This PDF file contains the front matter associated with SPIE Proceedings Volume 6488, including the Title Page, Copyright information, Table of Contents, Introduction (if any), and the Conference Committee listing.

Multitudes of materials were and are investigated for holographic recording. materials and processes are advantageous because its has high exposure sensitivity, high diffraction efficiency, stability, etc. We report a photosensitive emulsion its electro-optical and chemical properties by mixing PVA with metallic salts and ammonium dichromate. We describe a hypothesis with respect to some mechanisms of photo and thermo sensitivity to different characteristics in emulsions.

A Polyelectrolyte can be used as replayed recording holographic medium with high diffraction efficiency by applied conventional lithography techniques and heating, the main characteristics from this material are non-toxic, soluble-water, others advantages are in production time and unit cost to replica holograms.

We developed a holographic material based on glucose. The material is recorded by its crystalline polymerization when it is radiated with ultraviolet light. Also we doped our holographic material with a colorant (pink Deiman^(R)), obtaining a parallel photoluminescence phenomenon. Thus, a diffraction grating generated in a computer is transferred to our material using UV light, and it is reconstructed by a green laser beam. We analyzed the grating efficiency and the photoluminescent light emitted.

Photopolymer films containing epoxy monomers were explored for holographic recording. A photopolymer film composition was optimized by using a s-triazine epoxy monomer and coated on a glass substrate. The film showed high sensitivity to visible light, to lead polymerization as determined by a photo DSC. The diffraction efficiency of the photopolymer film was determined as 61%, which was stable for longer than 1 week. A holographic screw image could be recorded onto the photopolymer film. The image was stable when read by a visible light.

Holographic pulsed light induced recording in azobenzene polymers is being extensively studied due to its potential use in optical storage applications. In this communication we show our studies in the formation of holographic grating recording in different azobenzene side chain polymethacrylates irradiating with a single 4 ns light pulse at 532 nm. Holographic gratings have been registered using intensity and polarization patterns. The time response and stability of this diffraction efficiency have been studied as a function of the recording energy. Stable values of the diffraction efficiency have been obtained in some of the polymers after one single pulse of several tenths of mJ/cm². We have also estimated the relevance of surface and phase contributions at different recording energy regimes. Polarization holographic gratings with efficiencies of about 0.8% (measured at 632.8 nm) have been registered with no measurable relief contribution.

Interference microscopy was applied to direct microscopic observation of temporal evolution of phase holograms in LiNbO₃:Fe photorefractive crystals. First a hologram was recorded in the sample, and diffraction efficiency was monitored during hologram build-up using inactinic laser light. Thus kinetics of hologram build-up could be determined. The initial hologram was erased using white light. Then a series of write-erase cycles were performed with increasing exposure times. Holograms were observed by interference microscope after each exposure. The time elapsed between the exposure and the microscopic observation was negligible compared to the relaxation time of the hologram. The obtained temporal evolution of grating profile gives a deeper insight into the physical mechanism of hologram formation in photorefractive materials than simple diffraction efficiency measurements. A congruently grown sample of LiNbO3 doped with 10-3 mol/mol Fe in melting was studied by the method above. Sample thickness was set to 300 &mgr;m to allow correct microscopic observation. Plane-wave holograms were recorded in the samples using an Ar-ion laser at &lgr; = 514 nm of grating constants of 3, 6.5 and 8.8&mgr;m.

Bragg detuning effect and asymmetry of diffraction efficiency are serious problems if a photopolymer is used for the recording material of holographic storage. The critical reasons are bulk refractive index change and shrinkage of the recording materials. Until now, analyzing these effects bas been based on the K-sphere and the transmission hologram only or the reflection hologram only. A modified numerical model has been established explaining both holograms together and its results are well matched with experimental results. Bulk refractive index change causes + directional angle detuning on the transmission and reflection holograms. Material shrinkage leads to + directional angle detuning on the transmission hologram, but - directional angle detuning on the reflection hologram. The measured data are matched with Bragg detuning effect on the transmission and the reflection holograms with the proper the bulk refractive index change and shrinkage ratio of the material. For the asymmetry of diffraction efficiency, attenuated grating of material has also been considered. And asymmetries are reproduced on both holograms using absorption coefficient of attenuated grating.

We have made attempts to measure directly the small-scale variation of optical path lengths in photopolymer samples. For those with uniform thickness, the measured quantity is supposed to be proportional to the refractive index of the photopolymer. The system is based on a Mach-Zehnder interferometer using phase-locking technique and measures the change in optical path length during the sample is scanned across the optical axis. The spatial resolution is estimated to be 2&mgr;m, which is limited by the sample thickness. The path length resolution is estimated to be 6nm, which corresponds to the change in refractive index less than 10^-3 for the sample of 10&mgr;m thick. The measurement results showed clearly that the refractive index of photopolymer is not simply proportional to the exposure energy, contrary to the conventional photosensitive materials such as silver halide emulsion and dichromated gelatine. They also revealed the refractive index fluctuation in uniformly exposed photopolymer sample, which explains the milky appearance that sometimes observed in thick samples.

There are many polymers applications in the industry, but some polymers can be used also as material for holographic register. Photopolymer materials with others components are promising candidates for holographic replications. We report in this manuscript the analysis of some its electro-optical and chemical properties as; diffraction efficiency, pH, resistivity experimental and technique to obtain holograms replication with lithographic techniques.

Experiments of real time holographic interferometry were performed with circular and linear polarized laser radiation. An object with a metallic and dielectric part of the surface was studied. It was found that holographic interferometry on the metallic surface can easily be understood with different combinations of the polarization of the different waves. However, unexpected results were found for experiments with the dielectric. The experiments can be explained assuming that the object wave of a diffuse scattering dielectric is different for illumination with right and left circular polarized radiation. Thus, the interference structure of a hologram originating from these waves is also different, in spite of the fact that the image of the object seems to be the same. A theoretical analysis can be performed extending the well-known Jones matrices for radiation depolarized by dielectrics. Theoretical and practical consequences are discussed that refer to the polarization structure of light and to holographic interferometry.

It is well known that one of the basic functions of security holograms is the maximal complication of their nonauthorized reproduction, in other words - counterfeiting. To solve the problem, concealed images that can be observed only under special conditions are placed into a structure of the hologram. A popular way to place concealed image in Diffractive Optical Variable Device (DOVID) is integration into DOVID's structure of a Concealed Laser-Readable Image (CLRI). Traditionally CLRI is a 2-D Computer-Generated Hologram (2-D CGH), which is a digitized Interference Fringe Data (IFD) structure, computed under the scheme of Fourier-hologram synthesis. Such hologram provides inspection of second level with portable laser reading devices. While it is being read, two (+/- 1 order of diffraction) identical images are formed. In this work a special kind of CGH, which restores image only in one diffractive order or two different images in +1 and -1 orders of diffraction proposed.

The characteristics of holographic recording in the presence of phase noise caused by air disturbances and by vibrations were studied. Diffraction efficiencies were calculated using the finite-difference time-domain method. The simulation results show that the amplitudes of fringes decreases with increasing phase noise, and thus diffraction efficiencies decrease. A novel method of phase compensation for holographic data storage is proposed. Interference fringes are incident on a charge coupled device (CCD) camera symmetrically positioned in relation to the recording media, and the fringes in the media are estimated using the fringes monitored by the camera. The phase information is calculated using a fast Fourier transform, and a phase modulator is set in the reference beam's path and driven to reduce the phase error, so that the phase at the CCD camera is stabilized. With this method, the standard deviation of the phase error is decreased to less than 1/10^th that of the conventional method. The diffraction efficiencies of angle multiplex recording using photopolymer were measured. The diffraction efficiency with phase compensation at 0 degree was 700% larger than without it, and the total relative multiplexing number improved by 50%. When digital data are recorded, we found that the histogram distribution of the symbol "1" (a white signal) was a Gaussian density and the distribution of the symbol "0" (a black signal) was a Rayleigh density. We also proposed a novel SNR measure suitable for holographic data storage. When this phase compensation method was applied to digital holographic storage in which a spatial light modulator (SLM) was set on reference beam's path, a 5.0-dB improvement in SNR compared with the value without phase compensation was obtained. As holographic data storage can record phase, the proposed method can be made into a feasible technology.

In conventional LED backlight as that used in mobile liquid crystal displays (LCDs), typically the structure consists of a light guide, a diffusing sheet, prism sheets and so on. In this work we would like to propose a novel light guide where we have applied a special diffraction grating technology which provides a high performance with a thinner backlight. The special designed diffraction gratings on the light guide redirects incident light by diffraction to the front direction without the utilization of prism sheets. For testing the performance we made a diffraction grating light guide suited for a 2.4 inch backlight with 4 LEDs in a trial. As a result, the backlight that consisted of a diffraction grating light guide, with either a single or none prism sheet achieved equivalent performance to conventional backlights.

We present results of a fast holographic wavefront sensor. The modal device consists of a multiplexed hologram designed to diffract a single input beam into multiple output beams depending on the amplitude of particular Zernike terms. The aberration and amplitude are determined by the spatial location and intensity of the reconstructed focused spots. The sensing does not require any calculations, so the device is simple, compact and fast. In fact, using several position sensing detectors (PSD), a full description of the wave aberration can be obtained at rates in excess of 100 kHz. The holographic wavefront sensor can be reconfigured for any type of basis set, and is easily adaptable to laser mode profiling. In this talk we will present results of the both the theory and operation of our holographic wavefront sensor.

We report a new method for obtaining non-trivial phase difference between the output ports of an interferometer through the use of shallow diffraction gratings. We show that as opposed to a single shallow diffraction grating-based interferometer (which provides only trivial phase shifts, i.e., 0° or 180°), a pair of harmonically-related shallow diffraction gratings can be used to design interferometers with non-trivial phase shifts between different output ports. More importantly, the phase shifts can be adjusted by simply shearing one grating with respect to the other. This approach does not change the path length relationships of the different interference beams within the interferometer, which is an advantage for metrology and low coherence interferometry applications.

We introduce a new holo-video display architecture ("Mark III") developed at the MIT Media Laboratory. The goal of the Mark III project is to reduce the cost and size of a holo-video display, making it into an inexpensive peripheral to a standard desktop PC or game machine which can be driven by standard graphics chips. Our new system is based on lithium niobate guided-wave acousto-optic devices, which give twenty or more times the bandwidth of the tellurium dioxide bulk-wave acousto-optic modulators of our previous displays. The novel display architecture is particularly designed to eliminate the high-speed horizontal scanning mechanism that has traditionally limited the scalability of Scophony- style video displays. We describe the system architecture and the guided-wave device, explain how it is driven by a graphics chip, and present some early results.

This paper examines the concept of the 'Presence of Absence' in post-mortem photography and holography, drawing upon both historical and lesser-known images as reference. To create a photographic negative one needs the presence of light to expose the light sensitive surface, be it glass, a polished plate or plastic. A hologram may also be created when a coherent light source, for example from a Laser, travels through a light sensitive material and falls upon the subject to be recorded. A holograph however, retains the optical qualities of both phase and amplitude, the memory of light. Both mediums recall, as it were, 'now absent moments', and confronts us with what is 'not there' as much as 'what is'. This paper examines the exploration of absence and presence in post-mortem photography and holography and it's a richly visceral visual language. A photonic syntax can interpret death as an elegant yet horrific aesthetic, the photograph may be beautify screened and yet obscene in its content. In essence one can be a voyeur, experiencing a mere visual whisper of the true nature of the subject. Our Victorian forefathers explored postmortem photography as an object of mourning, and at the close of the nineteenth century when Jack the Ripper had the inhabitants of White Chapel in a grip of fear, photography made its mark as a documentation of violent crime. Today, within contemporary photography, death is now presented within the confines of the 'Art Gallery', as a sensual, and at times, sensationalised art form. In exploring post-mortem imagery, both in holography and conventional photography, absence presents an aspect of death as startling in its unanimated form and detailed in its finite examination of mortality.

Diffractive optical elements are commonly used to produce a regular array of spots or an arbitrary pattern from a single coherent source. A challenge in the use of diffractive elements is the zeroth order in the reconstructed image. An analysis of the zeroth order attributed to fabrication limitations is performed via simulation and the sensitivity of the zeroth order intensity to surface relief height is determined. Two methods are proposed to reduce the zeroth order by introducing a rectangular phase aperture to compensate for the zeroth order complex amplitude, and a checkerboard phase plate to decouple the zeroth order intensity from the central zeroth order and redistribute the energy away from the reconstructed image. The second method is found to be favourable in suppressing the zeroth order and a subsequent analysis is performed to determine the tolerance of the technique to fabrication accuracies.

In this paper, we have investigated real time calculation and display optics of full color hologram with full parallax. In our previous study, full color hologram was realized as the rainbow hologram which discards vertical parallax to reduce computation complexity. Since the color of the reconstructed image changes when observer moves to the vertical direction even a little, proper color reproduction can be obtained only from narrow viewing area. And this hologram has horizontal parallax only. In this study, we employ the image hologram for better color reproduction and full parallax reconstruction. When we calculate the image hologram, we use the virtual window to reduce the calculation amount. By using the virtual window, we could achieve 253 times faster the calculation speed compare with Fresnel hologram using the difference method. The full color hologram is displayed on the holographic television (HoloTV), which uses a part of original optics and LCoS panels of the conventional video projector (Cannon POWERPROJECTOR SX50) to separate and combine color components. From experimental results, computational speed of the full-color image hologram is almost same as the full-color rainbow hologram and color reproduction is better than that of the rainbow hologram. We also could achieve to reconstruct good quality animation.

The quality of a hologram depends on many factors including its resolution, brightness and color reproduction. In a holographic image, good resolution entails that overt and covert images are clearly visible. However, the effects of using the H1H2 method to construct holograms, on the resolution of holographic images have not been investigated to date. In this study, the resolution of images reconstructed from mass-produced color Lippmann holograms using the H1H2 method was evaluated. Silver halide (H1, master hologram) and photopolymer (H2, intermediate and H3 mass-produced holograms) were used as recording materials. Results indicated that the resolution of H3 images decreased progressively as noise in H1 images increased. The noise in H1 images was dependent on conditions related to developing the silver halide and factors related to producing H1. Optimizing the process of creating H1 images was effective in creating high quality H1H2 holograms.

A phase-shifting method by the SLM has been proposed for simultaneous recording of phase-shifted RGB holograms. The phase of RGB lights can continuously be shifted by adopting a LCD panel. A system with a high-resolution reflective LCD panel, a color CCD, and red, green, and blue lasers is developed for recording 3D color images. The phase of RGB reference lights is precisely shifted by moving the diffraction grating on a reflective LCD panel. Since a shifted value of the phase is independent of the wavelength of light in the present method, RGB interference fringe patterns for the practical object can be recorded at once by adopting a high-resolution color CCD. Fine complex-amplitude holograms for reconstruction of RGB images are obtained from recorded interference fringe patterns, and high-quality color images of the practical object are reconstructed from the holograms.

In order to control performance of complex amplitude microelements it is necessary to receive information about amplitude and phase distribution of the field at each point (x,y,z) of the microelement under investigation. Digital holographic tomograph DHT proposed by our group permits in principle to investigate amplitude, phase and amplitude-phase objects. The capability of registration of several angular views of the object during one registration is the basic advantage of DHT. This is performed by a multiple pass arrangements and later by holographic reconstruction of an object at different distances. It decreases significantly the number of registered images used for determination of 3D amplitude and phase distribution in measurement volume, and may in future shorten significantly the measurement time or even allow for tomographic analysis of dynamic media. The analysis of tomographic algorithm best suited for 3D reconstruction based on a few non-evenly captured phase information is given. Numerical reconstruction of symmetrical phase microobject using DHT is presented. For numerical holographic reconstruction of the object the plane wave approximation method was applied. The numerical experiment has proven the possibility of reconstruction of phase for several different reconstruction distances for a certain class of objects and its application for tomographic reconstruction.

Holograms that is allowing 360-degree viewing such as cylindrical holograms, show us 3D images with motion parallax and look-around property. Especially, full parallax holograms - not multiplex holograms - make reproductions with an impressive 3-D feeling. However, it has not been realized by a computer-generated hologram, because it takes huge amount of time to calculate a fringe pattern by a PC. To improve the calculation time, we have studied two types of computer-generated holograms allowing 360-degree viewing: cylindrical holograms and prismatic holograms. A prismatic hologram consists of some plates, and it takes not so much time to synthesize the hologram on each plate, because there are some fast calculation methods on planar shape hologram. For the example of the prismatic holograms, we made decagonal prismatic holograms that consist of 10 plates. On the other hand, a fast calculation method of cylindrical-holograms has been proposed, theoretically. We have implemented the method and verified the efficiency of the method. Both calculated fringe patterns were printed on transparent sheets and were carried out experiments of reconstruction. As the results, the holograms show us 3D images of objects at the center of the hologram. A viewer can see the 3D objects from 360-degree by both eyes. In this paper, we discuss the methods and experimental results.

Computer holographic stereogram (CHS) is useful for holographic 3D TV because it is constructed from the multi horizontal viewpoint plane images and is compatible to the multi camera stereoscopic image. Each hologram is recorded as a slit hologram (element hologram) but total viewing area and the number of the element holograms have been limited to some extent by the size and the resolution points of LCD. Therefore we used two LCDs for CHS and arranged them horizontally and increased the viewing points to two times and considered how viewing area and reconstructed images of CHS were improved.

It is difficult to realize a practical electro-holography, because visual field and viewing zone are limited, which are very narrow to see by both eyes. The problems are caused by the resolution of devices that display fringe pattern, such as on a SLM (spatial light modulator) and an AOM (acoustic optic modulator). A low resolution of device occurs ghost images that are high-order diffraction images of reconstructed images. Therefore the ghost images prevent large visual field and large viewing zone. We propose new configuration of electro-holography using LCD (liquid crystal display) that enlarges visual field and viewing zone simultaneously. The system consists of an array of reconstruction lights, LCD, electro-shutter that is located between SLM and viewer. It is possible to prevent the rays from the ghost images by the shutter, to choose appropriate positions of both a reconstruction light in array and an aperture of electro-shutter. It shows viewers the original 3D objects without ghosts. Switching the combination of positions of reconstruction light and aperture of shutter for all fringe patterns synchronously is possible to see no-ghost images from any point of view. Furthermore, to switching very fast by time-division multiplexing, we can get large visual field and large viewing zone simultaneously. To verify the principle of the method, we made a system and carried out the experiments. In this paper, we discuss the method and the experimental results.

The authors developed the spatial imaging display using holographic images. A hologram playbacks the virtual 3D images, which are floating in the air. We hope these spatial images have motions and interactive changes. We proposed a prototype imaging unit last year. This tabletop display system consists of the hologram and illumination system. When the user puts a special object like a card, the illumination can change the color of light so as to reconstruct various spatial images. The observers can select and view the spatial image of a hologram using this interactive holographic display. However, this system has the restriction of the reconstructing images. The multiple recording and reconstructing technique playbacks ten images at most. To reconstruct numerous images, we switch the key of an interaction from card objects to holograms. In this paper, we describe an intelligent illumination unit, which can recognize the holographic material attached an RFID tag.

The authors developed the illumination systems for reconstructing holographic images. A hologram playbacks fine spatial images. We hope these 3D images have motions and interactive changes. We proposed the holographic imaging display unit last year. This tabletop display system consists of the hologram and illumination system. In this display, the illumination system changes the color of light so as to reconstruct various spatial images. But this system is restricted to the number of reconstructing images. Our research group decided a new development plan to improve its defect. The plan is to focus on the function of switching the illumination light. As the result, this project gives priority to the realization of reconstructing several images rather than to the expression of an artistic motion and interactive change. To revive a vanishing concept, this paper describes interactive illumination system at the request of users.

Light emitting diode (LED) became popular rapidly by the appearance of blue LED. Three color (R, G, B) emitting LEDs are utilized for the image display system by the development of multi color emitting LED. White LEDs became to commercial base by combining blue or UV light sources for excitation and materials for fluorescence. White LEDs are prevailing for general lighting applications. A single tip with the power of 5W became line up for commercial market owing to the research for high intensity LEDs. As a result, LEDs are replacing the market of conventional incandescent lighting and even head lights of the automobile. In this study, we aim to fabricate the white and R, G, B lighting system using high brightness LEDs for the lighting of holograms instead of a conventional halogen lamp.

A new digital hologram data generation and recording method of computer generated holograms (CGH) is described in this paper. The application of using this automatic system can be for display, security and diffractive optical device. As an experimental example, an algorithm of a mathematic model of one-step setup was proposed for creating a white light reconstruction holographic stereogram. The experimental hologram size is 1cm x1cm using 16 perspective CG images, with 3200 pixel x 3200 pixel per each image. A new calculating algorithm was introduced for processing large quantity of data. In addition, a new high speed and high speed digital optical data recording method was applied in the recording process. The method achieves about 0.4 micron spot size resolution. A digital hologram of 1 inch x 1 inch size has been written in 5 hours by this method, where an incoherent single beam is used as the only recording light source. Experimental results show that the digital image processing as well as the recording method is successful and can be applied for display, security holograms, Kinoform and Diffractive Optical Element applications.

We propose an optical encryption/decryption technique based on 2-step phase-shifting digital holography for a cipher system. The technique using 2-step phase-shifting digital holography is more efficient than 4-step phase-shifting digital holography because the 2-step method has less data than 4-step method to restore or transmit the encrypted data. In our system, 2-step phase-shifting digital holograms are acquired by moving the PZT mirror with phase step of 0 or &pgr;/2 in the reference beam path and are recorded on CCD camera. The information data and the key are expressed with random binary amplitude and random phase. Digital hologram in this method is Fourier transform hologram and digitized with 256 gray-level. DC-term removal is essential to reconstruct and decrypt the original binary data information. The simulation shows that the proposed method gives good results for cipher system. The quantization error is also analyzed.

An improved image encryption/decryption approach is proposed. In the encryption system, a binary amplitude image is encoded in the Fourier domain. Then, the encoded image is scrambled with a random binary phase image to produce the encrypted image. Both the encoding and encryption processes are done electronically. The encrypted image is stored in an encrypted phase mask of which the transmittance is proportional to the phase components of that image. In the decryption process, the encrypted phase mask is optically descrambled with another phase mask which has the transmittance identical to phase components of the random image used in the encryption process. The descrambled field is inversely Fourier transformed by a Fourier lens in order to reproduce the original image. The simplicity and the misalignment free characteristics are the most significant advantages of our method. The Fourier encoding process using an optimization algorithm with iteration technique is discussed in detail. The effect of noise on the quality of the decrypted image is investigated. The innovation of the system is demonstrated through simulations. The most critical issue of our technique is that the encryption process requires an optimization search which consumes some computation time so that the system is expected to be applied for unreal-time applications.

In this paper, the chirp volume grating recorded in photopolymer for the optical demultiplexer is presented. By using the chirp grating, the spatial distance of fibers can be controllable. The chirp rate of the grating is investigated. As a result of the experiment, a 51-channel 0.4-nm-spaced demultiplexer with the channel uniformity of 3.5 dB, the 3dB-bandwidth of 0.12 nm, and the channel crosstalk of -20 dB is experimentally achieved.

In this paper the use of a blazed holographic grating extends the filed of view (FoV) of a thin camera system. A blazed grating is designed to shift the center of the object field 10° from the axis. The designed blazed grating provides 69% maximum diffraction efficiency (DE) in the primary order over a 15° FoV. High diffraction efficiency is maintained over a wavelength range from 457.8 to 632.9 nm. The holographic blazed grating is fabricated in photoresist on a 1.5 mm thick glass substrate, index matching with a prism. The prism helps to make an adequate profile of the blazed grating. Experimental results confirm that the center in the object field is successfully shifted by the blazed grating for the FoV extender. This technique can be used to increase the numerical aperture (NA) of various optical systems.

An organic conductor polymer was doped with benzalkonium chloride to get a photoluminescent effect at 560 nm and it was used as holographic material. We used a digital image to generate a hologram in a computer and it was transferred by microlithography techniques to our polymer to get a phase hologram. The transference is successful by rubbing, the heat increment produce temperature gradients and the information in the mask is transferred to the material by the refraction index changes, thus the film is recorded. We recorded some gratings to observe the behavior of photoluminescent light with different frequencies when it is radiated with a green laser beam at 532 nm.

The holographic properties of dichromate gelatin (DCG) doped with natural colorants, in order to change the absorbance spectrum profile, and increasing the material sensibility, obtaining a good photo sensibility in other spectral emission line laser as blue. We showed some basics studies referent possible mechanism to storage information with this doping, and reported results. We show a light description technique to obtain holograms with these colored materials, as some experimental results.

A typical difficulty to display the Fresnel hologram in real time is calculation of huge information. In this paper, we propose a method to define the optimum size of segmentation for the Phase-Added Stereogram, which can generate high quality hologram rapidly, and describe a generation algorithm of the Phase-Added Stereogram using the Fast-Fourier Transform for fast calculation. Moreover, we have built an optical holographic display system for real-time holographic display to implement the proposed method. To generate the fringe pattern, we used 3D information, which is a set of the 3D points converted from a 3D model. Finally, the generated hologram is displayed on the optical holographic display system in real time. In consequence, we could achieved that digital hologram can be displayed at 15 frame/second with 1,000 object points.

In this work we propose a phase material based in Polyvinyl Alcohol (PVA) and Crystal Violet (CV) deposited on a glass substrate with 10 &mgr;m of thickness. In this material we record holographic gratings using a &lgr;=612 nm and reconstruct the image with &lgr;=543.5 nm of He-Ne lasers; the diffraction efficiency was 0.0056% for the first order. The material no requires developing process and is very easy to make. Experimental results are shown.