This paper will give an overview of some recent developments in electroholography for applications in interactive 3D visualisation. Arguably the ultimate technology for this task, it is the only approach having the potential to deliver full depth cue, 3D images, having resolutions beyond that which can be perceived by the human eye. Despite significant advances by many researchers, the high pixel counts required by the computer generated hologram (CGH) patterns in these systems remain daunting - in practice, systems able to calculate and display reconfigurable CGH having pixel counts of more than one billion may be required for 300 mm width, 3D images. Advances described include novel Fourier mode variants of diffraction specific algorithms and parallel binarisation techniques for design of the CGH patterns; computer architectures for effective implementation of these algorithms for interactive CGH calculation; the latest developments in the Active Tiling spatial light modulator technology and novel replay optics arrangements including folded mirror geometries, viewer tracking alternatives and new horizontal parallax configurations. Throughout, the emphasis is optimisation towards implementation as an interactive electroholography system having practical utility. Some recent results from demonstrations of aspects of the technology will be shown. These include monochrome and colour, static and dynamic, horizontal parallax only (HPO) and full parallax, 3D images, generated from true CGH systems with up to 24 billion pixels.

In order to display three-dimensional imagery by computer-generated holograms, it is necessary to draw hologram data on a medium with a resolution on the micrometer order. Conventionally, optical lithography, electron beam lithography, and special laser beam printers designed especially for holograms are used. However these systems are large and expensive, and need special environments such as darkrooms and clean rooms. We have developed a new device that draws hologram data on CD-R (Compact Disc-Recordable) disks, and which is based on a Yamaha CRW-F1 CD-R/RW drive. The drive produces holograms in a short amount of time, at low cost, and at the high resolution of 1.5μm. Moreover, the drive is small, portable and does not require a special environment, so that all of the processes of Desktop Holograming, from hologram calculation to recording, are made possible with just one PC. We evaluated optical properties of the CD-R disk as a viable hologram recording media. There are characteristics that are different from conventional media, because hologram data is recorded on spiral shaped grooves. We propose a new calculation method of hologram data suitable for a CD-R disk in order to display three-dimensional imagery. Using this method, we carried out optical experiments and it showed reconstructed three-dimensional imagery on CD-R disks successfully. In this paper, we discuss the optical properties of the CD-R disk, calculation method, and the experimental results.

A real-time color holography system is developed using a high-resolution reflective liquid-crystal display (LCD) panel that consists of a 1400x1050 array of square pixels with width of 10.4 micron. Red, green and blue images with high resolution are reconstructed from the holography system with a red laser diode (LD), a green laser and a blue lightemitting diode (LED) as the reference light. The reconstructed color image with high resolution can clearly be observed under the room light. Directly viewable color images with both eyes or images in the wide visual field are reproduced using the 3-channel LCD modulator. The viewing-zone angle or the visual-field angle of the 3-D display system can be expanded up to about 9 degrees using three LCD panels. Fringe patterns for a practical object are also recorded by a high-resolution CMOS sensor, and a moving image of the object is reproduced from the fringe patterns by the developed holographic display system.

The specification of hologram image is the full parallax 3D image. In this case we can get more natural 3D image because focusing and convergence are coincident each other. We try to get practical electro-holography system because for conventional electro-holography the image viewing angle is very small. This is due to the limited display pixel size. Now we are developing new method for large viewing angle by space projection method. White color laser is irradiated to single DMD panel ( time shared CGH of RGB three colors ). 3D space screen constructed by very small water particle is used to reconstruct the 3D image with large viewing angle by scattering of water particle.

In this report, computer-generated holograms(CGHs) synthesized from projection images of real existing objects are considered. A series of projection images are recorded both vertically and horizontally with an incoherent light source and a color CCD. According to the principles of computer tomography(CT), the 3-D Fourier spectrum is calculated from several projection images of objects and the Fresnel CGH is synthesized using a part of the 3-D Fourier spectrum. This method has following advantages. At first, no-blur reconstructed images in any direction are obtained owing to two-dimensionally scanning in recording. Secondarily, since not interference fringes but simple projection images of objects are recorded, a coherent light source is not necessary. Moreover, when a color CCD is used in recording, it is easily possible to record and reconstruct colorful objects. Finally, we demonstrate color reconstruction of objects both numerically and optically.

A diffusive film characterized with a directional property was developed. This new type of diffusive film is achieved with a new technology derived from holography. Directionality of diffusive film is characterized because it diffuses the light from the determinate angle strongly more than other angles. This discriminative property is consequence of the diffusive film structure that consists of different index transparent materials. Additionally, The film is a volume type diffuser, and the surfaces are almost flat so it is possible to laminated it to various part of other elements without remarkable affecting the diffusing properties of the film. Moreover, durability of this film is actually enough to consumer applications. With these remarkable properties, this diffusive film can widely applied to display systems etc.

A method of hologram bandwidth reduction and a method of size change of a 3D image are described. Spatial frequency bands of a Fourier-transform hologram (FTH) are superimposed for reduction of the bandwidth and for production of a continuous periodic FTH. Resolution of the image is improved by the superimposing method. The second hologram for reconstruction of the magnified 3D image is produced by connecting a number of small holograms clipped from the original FTH. Image depth capable of magnification is extended using several FTHs. Experiments using the CGH shows that depth of the 3D image can be perceived by watching images reconstructed on many Fouriertransform planes with different distances from the hologram. It is also shown that numbers of rays of light illuminated from the second hologram reconstruct similar 3D images of various sizes of the same object. Distortion of the image due to the magnification can be avoided over the wide range of magnifying power.

A novel algorithm is presented for hidden-surface removal in digitally synthetic holograms. The algorithm is able to work with full-parallax holograms and remove obstructed fields in the object wave emitted from threedimensional (3-D) surface objects. This algorithm is initially discussed as a rigorous procedure to obtain fields behind a tilted planar surface by using the rotational transformation of wave fields, and finally results in the silhouette approximation for reduction of computation time. Reconstructions of holograms created by using the algorithm are demonstrated.

Holographic optical sectioning using off-axis-image plane holography has been combined with microscopy. Various optical configurations have been used, including grating interferometers and Mach Zehnder forms of interferometers. Experimental results are presented, using various mounted specimens.

The division of a picture surface into discrete units makes it possible to structure an image in a unique way. Holographic imaging processes which employ computer graphics as subject matter frequently employ sequential exposures to small sections of the hologram plate or film. The making of complete holograms from hundreds of small slices or squares has been refined in recent years to enable millions of 1mm hologram pixels to be successfully exposed to make one visually continuous three-dimensional scene. These techniques of making one hologram through the exposure of thousands of discrete image elements enables the subject and its lighting to be shaped and changed very subtlety over every tiny picture unit. In some ways the small holographic pixels of fringe digital holograms are similar to the glass and gilded tesserae of early mosaic art works. This paper compares the different compositional possibilities between early glass and gold mosaics, optically formed fringe digital holograms and my optical and recent tesserae holograms. This recent use of small hologram fragments with gilding and silvering is set against the context of the interrelationship of artistic pictorial style and the technical evolution of holographic image making.

The different concepts of artistic holography have contributed to the development of new ways of understanding reality. Holography makes it possible to express different visions of the recorded subject. In this work, from a primary portrait recorded with a pulsed ruby laser, a new kind of portrait will be created. The extremely realistic image of the master hologram will be transformed in a secondary expressionist multicoloured hologram. Using an emulsion manipulating technique before exposure, the portrait is changed, in order to achieve new visions of reality.

In my presentation, I will explain the application of the concepts and techniques I have mentioned in the poster and exemplify them in the works of art, book and slides which accompany the poster.

The author with technical education background (Ph.D. in holography) shares her 3+ years of experience working on intellectual property (IP) issues that includes patents, trademarks, and copyrights. A special attention is paid to the patent issues: the application procedure, the patent requirements, the databases for prior art search, how to make the cost efficient filing.

The star formation distribution and internal movement in the Galaxy is the key variable to probe into the evolution and formation process of the Galaxy. To this end, the diffraction grating is required, which can achieve high dispersion and efficiency by direct vision grating in a wide visible wavelength region. We propose a grism that fulfills consisting of two prisms and a diffraction grating with comb-like thin reflective plates arranged in parallel. A beam of light reflected by this grism on a reflective plate spreads in the diffractive distribution determined by wavelength and grating period. In the case where high order diffraction light is employed, the structure is designed such that the highest possible efficiency is given to the wavelength at the order that satisfies interference conditions in the positive direction of the reflective plate. We design and calculated by using the program based on the Rigorous Coupled Wave Analysis (RCWA) in order to obtain the optimum conditions for high efficiency of 80% in a wide wavelength region by using the grism with high-order diffraction.

The basic aspects of animated and stereographic rainbow images making technology are considered in this paper. These images are devoted to include in Optical Security Devices (OSDs) in order to increase its structure complexity and to improve its protective properties. They provide on the one hand the simple identification on the visual level of verification and on the other hand the sufficient reliability against counterfeit. The last one is achieved at first by the division of the elemental unit on the regions of any adjusted shape with outline of the precision that is inaccessible for recreation without Electron Beam Lithography Equipment (EBLE), which is used for OSDs recording, and, secondly, by the used encoding methods. In the context of the paper the theoretical discussion of the diffraction on elemental diffractive grating was carried out. The acquired results have been allowed to create the software utility that models the behaviour of the anigram or stereogram. The analysis of examples of the sythetized by the given methodology anigrams shows that there is peculiar for them the effects of the stereoscopic perception. So the investigations on combined methodology of animated stereographic images synthesis were carried out. There were recorded the stereographic, animated and the animated stereographic images as a parts of demonstrational holograms of STC “Optronics”, Ltd.

Usually in auto stereoscopic display, there are two problems. The first problem is that large image display is difficult, and the second problem is that the view zone (which means the zone in which both eyes are put for stereoscopic or 3-D image observation) is very narrow. We have been developing an auto stereoscopic large video display system (over 100 inches diagonal) which a few people can view simultaneously^1,2. Usually in displays that are over 100 inches diagonal, an optical video projection system is used. As one of auto stereoscopic display systems the hologram screen has been proposed^3,4,5,6. However, if the hologram screen becomes too large, the view zone (corresponding to the reconstructed diffused object) causes color dispersion and color aberration⁷. We also proposed the additional Fresnel lens attached to the hologram screen. We call the screen a “hybrid hologram screen”, (HHS in short). We made the HHS 866mm(H)×433mm(V) (about 40 inch diagonal)^8,9,10,11. By using the lens in the reconstruction step, the angle between object light and reference light can be small, compared to without the lens. So, the spread of the view zone by the color dispersion and color aberration becomes small. And also, the virtual image which is reconstructed from the hologram screen can be transformed to a real image (view zone). So, it is not necessary to use a large lens or concave mirror while making a large hologram screen.

A stereogram differs from the 3D picture often called stereo pair in appearance. There is no need of special viewer or glasses for stereopsis when viewing the sterograms. It is possible to intuitively carry out the intuitive estimation of depth perception by simultaneously viewing two pairs of stereograms which are arranged the upper and lower sides, or the right and left sides. In this study, modified digital color stereograms are directly viewed on the LCD screen or hard copy images by means of (a) crossing view method or (b) parallel view method. The apparent depth perception of stereograms can be effectively demonstrated by an adjustment of the viewing distance between the eye position of an observer and the plane of a stereogram rather than by altering the size and its arrangement of basic patterns which construct the plane images for steropsis. The visual effect of depth perception in the modified digital stereogram using sharpening filtering operation are discussed in connection with the modified various stereograms under the specified conditions: the number of pixel resolution and color bit levels.

The objective of this research program was the development of a technology for the industrial manufacturing of high efficiency HOE (Holographic Optical Elements) with predetermined spectral characteristics and angular selectivity ranging in format from few square millimeters to square meters. The developed technology includes the machine fabrication of precision holographic films (2 to 30 micron thickness) on glass or plastic substrata, and chemically and thermally adapted hologram development processes. The desired optical properties of the holographic material for a specific technical application are determined during the making of the film and are modified during the exposure and the development of the HOE. This is achieved through the use of filler material to swell or shrink the hologram and a specific development process to fix the desired spectral properties of the film. The developed technology extends the applicability of dichromated gelatin ( DCG) into the blue and infrared spectral domains. The effects of the holographic layer deposition and of the development process on the holographic properties are illustrated with electron-microscope photographs of the cross section of the hologram. The photographs reveal the presence of the nano-size voids that are generated during the hologram processing. These voids are regarded as the cause for bandwidth enlargement of the HOE.

Holography is the most fascinating technology for three-dimensional imaging. But despite of many decades of research, the seek for an ideal recording material has never been given up. From all ultra-fine materials, silver bromide emulsions with very small grain sizes have the highest sensitivity. In recent years however, many traditional manufacturers discontinued their production. Meanwhile, newcomers succeeded in manufacturing emulsions which are very suitable for holography, concerning extremely high resolution, brigthness and sensitivity1. But two problems may still linger: First, the deficient market situation for production and application on this field. Second, the reputation of the system of being extremely complicated for laboratory preparation. In such a crucial situation, the authors have succeeded in presenting a laboratory procedure for making do-it-yourself materials available to any expert who is well versed in holography, and who disposes of normal darkroom equipment2. The methodology is based on precipitation using the traditional double-jet method according to Thiry and predecessors3. But sensitization is carried out by a diffusion process according to the procedure as proposed by Blyth et al.⁴ Thus, precipitation and coating on one side and sensitization on the other one are separated strictly from one another. Efficient desaltation is an important process too, warranting the high opto-mechanical quality of the layer. The material has been sensitzed for HeNe-Laser radiation (632,8 nm) only up to now. The mean diameter of the silver bromide grains is about 15 nm, as determined by transmission electron microscopy (TEM). Phillips-Bjelkhagen Ultimate (PBU) or Fe³⁺ rehalogenation bleach are applied successfully^5-6. In final result, a new generation of holograms with ultra-high resolution, proper contrast, excellent sharpness and light brightness has been obtained. Holography belongs to an advancing technology where the search for an ideal recording material is still going on. Of these materials, the ultrafine grain silver bromide emulsions are unsurpassed in sensitivity. But in recent years many traditional manufacturers discontinued their production. In such a critical situation, the authors have succeeded in developing a new technology to make do-it-yourself materials of very high quality. The procedure involves elements of two different methods: The traditional double-jet method by pouring silver nitrate and potassium bromide into a vigorously stirred gelatin solution, and a diffusion process to sensitize the coated layer efficiently. The material has been sensitized for He/Ne-laser radiation by 632.8 nm. Denisyuk holograms of real 3D-objects were obtained in ultrahigh resolution, excellent brightness and clarity with CW-C2 developer and PBU rehalogenation bleach according to Bjelkhagen et al. The material is characterized by TEM, reflexion spectroscopy, and other methods. The new results have been involved in university education already with great success. The fundamental principles of the methodology as well as new results by application in intellectual and hybrid systems were reported.

Irradiation of dichromated polyvinyl alcohol and dichromated polyacrylic acid DC(PVA-PAA) at 365 nm was investigated in order to understand the involvement of the polymeric matrix in the reduction process of the Cr(VI) leading to the formation of the hologram. The photochemical evolution of the matrix was directly correlated to the disappearance of the absorbing species, chromium(VI). A special attention was paid to the absorption profile of the films. Due to the impermeability of the polymer, no oxidation proceeded. The reduction of Cr(VI) into Cr(V) induced the formation of carboxylate species perfectly correlated with the consumption of carboxylic groups. Besides the acido-basic reaction undergone by the carboxylic groups, the reduction of Cr(VI) provoked the cross-linking of the polymer. Each polymer appears to play a specific role in the mechanism.

Lippmann photographs can, in principle, reproduce the entire incident spectrum at every point in the recording. This paper presents a comprehensive model of the Lippmann process, including exposure, chemical processing and subsequent reproduction. The main emphasis is on the optical properties of emulsions, where the theory of radiative transfer is used to obtain a detailed description of how interference patterns are formed in the presence of scattering particles and absorption. The results presented illustrate the reproduction fidelity of Lippmann photographs and highlight the most significant factors influencing their quality. Whereas the reproduction of monochrome sources is excellent, locally broadband signals are more problematic. Several practical measures to improve upon broadband performance are discussed.

The formation of holographic surface relief gratings (SRGs) on azobenzene containing polymers are simulated using the moving particle semi-implicit (MPS) method. The gradient force of optical electric field and the influence of surface tension were considered as the driving forces for mass transport. The particle motions of SRG formation are calculated by giving particles two beams interference with various polarization states. The model for time evolution of SRG formation coincided with experimental results qualitatively.

We do a modification of a synthetic resin which is feasible to used with holographic base film with this technique do not required any develop process in order to obtain phase hologram.

We propose a narrowly-shaped setup containing two prisms symmetrically placed along a straight line. This method features (1) an easy alignment, (2) the capability of hologram multiplexing using array light sources. In the proposed optical systemm, prisms' apex angles are limited for two waves interference because of the total reflection at prism's boundary. Therefore, we should take this obstacle into consideration to design the setup. As a simplified calculation model, we assume that the wavelength of the light source is 780 nm, the refractive index of the prism is 1.51, and the focal length of the collimating lens is 10 mm, the apex angle of the first prism is 120 degrees, and that of the second prism is 90 degrees. If the largest oblique incident angle of the first prism is 10 degrees, the distance from light sources to a recording media becomes 45mm. The validity of our optical setup is confirmed experimentally by writing some holograms.

Modern photolithography is based on the use of excimer lasers with the radiation wavelength of 193 nm and 157 nm. Further steps aimed at achieving a higher resolution of displayed structures lead to a reduction of the radiation wavelength and a considerable rise of the cost of lithographic system. In this connection, the search of alternative image generation methods being suitable for the use in extreme short-wave photolithography is becoming especially urgent. In order to develop an alternative method based on optical holographic principles, two versions of schemes for recording and reconstruction of relief-phase reflection holograms providing speckle-free images of two-dimensional microscopic objects have been scientifically justified and experimentally verified. The first of them is based on the replacement of projection objective with relief-phase reflection hologram-projector registered on chalcogenide glassy layer. The second one is closed to the near-field correction being conventional for photolithography. As a result of this work, samples of holograms-projectors forming an image of the photolithographic test-object with the characteristic size of 0.8 μm at the wavelength of 0.488 μm were obtained. On the whole, the results show an availability of further works aimed at the implementation of optical holographic methods into short-wave photolithography.

Crystallization plymerization can be generated in the glucose with fructose when ultraviolet light it is irradiated; the crystallization polymerization opens up possibilities to the material, as matrix to record holographic images, applied conventional microlithography techniques with ultraviolet ligth. The masks with the information is transferred as a modulation of polymerized regions, where were exposed to UV light and regions without plymerization not exposed to UV light. Shows phase modulation by refraction index. Because the polymerized areas presents less density, than the nonexposed areas, changes the emulsion density can be interpreted as changes of refraction index. A developed process is not required, because the material is developed itself; for a physical-chemical mechanism well-known as process cured reaction.

We present a computational method for image reconstruction with a high degree of reality from a computergenerated hologram (CGH). As also seen in the field of computer-graphics, rendering methods are indispensable techniques for displaying realistic 3D images from CGH. The proposed rendering algorithm takes into account multiple reflection, transmission and shadow of lights among objects. Objects are expressed using the patch model in this method. In the object-light calculation stage, reflection, transmission and shadow of incident light are calculated on each patch. Propagations of these three lights to every other patch and a hologram are then calculated. The incident light of a patch is the summation of these lights propagated from other patches and illumination light, which lights up all the objects. Object-light on a hologram is sought from the summation of all of the lights from each patch. In addition, we fabricate full-parallax CGHfs of 3D object models using this method, and the reconstructed 3D holographic images are shown for demonstration purposes.

It becomes quite easy to calculate over one hundred million pixels computer-generated hologram of three dimensional objects, even with normal personal computers. On the other hand, it is not so easy to output the calculated result as a hologram that must have micron order resolution for practical three dimensional displays. It is possible to use the electron beam writer and the laser plotter, which are used to make masks for integrated circuits. However, these equipments are quite expensive and not suitable for personal use. There have been reported some results of compact and inexpensive direct fringe printing. They use a laser and an x-y stage, and the fringe pattern is written point by point, which takes very long time. We are developing area by area writing printer, which consists of the laser, the x-y stage and a liquid crystal panel as a spatial light modulator. A fractional part of the entire holographic fringe is displayed on the liquid crystal panel, and the demagnified image of it is recorded on a holographic plate. Then the plate is translated by the x-y stage to write next part of the fringe. The system configuration and preliminary results are described.

Backside transient interferometric mapping method is a useful tool for ns-resolution imaging of transient changes in heat energy and free carrier concentration in semiconductor devices during high-energy electrical pulses. In this contribution we investigate the sources of errors in the extracted phase, which are specific to the spatial phase and reflectivity profile of the semiconductor device structure and to the used FFT extraction method. We show that the phase and reflectivity profile of the sample related to the structure of the top layers causes undulations in the phase, thus decreasing the phase extraction precision. To minimize the undulations, an optimal spectrum filter for the FFT method is proposed. In addition, the noise and fringe discontinuities are found to result in defects in the phase profile. In order to isolate these defects time efficiently, a pre-processing of the wrapped phase image is proposed. It effectively reduces the requirement for the unwrapping to a small region. The path independent method or the pixel-queue algorithm is then used for the unwrapping, which do not allow spreading of the defects. The findings are used to make a full-automated evaluation of the phase images.

Fundamental experiments of multiple image recording were carried out for university students to understand the basic concept of the 3D image storage. We performed holographic image recording experiments using simple two beam interference. Multiple image recording of 2D and 3D was successfully performed.

The first method for designing the amplitude hologram was proposed by Lohmann employed properties of irregular amplitude diffraction gratings, that is, every slit of the diffraction grating is smashed into pieces where every piece has a position (P) and a wide (W), the control of these parameters enable the detour and the change of a wave front to one that we want. Though it has a few inconveniences, which are show in this work. One analysis of the diffraction patterns with various geometric apertures differences to the Lohmann type is showed too. These coding methods are apply to Fourier and Fresnel holograms type. We shown the effect of the surround that each one causes in the diffraction pattern in order to determine the conditions for the better visualization of the reconstructed image.

Repositing a single exposure hologram to its original place precisely and real-time measuring the phase distribution of the deformed object wave are the foundation of real-time holographic interferometry. In general, phase distribution of the under testing object wave must be determined by measuring the corresponding intensity distribution of several phase shift interferograms. An digital method is introduced in this paper, it greatly simplify the process of determination for the phase distribution of the under testing object wave by using only one interferogram and reduce the precise requirement of the real-time hologram reposition. Some experimental examples are also given in the paper.

Polymer matrices like PVC and a blend of PVA/PAA is introduced as new holographic media that cause red sensitivity with methylene blue. Unlike methylene blue sensitized polymers like PVA, PMMA, gelatin etc, the change of state occurring for methylene blue on laser irradiation on PVC matrix was found to be permanent. No recovery of dye on the irradiated spot was observed on storage. The outstanding properties of this material are its excellent optical clarity, insensitive to humidity, economical, ease of fabrication, absence of dark room storage etc. The recovery of dye in conventional MBPVA matrix can be delayed by blending PVA with PAA. Optimization of the ratio of PVA/PAA, the sensitizer concentration, pH, energy, diffraction efficiency measurements etc are done. pH is found to have a great influence on the recovery of the dye in this matrix. The effect of monomers in improving the diffraction efficiency on these dye doped polymer system is also evaluated. A comparative study is done on these polymer matrices and holographic gratings were recorded on these films from a He- Ne laser operating at 632.8 nm.

The process of any movement of real object can be recorded and displayed by a multiplex holographic stereogram. An embossing multiplex holographic stereogram and a multiplex rainbow holographic stereogram have been made by us, the multiplex rainbow holographic stereogram reconstructs the dynamic 2D line drawing of speech organs, the embossing multiplex holographic stereogram reconstructs the process of an old man drinking water. In this paper, we studied the visual result of an embossing multiplex holographic stereogram made with 80 films of 2-D pictures. Forty-eight persons of aged from 13 to 67 were asked to see the hologram and then to answer some questions about the feeling of viewing. The results indicate that this kind of holograms could be accepted by human visual sense organ without any problem. This paper also discusses visual effect of the multiplex holography stereograms base on visual perceptual psychology. It is open out that the planar multiplex holograms can be recorded and present the movement of real animal and object. Not only have the human visual perceptual constancy for shape, just as that size, color, etc... but also have visual perceptual constancy for binocular parallax.

The use of holograms as authentication or security devices is the most valuable application of holograms yet devised. In 20 years, this has developed from the first use of a hologram on credit cards, to the situation today where governments turn to holograms as a key security feature on the protected documents they issue, including banknotes, identity documents and tax banderols. At the same time, holograms (and related devices) are the most recognised visible feature used to authenticate and protect branded and OEM products; this sector covers the gamut from CD jewel-box seals to the protection of safety-related items such as medicines and vehicle replacement parts. There has been creative synergy between the commercial suppliers of such holograms and the practical holography community. But new technologies are coming forward to challenge the role of holograms, a challenge that is aided by the counterfeiting of security holograms. What are the characteristics of those technologies and can holograms provide similar resources to users? Examples of collaboration between hologram producers and producers of other technologies to create combination devices suggest a possible route forward for holography to maintain its role in authentication and security. By scrutinising and adapting to needs, often by combination with other techniques, holographers may be able to retain their role in this important application.

In a previous paper we have described that some dark shadow areas appeared among the interference fringes in real-time holographic interferometry and we pointed that the appearing of these dark shadow regions are the phenomena of caustic in Geometry Optics. These dark shadow region bears certain relation with the interference fringes. The quantitative relation between caustics and real-time holographic interferometry in the experiments of mode I crack and mode III crack were studied in detail. The quantitative relation introduced theoretically in this paper and compare with mode II crack. Based on these relations, holographic method and caustic method can be combined together in interferometry and it can be used as a powerful tool for scientific study and might lead to a wide application in many fields.

The Columbia Career Center high school SPIE chapter has created an educational CD-ROM to teach holography to students on the threshold of a career path in Photonics. This paper examines the development of the CD-ROM as an educational project from the perspectives of both teacher and student. Holography has been used successfully in educational institutions as a motivational tool for students and a vehicle for the teaching of a wide variety of skills. These include problem solving, teamwork, safety, communication, research, mathematics, analysis of data, documentation, equipment handling, and knowledge of light theory, which involves the principals of reflection, refraction, diffraction, interference and polarization. All of these skills are essential to the photonics industry and, as a result, holography is considered by the Center for Occupational Research and Development (CORD)1 to be a national photonics skill standard for Laser Electro-optical Technicians (LEOTs). Thus, training in holography - using both simple and advanced techniques and equipment - prepares students for a variety of vocations involving laser technology. However, the teaching of holography can be beneficial at many different levels of education, including middle and high school students, college students and interested adults. The educational CD-ROM, "Making Holograms," is the first of its kind. It includes both simple, single beam holography using a laser pointer, and more advanced split-beam setups using helium neon lasers. This paper outlines both the benefits and challenges involved in the production of an educational CD-ROM on holography by high school students and their advisor in an SPIE high school chapter.

A new generation of holographers bring to the medium, a knowledge of dimensional imaging, many of them with related skills learned in high school. Digital holography opens up a variety of techniques and processes, expands the user base and makes literally anything possible. Student artists at the Ontario College of Art & Design create thought provoking imagery from video, film, photography and computer graphics.

August Muth speaks about the origin of the holographic lab Aurorean, his work, and the work of The Light Foundry. Characteristics of producing large format dichromate holograms, and solid form holographic sculpture in heavy glass will be reviewed, as well as the versatility and general parameters of dichromate emulsions.

This is a collection of tributes to Stephen A. Benton. Some of the tributes were presented at a special celebration of his life and works on Wednesday, 21 January 2004 at the IS&T/SPIE 16th Annual Symposium on Electronic Imaging. Other tributes included were collected in writing after the celebration.