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: A holographic recording of the interference between an object laser beam and a reference laser beam is used to combine the amplitudes of multiple input laser beams which are conjugates of the reference beam, into a single output laser beam which is a conjugate of the object beam. An optical device in the form of a trapezoidal prism has an entrance top face with a diffusion surface, and an exit base face with a holographic recording made on a light sensitive recording medium of an interference pattern of an object beam incident on the diffusion surface and scattered over the recording medium, in interference with a reference beam simultaneously incident to a side of the prism onto the same medium.

Abstract: A method and apparatus for the collation or fine comparison of closely related images made with coherent light, such as those that may arise in holographic interferometry, in holo-photoelasticity, or in speckle interferometry.

Abstract: A camera for use in holography comprises a source of coherent radiation (55), a beam splitter (55,56) for splitting radiation from said source into a reference and a recording beam, a film holder (62) for holding a recording medium (61), means for directing the reference beam on to the recording medium, means for directing the recording beam on to an object and means for combining the recording beam after reflection from the object with the reference beam to form a hologram within the recording medium.

Abstract: In an imaging process and system by transillumination of a medium illuminated by transparency by a beam, an acoustic transducer emits an acoustic wave in the medium which interferes with the beam. The frequency of the light passing through the medium is then shifted from the value of the frequency of the acoustic wave. A collimating device whose object focus is located at the intersection of the acoustic wave and the light beam collects the light diffused by the medium.

Abstract: Holographic optical elements relatively free of unwanted, secondary fringes are produced using light having a limited coherence. A photosensitive material of a predetermined thickness records the interference between two beams of light. The mutual coherence of the two illumination beams is sufficiently great to form high contrast interference fringes within some portion of the photosensitive medium. The mutual coherence is limited to prevent the formation of high contrast interference with reflections from the various parts of the construction optics. The two illumination beams may be incident from opposite sides of the photosensitive medium forming a reflection holographic optical element or from the same side of the photosensitive medium forming a transmission holographic optical element. A laser generates the first illumination beam. Control of the mutual coherence may be by passing the first illumination beam through a moving diffuser plate or by varying the wavelength of the laser during the exposure.

Abstract: The present invention relates to 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. This scheme further provides for arbitrarily weighted and independent interconnections, which are of potential importance in the development of neuro-optical computers, as well as photonic interconnection networks and multiplexed holographic optical elements. In addition, the extremely difficult problem of copying the contents of a three-dimensional holographic storage device in one step is soluble by utilization of the architectural principles and specified apparatus that are key features of this invention.

Abstract: Improved optical holographic apparatuses are disclosed for making white light viewable rainbow holograms in one step utilizing concave mirror optics. On-axis and off-axis configurations are presented for holography of real objects and for reduced image holography of a real image projection from a laser transmission hologram. An optical apparatus and curved recording devices are devised to reduce and/or eliminate certain aberrations introduced by the concave mirror. To yield a wide holographic field of view at low cost, small diameter mirrors are employed in two alternative devices for replacing a single concave mirror in the various embodiments. Two methods are then presented to obtain reduced image size one-step rainbow holograms from a full size object or holographic image.

Abstract: This invention relates to a method and apparatus for exposing a photosensitive film on a holographic plate to fabricate a reflective holographic optical element. The apparatus incorporates compensating means which are adapted to compensate for the effects of refractive index shift of the film due to refractive index variations during the exposure process. In one form of the apparatus, a hologram-mirror arrangement is placed on a table on an accurately controlled stepper motor rotating stage so that the table is progressively tilted. In an alternative arrangement the angle of the exposing radiation beam is changed and directed on to the stationary hologram-mirror arrangement. Where a tuneable holographic filter is required where the exposure angle varies over the hologram aperture angular shift is achieved by simple lateral and linear shift of the hologram. The compensating means can also comprise an arrangement for progressively changing the wavelength of the exposing radiation beam.

Abstract: A method of using the classic principles of moire patterns and holography to provide defect analysis of variable sensitivity on structures of various sizes, including large aircraft. By taking several holograms (usually a series of four) of the structure which has been illuminated with dual (or multiple) beams of coherent illumination (e.g. laser), each hologram will record an image of the test object which includes an interferometric fringe pattern on the surface. The spacing and orientation of the fringe pattern can be varied by the arrangement and nature of the dual illumination beams.

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: A new class of sensitizers for photopolymerizable compositions is disclosed derived from cyclic ketones and tricyclic aminoaldehydes. A preferred compound is cyclopentanone, 2.

Abstract: A laser light show device and method produces a surface projected or suspended holographic image, and includes multiple image projectors. One image projector provides the object image information representing the primary subject. For surface projections, additional background image projectors provide background image information generated using a wobbler plate-reflected beam diffracted through a spherical lens, a beam unidimensionally diffracted through a rotating cylindrical amorphic dipolyhedral lens, and a beam diffracted through multiple diffraction gratings. A suspended holographic image is produced by parabolically focusing multiple images projected onto a spherical image screen.

Abstract: Holographic optical elements relatively free of unwanted, secondary fringes are produced by passing the light beam from a laser through a rotating diffusing plate to generate a beam of light having a very limited coherence length and a spatial coherence which changes over a period of time. A photographic emulsion having a mirror supported on its reverse side is illuminated by the beam and interference occurs between this primary illumination and illumination reflected from the mirror, creating fringes. No other interference fringes are formed because of the lack of coherence between secondary reflections and other rays of the incident beam. The rotation of the diffusion plate time averages out speckle patterns which would otherwise occur. Alternatively, the illuminating beam has a high degree of spatial coherence but its temporal coherence is reduced and varied over a period of time by changing the wavelength of a tunable-dye laser.

Abstract: A fiber optic point source is utilized to generate a first wavefront which is intersected with a second wavefront to form a desired interference pattern in a recording medium. The point source is moved relative to the recording medium during exposure in order to reduce multiple order scattering noise, and a feedback monitoring system permits determination of portions of the recording medium requiring increased exposure.

Abstract: A fiber optic point source is utilized to generate a first wavefront which is intersected with a second wavefront to form a desired interference pattern in a recording medium. The point source is moved relative to the recording medium during exposure in order to reduce multiple order scattering noise, and to provide a relatively large translational motion which is gradual and generally follows an angular scanning motion of the fiber optic point source.