Abstract: An exposure apparatus for reproducing a mask pattern onto a photo-sensitive surface of a substrate uses holographic techniques. The apparatus includes support for holding a hologram recording plate at a predetermined position during both a recording operation and a reconstructing operation. A first illuminating optical system introduces a light beam from a coherent light source to a mask and irradiates a subject beam produced from the mask into the recording plate. A second illuminating optical system irradiates the light beam from a coherent light source as a reference beam into the recording plate, a carrier apparatus disposes during the reconstructing operation, a substrate at the position of the mask, in place of the mask. A third illuminating optical system for irradiates a conjugate beam with the reference beam into the recording plate, in which a hologram has been formed by the recording operation, to form an image of the hologram on the photo-sensitive surface of the substrate.

Abstract: A system which enables a film, e.g. a photosensitive material film, to be continuously laminated on and delaminated from a surface of a substrate, e.g. a hologram original plate, and allows duplication to be continuously effected. The system includes a film supply part (32) for supplying a film (1), a film laminating part (37) for continuously laminating the supplied film (1) on a film laminating substrate (35), a film delaminating part (37') for continuously delaminating the film from the substrate (35), and a film take-up part (43) for taking up the delaminated film. In the system, no air bubbles are trapped when the film (1) is laminated on the substrate (35), and no peel unevenness, e.g. undesired line, occurs when the film (1) is delaminated from the substrate (35). The system is suitable for use in a hologram duplicating apparatus, a dimple relief pattern duplicating apparatus, a microscopic test sample preparing apparatus, etc.

Abstract: A product, method, and apparatus are provided for making a stereoscopic hologram from a series of two-dimensional views of an object. The two-dimensional views are obtained from, for example, computer analysis of scans taken by standard medical diagnostic equipment. The views are reproduced on an LCD screen, and the screen then serves as the modulator of the holographic object beam. An exposure of each view is sequentially made on a different section of a holographic recording medium, which may be, for example, a photopolymer placed on a substrate. As the observer views the finished product, each eye looks at a different section of the hologram, thus providing a stereoscopic effect.

Abstract: A method and apparatus for making holograms includes a technique for exposing a film substrate or other light-sensitive medium to consecutive two dimensional images, together representative of a physical three-dimensional system, to generate a three dimensional hologram of the physical system. Low beam ratios are employed to superimpose multiple (20-300) images on the substrate. Each image is relatively weak, but the combination of the series of weak images ultimately appears as a single clearly defined hologram.

Abstract: A modulator apparatus for modulating arrays of input data V.sub.in to be stored in a holographic recording medium is disclosed wherein the final output data array V.sub.out has frequent transitions from light to dark and from dark to light in either dimension across the data page and has the total amount of illuminated regions throughout the entire data page held constant. These two constraints are achieved by a first set of control arrays obtained from two fixed sets of m.times.n binary arrays {A.sub.0, A.sub.1, . . . , A.sub.n } and {B.sub.0, B.sub.1, . . . , B.sub.m } which in turn are obtained from fixed sets of binary control vectors {a.sub.0, a.sub.1, . . . , a.sub.n }, {b.sub.0, b.sub.1, . . . , b.sub.m }, respectively. The control vectors a.sub.0, a.sub.1, . . . , a.sub.n are any n+1 fixed elements of the inverse mapping, .phi..sup.-1 (C.sub.1), of the (t-2) error-correcting code C.sub.1 of length m. The control vectors b.sub.0, b.sub.1, . . . , b.sub.

Abstract: An apparatus is disclosed for changing the scale of a pattern printed from a total internal reflection hologram into a photosensitive layer, which apparatus includes means for reconstructing an image from said total internal reflection hologram by illuminating said total internal reflection hologram with a scanning beam and means for moving at least one of the hologram and photosensitive layer such that the magnitude of movement of the hologram relative to the photosensitive layer is equal to that of the scanning beam multiplied by the change of scale required and such that if said change of scale is a magnification the direction of said movement of the hologram relative to the photosensitive layer is the same as that of the scanning beam whereas if said change of scale is a demagnification then the direction of said movement of the hologram relative to the photosensitive layer is opposite to that of the scanning beam, and optionally comprising also means for increasing or reducing the convergence or divergen

Abstract: A photosensitive optical body is exposed by a diverging three-dimensional standing wave interference pattern generated by a holographic projector system. The projector system, using binary optics, creates a diverging lattice of hexagonal or square rod-like intensity maxima extending through the optical body. After the standing wave image is recorded and fixed, the optical body will contain a honeycomb-like grid or pattern that will cause either an absorption or a refractive index modulation effect on light that differs in incidence to the direction of normal propagation through the created channels to a focus or convergence point. This produces either a volume-absorption hologram or a volume-phase hologram (transmittance function modulated by the permittivity [index of refraction]) with such properties as depth of focus, high resolution, and a one-way (directional perspective) and anti-glare effect with reduced diffraction.

Abstract: In a method for mitigating cross-talk in high-efficiency, angle-multiplexed holograms stored in photorefractive media, a plurality of uniformly low-efficiency holograms are first stored within a common holographic storage medium and then simultaneously exposed to a like plurality of mutually incoherent reference beams. Each reference beam effects enhancement of its corresponding hologram so as to increase the level thereof while also minimizing cross-talk between holograms.

Abstract: A method for the manufacture of TIR holograms includes the division of an input laser beam into an object beam and a reference beam, the direction of the beams to a holographic recording layer so that the object beam is incident on a surface of the holographic recording layer following transmission through an object mask, so that the reference beam is incident on the other surface of the holographic recording layer at an angle such that following passage through the holographic recording layer it is totally internally reflected back into the holographic recording layer and so that the two beams are superposed at the holographic recording layer, and the displacement of the input laser beam causing the object and reference beams to traverse together the holographic recording layer. The method is especially useful for obtaining a high uniformity of exposure of the holographic recording layer.

Abstract: A Bragg reflection filter wavemeter is used to measure transverse holographic gratings and optical fibers and utilizes a first interferometer which is always fixed with respect to the optical fiber and a second adjustable interferometer. The optical fiber and first interferometer are mounted on a translating support while the second interferometer includes a pair of angularly adjustable mirrors for changing the angle at which the object and reference beams thereof intersect the fiber. Since the fiber is mounted on a movable support, the position of the support can be continually adjustable so that the reference and object beams always intersect the fiber at the same point, regardless of the angle assumed by the reflecting mirrors. The resulting interference patterns are projected by an objective lens to the far field in which a linear scanning, photodiode array is moved.

Abstract: An exposure apparatus for reproducing a mask pattern onto a photo-sensitive surface of a substrate using holographic techniques.

Abstract: A hologram recording method wherein a transparent member for introducing a light beam into a recording material is designed so that the transparent member and the recording film can be uniformly brought into close contact with each other through an index matching liquid without damaging the recording film, and it is possible to stably carry out uniform and continuous exposure without failure of recording nor occurrence of unnecessary interference fringes. Also disclosed is a recorded hologram. A transparent member (3) is disposed at one surface of a recording film (2). A surface (5) of the transparent member (3) that is brought into close contact with the recording film (2) is convexly curved only in the direction of feed of the recording film (2). In addition, the space between the contact surface (5) and the recording film (2) is filled with an index matching liquid (4) so that the recording film (2) is brought into close contact with the transparent member (3) through the index matching liquid (4).

Abstract: A package for a holographic storage media (10) is provided that utilizes a slide tray (43) for containing a plurality of slides (102). Each of the slides (102) is comprised of an opaque casing (110), which is operable to hold a sandwich structure (120). The sandwich structure (120) has a gripping mechanism (122) disposed on the edge thereof for allowing the structure (120) to be reciprocated within the jacket (110) for extraction thereof and reinsertion thereof. A gripping arm (156) is operable to attach to a gripping member (124) on a gripping mechanism (122) attached to the slide (102) to extract the slide (102) and place it into a holder (148). The holder (148) is then operable to receive the slide (102) and dispose it in a holographic storage system. The slide (102) can then be written to by interfering a data beam and a reference beam in a predetermined storage location (54) and then the slide again placed into the jacket (110).

Abstract: The method involves directing first and second separate illuminating beams towards a photosensitive film from separate fixed apparent beam source positions respectively in such a manner that the beams are caused to overlap at the point of incidence at the photosensitive film. Stationary interference fringes are generated and the beams are caused to scan in a raster type pattern over the photosensitive film in such a manner whereby overlapping of the beams is maintained throughout the exposure of the film. The apparatus in one embodiment involves the generation of a third illuminating beam which is used to control means to control an associated scanner to effect synchronised movement of the second beam with the first beam. A further embodiment involves memorising the scanning movement of beam in a memory and using the memorised scanning pattern to control the scanner to maintain beam overlap.

Abstract: This specification discloses a method of making a hologram imaged substantially without aberrations during the use when the wavelength of a light during the making differs from the wavelength of a light during the use and having high diffraction efficiency. In order to eliminate any aberration occuring when the hologram is used in a light beam of a different wavelength and to obtain high diffraction efficiency, a making light beam is caused to enter a predetermined coaxial optical system from outside the axis thereof to impart a suitable aberration, and a hologram is formed on a hologram sensitive material by the making light beam.

Abstract: A dynamic holographic display has an array of reflective surfaces formed on cantilever structures substantially parallel to the surface of a substrate, such as a silicon wafer. A holographic image is formed by controlling electrical currents passed through the cantilever structures to position the reflective surfaces of the cells in the array so the topography forms a hologram, and reflected light interferes to form a holographic image. In a preferred embodiment, control is by computer and positions of reflective surfaces are determined by calculation from dimensional data available to the control computer.

Abstract: A holographic apparatus for continually sensing, transmitting and reconstructing a three-dimensional image including a device for receiving a holographic interference pattern such as a video camera, a device for creating a holographic interference pattern on the receiving device, a device for focusing the interference pattern on the input of the receiving device, a device for transmitting the received holographic interference pattern including a device such as a computer, a device for converting the transmitted holographic interference pattern to a holographic interference pattern which is representative of the three-dimensional image such as an LCD and a source of coherent light illuminating the holographic interference pattern on the converting means to reconstruct the three-dimensional image.

Abstract: A reflecting master hologram is illuminated with collimated coherent beams at an incident angle to provide regular reflected beams and diffracted beams. The regular reflected beams and the diffracted beams are directed to a reflective photoresist plate at the same angles as those at which they are, respectively, reflected by the reflecting master hologram so as to form an intensity pattern, i.e. a bright and dark pattern, of interference fringes on the reflective photoresist plate. The exposed photoresist plate is developed and etched to form a reflective hologram on the plate.

Abstract: A computer-generated hologram recording apparatus includes a diffraction image generator which receives an input image signal representing an object and computes a corresponding diffraction pattern with a first sampling density. An interpolation processor is connected to the diffraction image generator via an intermediate page memory. The interpolation processor subjects the diffraction pattern to the interpolation process to create an interpolated diffraction pattern with an increased second sampling density. An interference pattern generator is connected to the interpolation processor to compute an interference caused pattern between the interpolated diffraction pattern and a reference wave by converting amplitude and phase distributions of the input image signal into the intensity distribution. A multi-beam scan printing apparatus records the interference pattern on a previously selected recording medium for later reproduction by use of white light.

Abstract: The present invention relates to a novel source array comprising a plurality of sources of optical illumination that are at once both individually coherent and mutually incoherent. A primary application of such a source array is to provide the requisite optical source beams in a novel architecture and associated apparatus for the development of highly multiplexed photonic interconnection networks and holographic optical elements with maximum optical throughput efficiency and minimum interchannel crosstalk, based on parallel incoherent/coherent holographic recording and readout principles that are described herein. In one embodiment, the source array is configured from a plurality of coherent sources of illumination; in a second embodiment, a single source of coherent illumination is expanded to illuminate a phase modulator array, within which each separate phase modulator is driven at a distinct oscillation frequency such that the set of resultant modulated beams exhibits mutual incoherence.

Abstract: A hologram exposure system for simultaneously exposing a plurality of holograms in a holographic recording layer, including first optical elements for providing a first reference beam and a first object beam that interfere in the holographic recording layer and are coherently matched relative to each other, and second optical elements for providing a second reference beam and a second object beam that interfere in the holographic recording layer and are coherently matched relative to each other but are coherently mismatched relative to the first reference and object beams, whereby the crosstalk holograms formed by interference of (1) the first reference beam with the second object beam, (2) the first object beam with the second reference beam, (3) the first object beam with the second object beam, and (4) the first reference beam with the second reference have reduced efficiencies.

Abstract: Light emitted from a coherent light source undergoes fine adjustment of its polarizing direction by a polarizing device and is directed to a liquid crystal device through a collimating optical system. The polarizing device is capable of fine-adjusting the polarizing direction in accordance with the wavelength of the incident light, thereby providing a high contrast ratio. When an image is recorded by holography using such a liquid crystal spacial light modulator, it is possible to obtain an image of high quality.

Abstract: An apparatus 10 for exposing a curved grating pattern of monochromatic light on a photoresist coated semiconductor wafer 12 includes an argon gas laser 14 that outputs a monochromatic light beam 16. This monochromatic light beam 16 is filtered and collimated to produce a monochromatic light beam with a planar wavefront 24. A portion of this planar wavefront passes through a cylindrical lens array 26 and a first baffle slit 30, producing multiple cylindrical wavefront 34 that is incident upon a hypotenuse face 38 of a right angle prism 40. Another portion of the planar wavefront passes through a second baffle slit 32, producing a smaller planar wavefront 36 that is also incident upon the hypotenuse face 38 of the right angle prism 40. A destructive interference between a reflected multiple cylindrical wavefront 92 and a direct planar wavefront 90 inside the prism 40 produces a curved grating pattern of monochromatic light on an adjacent prism face 42.

Abstract: An exposure apparatus capable of making exposure for concentric circular periodic grating is provided with a quarter-wave plate (4), an ND filter (8a) having step-wisely different transmissions with boundaries of circle or a group of circles, an axially symmetric-shaped patterning mask (8b), an interference lens (9), before a sample substrate (10) having a photosensitive film (11). The interference lens (9) has a form of rotation symmetry with respect to optical axis (9L), and its incident surface (9P) is a flat plane, and its exit surface (9S) is a surface of revolution which is close to a circular cone.

Abstract: An image of an object embedded in a diffusing medium is formed by propagating a coherent or equivalent light pulse through the diffusing medium and applying a reference pulse so as to gate precisely the first emerging light transmitted through the diffusing medium. An ultra-short pulse, having a duration on the order of 150 fs, insures that only the first emerging light is used to form a hologram. Instability in the diffusing medium, which may be inherent therein, as is the case with living tissue, or artificially induced therein, such as by vibrating the specimen, ensures that a subsequent hologram has a different background noise and speckle pattern. Integration of such holograms causes the background noise to average out, but time-invariant features, such as the object being imaged, become increasingly more visible as more holograms are integrated.

Abstract: A hologram exposure apparatus for and method of obtaining a hologram using a photoresist for an in-line type interferometer wherein a photoresist substrate is detachably mounted on a substrate rotating device. A concentric pattern of a hologram from a source of light is projected onto the photoresist on the substrate mounted on the substrate rotating device while rotating the substrate and moving a projecting device in a direction at right angles with the rotary shaft of the photoresist substrate.

Abstract: A photosensitive element 46 absorbs at least a portion of an incident write beam 40, causing a spatially varying electric field to be applied across a layer of a ferroelectric liquid crystal (FLC) 48, thereby forming a pattern of local polarizations corresponding to the spatially varying electric field. In one embodiment, a signal beam is modulated with a phase variation characteristic of a particular aberrator. The signal beam is then combined with a substantially plane wave reference beam to form interference fringes. These interference fringes are directed as a write beam onto photosensitive layer 46, forming a hologram in FLC layer 48 which can be read optically. An incident beam of light can be diffracted by a hologram formed in the FLC layer, thereby modulating the incident beam of light with the phase variations comprising the hologram.

Abstract: A holographic recording of the interference between an object laser beam and a reference laser beam is used to combine the amplitudes of multiple laser beams which are conjugates of the reference beam into a single laser beam which is conjugate of the object beam. An optical device in the form of a prism has an entrance face with a diffusion surface, and an exit face with a light sensitive recording medium. An object beam incident on the diffusion surface is scattered over the recording medium, in interference with a reference beam simultaneously incident at an angle .theta. onto the same medium. Multiple beams, conjugate to the reference beam, incident at angles .theta..+-.4.degree. on the hologram thus created on the recording medium are diffracted by the hologram and caused to combine at the diffusion surface to form a signal output beam, conjugate to the original object beam and having an amplitude which is proportional to the sum of the separate amplitudes of the combined beams.

Abstract: Apparatus and method for storing holographic synthesized information for reflection integral Bragg holograms, free of the limitations of dispersing elements (such as unilateral diffusing screens, conventional lenticular screens and Fresnel lenses), multiple reference beams, mirrorized indexing or other similar materials or techniques. These holograms accurately satisfy Bragg's condition, provide an expanded (and essentially normal) vertical viewing range and can be displayed both flat (in which case the image is behind the film plane) or concave towards the viewer (in which case the image is in front of the film plane). Flat and curved holograms can be combined together. The final holographic images are produced directly from motion picture film, without intermediate transfer prints as required by the prior art. All are front illuminated. By curving the developed hologram for viewing a high definition projection image is obtained.

Abstract: A hologram exposure system that includes a spherically curved mirror surface positioned adjacent a substrate/hologram assembly that includes a spherically curved hologram recording layer supported by a spherically curved substrate surface, wherein the spherically curved mirror surface is concentric with the spherically curved substrate surface. A first rotating means provides for rotation of the curved mirror surface about a first axis that passes through (a) the center of curvature of the spherically curved substrate surface that supports the hologram recording layer, and (b) a point on the hologram recording layer that allows for convenient rotation about the first axis; and a second rotating means provides for rotation of the curved mirror surface about a second axis that is orthogonal to the first axis and intersects the first axis at the center of curvature of the substrate surface that supports the hologram recording layer.

Abstract: A holographic apparatus for continually sensing, transmitting and reconstructing a three-dimensional image including a device for receiving a holographic interference pattern, a device for creating a holographic interference pattern on the receiving device, a device for transmitting the received holographic interference pattern, a device for converting the transmitted holographic interference pattern to a holographic interference pattern which is representative of the three-dimensional image and a source of coherent light illuminating the holographic interference pattern on the converting means to reconstruct the three-dimensional image.

Abstract: A dynamic holographic display has an array of reflective surfaces formed on cantilever structures substantially parallel to the surface of a substrate, such as a silicon wafer. A holographic image is formed by controlling electrical currents passed through the cantilever structures to position the reflective surfaces of the cells in the array so the topography forms a hologram, and reflected light interferes to form a holographic image. In a preferred embodiment, control is by computer and positions of reflective surfaces are determined by calculation from dimensional data available to the control computer.

Abstract: A holographic camera assembly includes a portable, light-tight housing having a removable cover to access the interior thereof. Camera components are positioned upon an optics tray within the housing which is vibrationally isolated from the housing. The film is releasably mounted within a frame and includes a releasable film casing protecting the film from ambient light. The frame, including the film and casing, is releasably mounted upon a rotatable platform in one corner of the tray and a three-dimensional object of one's choice is positioned therebehind. The cover is replaced upon the housing making the interior thereof light-tight. Means operable at a control panel externally of the housing selectively raise and lower the casing about the film. When in the fully raised position, a coherent light beam is allowed to travel along a fixed path (by action of a timed shutter mechanism) to pass through the film to strike the object. The reflection of light by the object back to the film creates the hologram.

Abstract: A pulsed laser provided a pulsed incident beam which impinges a recording assembly which includes a glass substrate and a recording film adhered thereto. The pulse can be singular or multiple. In either event, the duration of each pulse of light is controlled in such a fashion so that the pulse is long enough to enable it to reflect off of a reflecting element to thereby produce a primary reflected beam. In the recording film, the primary reflected beam can interfere with the incident beam to produce the interference pattern in the film. However, the pulse is not of such a duration to allow a noise reflected beam, such as one from a glass-air interface, to pass through the recording film and interfere with the incident beam or primary reflected beam while those beams are still present. Thereby, noise holograms which might otherwise be recorded in the film are precluded while allowing the primary hologram to be recorded.

Abstract: An apparatus for recording Lippman holographic mirrors comprises an exposing volume optically coupled on one side with an index-matching fluid to the holographic material to be recorded. The volume is exposed on an adjacent side to a light beam expanded in one direction into a plane of light whose projection on the volume is a line. The line of light and the holographic material are moved relative to each other on an interrupted or a continuous basis to expose the holographic material.