We have previously reported1 the advantageous applications of optical fibers in holographic systems. Herein we wish to discuss additional developments that include an HOE diffuser, a fiber interferometer that serves as a beamsplitter,and a technique that compensates rigid body motions in holographic interferometry.
The technique of holography used in a neutrino experiment during 1985 in the 15-foot cryogenic bubble chamber at Fermilab is presented. In this technique, a modified in-line recording method is used to produce holograms of neutrino interactions. In these high energy interactions short-lived particles are produced which decay in times of order of 10-13 seconds. Holography gives a high resolution over a long depth of field compared to the conventional photographic recording technique. A pulsed ruby laser with an opto-electronic feedback circuit allows the generation of long pulses (a few tens of microseconds). One hundred thousand holograms were recorded during the experiment. An evaluation of the recorded holograms is presented.
The use of optical fibers in connection with cw lasers has already found many holographic applications. Investigations of obscured or remote objects or studies in difficult environments using holography and hologram interferometry are now possible with fibers. The development of pulsed fiber holography has opened new interesting applications for investigations of dynamic events as well as medical, endoscopic holographic technique.
In this paper optimized parameters of optical configuration of Holographic Wavelength Demultiplexer(HWD) has been obtained with aberration balancing. The wavefront aberration caused by wavelength shift has been minimized. The image size of a point source formed by HWD was found with ray tracing. For reducing the size of the image, we proposed a phase compensation function and calculated the image size. The phase compensation could be achieved by Computer-Generated Hologram(CGH).
Integral holography is the integration of multiple exposures of motion picture film that have been translated into holographic form. Because integral holograms are formed from motion picture film, there are no limits on the subject matter. All of the cinema and video techniques known today can be utilized to record and mix imagery.
A practical method has been developed for converting laser-viewable cylindrical holograms into white light viewable cylindrical holograms. The method is generally usable for converting any laser-viewable hologram into a white light viewable hologram, and represents a class of optical transforms which may be useful in forming special purpose holographic optical elements (HOE) and performing certain image-processing operations.
Holographic artists using continuous wave (cw) lasers are restricted to working under vibration isolated studio conditions, with mainly rigid, still subject matter. The pulsed laser increases the artist's scope to include live subjects, together with the possibility of operating outside the studio. The paper gives a state-of-the-art comparison between cw and pulsed holographic practice. Some of the problems and restrictions associated with the use of pulsed lasers are discussed, together with techniques for diffusion and illumination control, maintenance of beam quality, and the use of appropriate photochemistry. The paper will include a short historical background to pulsed holography by artists with some examples of individual work.
In the following, I will describe the past, present and future of holographic art in Japan. The history and current situation of holography in general, as described by Prof. Tsujiuchi in his paper last year, will not be covered here.
Just over two years ago a small group of holography enthusiasts formed a company with the aim of developing a machine that could mass produce holograms. Two of their members had been involved in running a retail business, and when they introduced holograms to their list of items for sale they found demand outstripped supply.
A curriculum for beginning holography classes is presented, consisting of seven different types of holograms, requiring no more equipment than a laser, beamspreader, and a mirror. Of these seven holograms, three are white light viewable, and two of these are image plane types. In addition to the software, hardware in the form of a novel isolation device dubbed the "Big Beam" is described.
Experimentation was carried out to evaluate holograms for use in training and as job aids. Holograms were compared against line drawings and photographs as methods of presenting visual information needed to accomplish a number of tasks. The dependent variables were assembly speed and assembly errors with people unstressed, assembly speed and assembly errors with people stressed, the percentage of discovered errors in assemblies, the number of correct assemblies misidentified as erroneous, and information extraction. Holograms generally were as good as or better visual aids than either photographs or line drawings. The use of holograms tends to reduce errors rather than speed assembly time in the assembly tasks used in these experiments. They also enhance the discovery of errors when the subject is attempting to locate assembly errors in a construction. The results of this experimentation suggest that serious consideration should be given to the use of holography in the development of job aids and in training. Besides these advantages for job aids, other advantages we found are that when page formated information is stored in man-readable holograms they are still useable when scratched or damaged even when similarly damaged microfilm is unuseable. Holography can also be used to store man and machine readable data simultaneously. Such storage would provide simplified backup in the event of machine failure, and it would permit the development of compatible machine and manual systems for job aid applications.
In this paper a review of the work by Agfa-Gevaert(1) on the processing of white light reflection holograms will be given. The work that is reviewed was mainly concentrated on three questions: -Which is the form of the silver particles after developing? -How is the surface of the gelatine layer structured by the developing agents? -How can the grain growth of the AgX be controlled by the composition of the rehalogenating bleach solution?
A low scatter silver halide based film has been developed for the mass production of copy holograms on the AHS1 Holocopier system. Machine-compatible replenishable chemistry was devised to be used in conjunction with the film. The primary emulsion has now been sensitised to produce both blue/green and red sensitive film. The holography programme at Ilford has included the development of special red shifting chemistry and light stabilisation techniques.
Unslanted diffraction gratings were recorded in a new phase hologram recording material, DMP-128, under development at Polaroid Corporation. The diffraction efficiency of the resulting gratings was measured as a function of reconstruction angle and compared to results calculated from an "eigenmode" analysis. Good agreement between experiment and theory was observed. Exceptionally large (0.08) changes in the refractive index were produced by moderate (15mj/cm2) exposures of DMP-128, with no evidence of saturation of the index change.
A method for recording color reflect ion holograms is presented. The spectral and angular selectivity, signal-to-noise ratio and brightness of the reconstructed color images are improved greatly. Silver halide light-sensitive materials are utilized. Water-soluble substances are introduced in the gelatin layer both in recording and reconstruction.
Commonly used chemicals for processing holograms pose specific health hazards when contamination occures. It is advisable that holographers educate themselves, employees, and students regarding ways to avoid contamination, and as to the dangerous properties inherent in these processing materials.
Interferometric techniques including hologrametry, both classical and electronic, present high sensitivity making difficult its practical use in real-time. The introduction of the differencial concept as moire evaluation techniques permits to use with advantage an arbitrary reference pattern within the correlation range. The carrier spatial spectrum can be directly the interferogram fringe pattern instead of the original interference pattern of wavelength dimensional scale. A moire techniques is in itself an optical processing method reducing evaluation time which is advantageous when real-time response is desired from hybrid metrological systems. The moire evaluation is performed via a dynamical digital memory that executes arithmetic operations on two frames temporally in sequence, at TV rate. These characteristics of the moire evaluation techniques can be implemented on a real-time holographic (or speckle based) hybrid system with great practical advantage for dynamical studies.
The growth of greenhouse produce in the northern regions of the country is not economical because large amounts of heat are required during the cold season. It has long been recognized that one solution would be to heavily insulate large areas of a greenhouse to prevent heat loss and then use optical devices on the remaining glazing to distribute the incident light throughout the greenhouse (Figure 1). The design, fabrication and installation of holographic optical elements for this purpose is reported here. The ultimate goal is not necessarily increased yields or an economic superiority over imported produce. Since locally grown produce can be marketed rapidly and since varieties can be chosen which do not sacrifice quality for durability, local produce from holographically illuminated greenhouses will be economically viable so long as there are reasonable yields even if the technique does not result in prices competitive with produce grown in warmer climates and shipped to northern markets. There are varieties of effects here on growing plants that are unique to holographic lighting. For example, different portions of the spectrum are delivered to the plants at different times of the day and diffracted light often arrives at the plant from unusual directions.
Phase compensation of an aberrating medium can be achieved with image holography and a rotating diffuser in the recon-struction beam to average speckle noise. We show that the image hologram can also be used in the object plane to achieve the same result. Both amplitude and phase holograms can be used in these experiments. The results were achieved with a three-dimensional phase aberration so that longitudinal magnification and depth-of-focus effects limited the quality of the reconstructed image. With three-dimensional aberrators, one must be careful of the exact location of the image plane when recording the hologram and its placement in the reconstruction process.
This paper presents newly developed optical design techniques for a shallow-type POS hologram scanner. POS scanner optical design involves design of the scan pattern to read the bar code and design of the detection system. For scan pattern design, we have developed a "readability map" method and a "scanning diagram" method. Detection system design took into account laser safety standards, and we used a technique for estimating the power of the detected signal. We have realized a shallow-type POS hologram scanner which is only 16cm high and can be operated from a sitting position.
A new lensless holographic line scanner has been developed. The scanner consists of two holographic elements, a holographic disk with a flat-field focusing function and a newly devised holographic lens. The holographic lens was designed to circularize the laser diode beam, correct scanning beam aberrations, and reduce positioning error caused by mode hopping of a laser diode. In fabricating the holographic lens, chromatic aberration caused by the difference between the wavelength used for fabrication and that used for operation was successfully corrected by the use of plano-convex and plano-concave lenses. The lensless holographic scanner was found to have a scanning beam diameter of 170 um for a scanning width of 220 mm.