Abstract: Systems and methods for steering a complex, spatially-modulated incident beam of coherent light to gain access to data locations in a holographic memory cell (HMC). One of the systems includes: (1) a reflective element, locatable proximate a first focal plane of the incident beam, (2) a rotational steering mechanism, coupled to the reflective element, that orients the reflective element according to a desired rotational angle to steer the incident beam in a desired direction and (3) a refractive element that refracts the beam reflected from the reflective element to create a second focal plane for the beam, the HMC locatable proximate the second focal plane to receive the beam at a location thereon that is a function of the desired direction.

Abstract: A side-polished fiber/overlay waveguide architecture and process for non-invasively implementing an optical amplifier are provided for an optical communications system. A "channel" overlay waveguide is employed to constrain for amplification optical energy evanescently coupled to the overlay waveguide from the side-polished optical fiber. One of two amplification methods can be employed. The first involves inducing stimulated emission with the overlay waveguide and the second uses a second order, non-linear frequency conversion to down-convert a high-power, short-wavelength pump signal into the waveguide to amplify the optical energy coupled thereto. Amplification of optical energy in the channel overlay waveguide can be established within a single beat length of evanescent removal to evanescent return of the optical energy to the side-polished fiber optic.

Abstract: Used as a propagation function is a half-plane propagation function which is restricted such that it has a value only within a half plane in a predetermined direction perpendicular to a propagating axis in a plane which is perpendicular to the propagating axis. According to a convolution integration with this function, the wavefront of object light on a hologram surface is determined, whereby hologram data is produced. Thus produced hologram is read out by means of readout light. After the light with a wavefront forming the conjugate image of the object to be viewed is blocked, the image of the object to be viewed is observed.

Abstract: The hologram card generates a hologram image in response to an illumination light beam. The hologram card comprises a substrate of a first plastic material having a first refractive index. The substrate has a contoured surface. The contoured surface is formed to include localized topological features constituting a diffractive optical element. The diffractive optical element is structured to generate a hologram image when illuminated by the illumination light beam. The hologram card also comprises a protective layer of a second plastic material having a second refractive index that differs from the first refractive index by less than 0.2. The protective layer covers the contoured surface of the substrate. The protective layer is chemically bonded to, and directly contacts, at least the topological features constituting the diffractive optical element.

Abstract: The invention relates to a sensor (9) comprising a hologram (17) supported on or within a holographic support medium (10).A species to be detected is reactive with a substance disposed throughout, the sensor (9). Optionally, a chemical reactive with a species to be detected or a specific binding conjugate of a species to be detected is disposed throughout part of or all of the sensor (9).The resulting reaction(s) cause(s) variation(s) in the hologram (17) or holographic support medium (10) which in turn varies one or more optical characteristic(s) of the hologram (17).The variation in the optical characteristic(s) of the hologram (17) and/or the holographic support medium (10), preferably give(s) rise to a wavelength shift in incident radiation. The variation of the optical parameter is related to the species to be detected.The advantages of the sensor are that it is cheap, easy to manufacture and, once calibrated, reliable and robust.

Abstract: This specification discloses a hologram reconstructing apparatus having interference fringe forming means for forming optical interference fringes in conformity with an input signal, information input means for successively inputting different bits of interference fringe information to the interference fringe forming means, and illuminating means for illuminating the interference fringe forming means with a plurality of beams of light differing in wavefront from one another.

Abstract: A diaphragm having an aperture, the size of which is equal to or smaller than .lambda.f/p (.lambda. is the wavelength, p is the imaging resolution, and f is the focal length of an imaging optical system) is arranged on the focal plane of the object space of the imaging optical system, and object light via the aperture is imaged by the imaging optical system. The object light via the imaging optical system and reference light are brought to interference to form interference fringes, and an image of the interference fringes is sensed. Using the hologram sensed in this manner, the image of the object to be sensed is reconstructed by adopting an imaging optical system equivalent to that upon imaging, and setting the positional relationship between the formed hologram and the imaging optical system in correspondence with that between the imaging optical system and the imaging surface upon imaging.

Abstract: An information carrier has at least one diffraction pattern which is formed from microscopically fine relief structures and which, upon being illuminated with coherent light, produces in two spatially separate directions, a first and a second image of an object. The images can be rendered visible on a screen or analysed by means of photodetectors. The two images have strong-light and/or weak-light picture elements and includes a symmetry insofar as a weak-light picture element of the second image can be associated with a strong-light picture element of the first image and vice-versa. Such information carriers are suitable as security elements for documents of all kinds such as, for example, banknotes, passes, identity cards, credit cards, etc., wherein at least a part of the security information is not visible under incoherent illumination conditions.

Abstract: A method for the production of holograms proof against copying and imitation possessing authenticity features, which are copies of a master hologram. In accordance with the invention as a master hologram a hologram of a randomly structured optical element, as for example a diffusion plate, which constitutes the authenticity feature, is recorded and each hologram copy produced from the master hologram is provided with a layer having at least one layer with a color succession and/or the hologram copy produced on a thick light sensitive layer is caused to shrink or to expand.

Abstract: The twin-image elimination apparatus of the present invention comprises (a) a scanning light source for emitting a scanning light beam; (b) an interference device which converts the scanning light beam from the scanning light source into a spherical wave and a plane wave having temporal frequencies different from each other and combines the spherical and plane waves together; (c) a scanner for scanning an object with the combined light beam from the interference device; (d) a photodetector for detecting a scattered wave from the object; (e) a first multiplier which converts an output signal of the photodetector into a cosine-coded holographic information; (f) a second multiplier which converts the output signal of the photodetector into a sine-coded holographic information; and (g) a holographic reconstruction device which converts output signals of the first and second multipliers into a sum signal, in which these output signals are added together with a phase difference of .pi./2+2n.pi.

Abstract: A three-dimensional photo mask is formed from a substrate having a first side and a three-dimensional side. A hologram is provided on the first side of the substrate. The three-dimensional side of the substrate has a photosensitive resist material provided thereon. The hologram includes information that defines features to be imaged onto the photosensitive resist material. A method and a system are disclosed for producing the three-dimensional mask.

Abstract: A hologram which contains the record of a parallel bar-shaped pattern, like a bar code pattern, and which can be read with a single light-receiving element of simple structure with fewer restrictions on the installation position of the light-receiving element and with a minimal lowering in the read accuracy even if the light-receiving element is disposed a little out-of-position. Also disclosed is a method of reading such a hologram. A hologram is recorded in a region that extends in a direction intersecting each bar of a reconstructed bar-shaped pattern and that is not shorter than the length of the reconstructed bar-shaped pattern at least in the above-described direction. Alternatively, the hologram is recorded in a stripe region elongated at the above-described direction.

Abstract: A three-dimensional image display device which comprises a holographic plate having a plurality of holograms divided in correspondence with rotational angles, the holographic plate being exposed so that when light is irradiated, each of the holograms forms a point image at a different position in a depth direction of the holographic plate; a drive unit for rotating the holographic plate; a light irradiating unit including a plurality of light sources arranged substantially in a straight line so that the light sources are kept at substantially equal distances from the holographic plate, for irradiating the holographic plate with light from the light sources; and a controller for controlling the drive unit and lighting operations of the plurality of light sources of the light irradiating unit in accordance with a signal indicative of a three-dimensional image to be displayed so as to control lighting of a plurality of point images formed in a three-dimensional space, whereby a three-dimensional image can be obt

Abstract: A reflecting type liquid crystal display apparatus which can prevent an unnecessary rotation of the plane of polarization in a polarizing prism. The apparatus has: a reflecting type liquid crystal device for changing a polarizing state in accordance with an image, thereby reflecting an incident light; and a polarizing prism 50 for emitting the light of a predetermined polarized component in the incident light from a light source at a surface of polarization operation, for inputting the emitted light into the reflecting type liquid crystal device, for emitting the light of a predetermined polarized component in the incident light from the reflecting type liquid crystal device, thereby obtaining a projection image.

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: An optical device for receiving incident light having a minimum wavelength, and for producing a resultant light containing an optical image. The device includes a first material having a first index of refraction and a surface embossed with an optical interference pattern, and a second material having a second index of refraction deposited onto the embossed surface of the first material. The depth of deposition is at least equal to three quarters of the minimum wavelength component of the incident light within the second material.

Abstract: A displayer for use in a computer comprising a main body, a CRT mounted in the main body and generating an image in an electromagnetic beam, a pair of holograms for projecting the image from the CRT, the holograms mounted in the main body, and a screen for displaying the image projected by the holograms thereon, the screen mounted at a position at which the image is last projected by the holograms. The present invention provides a displayer which provides advantages in that the harmful electromagnetic waves generated from the CRT does not affect the operator by virtue of the holograms, and a screen of a desired large size is obtained at lower cost.

Abstract: Computer-processed or computer-generated objects can be used to build holograms whose images are close to or straddle the hologram surface. No preliminary or first hologram is required. The hologram is built up from a number of contiguous, small, elemental pieces. Unorthodox views from inside the object are required for the creation of these elements. One method of generating the views employs unique object manipulations. The computational transformations ensure that no singularities arise and that more-or-less conventional modeling and rendering routines can be used. With a second method, a multiplicity of conventional object views are collected. Then, all pixels in these conventional viewplanes are reassigned to new and different locations in the new viewplanes for the elemental views. These methods may be used to build rainbow holograms or full parallax holograms. When properly executed they are visually indistinguishable from other types.

Abstract: A holographic television apparatus is disclosed for detecting and displaying three-dimensional holographic information corresponding to a holographic optical interference pattern. The apparatus includes an image detecting device for successively detecting two-dimensional slices of the three-dimensional holographic optical interference pattern, an image reproduction device for successively reproducing two-dimensional slices of the three-dimensional holographic optical interference pattern, a transmission means connecting the image detection device to the image reproduction device, and an actuation unit for moving the image detection device at predetermined regular intervals in an depth direction normal to the two-dimensional image portions to obtain information with respect to the three-dimensional optical interference pattern at unformly spaced two-dimensional layers thereof corresponding to the displacement intervals.

Abstract: Process for producing a hologram reproducing the image of at least one object. Said process is characterized in that a first recording is made of the image of said object on at least one first holographic recording material in order to obtain a holographic image of said object, followed by developing this first holographic recording material, making a second recording from said holographic image on a second holographic recording material shaped to present at least one concave part turned towards the first holographic recording material, whereby at least one part of said image must be located in the space defined by the two holographic recording materials. The first and second holographic recording materials are combined in such a way that the distance separating them during the second recording is variable. Said second holographic recording material is developed and then used in the same configuration in order to play back the image of the object.

Abstract: A holographic optical system includes a hologram which is located at an instrument panel so as to reflect or transmit an image from a source located off the panel. The image is redirected only to an area at which the viewer may observe the image and is not directed to other areas so as to prevent unwanted reflections and glare such as where the instrument panel is within an aircraft cockpit.