocus, where the influence of image degradation is especially high, was measured in the optical system. Further, with the aim to improve the error rate, a finite impulse response (FIR) filter using LMMSE was applied to the image deteriorated by the wave-front aberration. Consequently, we confirmed that the error rate can be reduced by applying the FIR filter for each modulation code.

Computer generated holograms are expected to be an ideal three-dimensional display system. Enormous computation time, however, is required to calculate holograms. There are fast calculation methods based on fast Fourier transforms using a patch model, but they require two-dimensional fast Fourier transforms for each patch. Therefore, calculating the object light from a complex object that has many patches takes much computation time. We propose a fast calculation method using pre-calculated object light without the fast Fourier transform and show the results of our method. Our method calculates object lights from complex objects including large-angle tilted patches using only one cylindrical pre-calculated object light. The memory needed for pre-calculated object light is smaller than the previously proposed method.

Holography is considered as an ideal 3D display method. We generated a hologram under white light. The infrared depth camera, which we used, captures the depth information as well as color video of the scene in 20mm of accuracy at 2m of object distance. In this research, we developed a software converter to convert the HD resolution depth map to the hologram. In this conversion method, each elemental diffraction pattern on a hologram plane was calculated beforehand according to the object distance and the maximum diffraction angle determined by the reconstruction SLM device (high resolution LCOS). The reconstructed 3D image was observed.

Computer generated holograms (CGHs) require high resolution output devices. However, resolutions of current LCDs are not high enough for practical use. This causes a narrow visual field and viewing zone, conjugate images, ghost images, and 0th-order light which hinder our view. We propose a method for solving these problems. Moreover, the enlargements of the visual field were realized by changing the distance of reconstruction light source. However, the shapes of 3-D objects were distorted using this method. We have solved the problem by correcting CGH data and confirmed the effectiveness of our method in the optical experiments.

Recently, N-LUT method to dramatically reduce the number of pre-calculated interference patterns required for generation of digital holograms was proposed. In this method, the fringe patterns for other object points on each image plane can be obtained by simply shifting this pre-calculated PFP according to the displaced location values from the center to those points and adding them together. Accordingly, CGH pattern for arbitrary line is shifted with amount of discretization step for the direction of next line, same images for arbitrary line are generated in the next line. And then differences between two lines are occurred, these differences are compensated in CGH pattern using the N-LUT method. Accordingly, in this paper, a new approach for fast computation of CGH patterns for the 3-D image by taking into account of the line-redundancy between lines of the 3-D image is proposed. Some experiments with a test 3-D object are carried out and the results are compared to those of the conventional methods. Accordingly, in this paper, a new approach for fast computation of CGH patterns for the 3-D image by taking into account of the line-redundancy between lines of the 3-D image is proposed. Some experiments with a test 3-D object are carried out and the results are compared to those of the conventional methods.

American Sign Language (ASL) is one of the languages giving the greatest help for communication of the hearing impaired person. Current 2-D broadcasting, 2-D movies are used the ASL to give some information, help understand the situation of the scene and translate the foreign language. These ASL will not be disappeared in future three-dimensional (3-D) broadcasting or 3-D movies because the usefulness of the ASL. On the other hands, some approaches for generation of CGH patterns have been suggested like the ray-tracing method and look-up table (LUT) method. However, these methods have some drawbacks that needs much time or needs huge memory size for look-up table. Recently, a novel LUT (N-LUT) method for fast generation of CGH patterns of 3-D objects with a dramatically reduced LUT without the loss of computational speed was proposed. Therefore, we proposed the method to efficiently generate the holographic ASL in holographic 3DTV or 3-D movies using look-up table method. The proposed method is largely consisted of five steps: construction of the LUT for each ASL images, extraction of characters in scripts or situation, call the fringe patterns for characters in the LUT for each ASL, composition of hologram pattern for 3-D video and hologram pattern for ASL and reconstruct the holographic 3D video with ASL. Some simulation results confirmed the feasibility of the proposed method in efficient generation of CGH patterns for ASL.

A large-scale CGH named "The Venus", created by using the polygon-based method, was demonstrated in the last year. However, the 3D scene of the Venus is restricted by the shifted Fresnel method used for numerical propagation using segmented frame buffers, because severe aliasing errors are produced if the propagation distance is shorter than a specific value in the method. In this paper, a novel method referred to as the shifted angular spectrum method is proposed for short distance propagation using the segmented frame buffers. The method can remove the restriction and give flexibility to design of 3D scenes. Both CGHs calculated by old and new methods are demonstrated.