Abstract: A rangefinder performs highly accurate 3D measurement without being affected by any variation in intensity of projected light. A light source for projecting light onto an object is provided with a light receiver for detecting the intensity of the projected light. The intensity of a reflected part of the projected light, which has been captured by a camera as an image, is corrected using the light intensity, which has been detected by the light receiver, as correction information. And based on this corrected image, a distance calculator produces a range image. Thus, even if the intensity of the projected light has changed, a corresponding variation in intensity of the reflected light image can be compensated for.

Abstract: There is described an image-recording medium and an image-reading method, which make it possible to improve reading accuracy of information by avoiding duplication of an optical variable image with the information. The image-recording medium includes a substrate, an image-receiving layer provided on the substrate and an optical variable layer provided on the substrate, wherein at least a part of the optical variable layer includes an optical variable image, and the optical variable image is formed in a manner such that the optical variable image, overlapping with an image recorded on the image-receiving layer, emerges in a first direction, while the optical variable image, overlapping with an image recorded on the image-receiving layer, does not emerge in a second direction.

Abstract: A holographic microscope is described along with a method for numerically reconstructing a holographic image. The method uses a coordinate transformation of the Kirchhoff-Helmholtz equation to remove the non-linear component from the phase factor. The intensity distribution in the transformed coordinate system is then interpolated on an equidistant point grid and Fast-Fourier-Transforms are used to compute the result.

Abstract: A system for illumination of a hologram includes a deflection mirror to direct light from a moving light source to illuminate the hologram, and a heliostat for tracking the moving light source and positioning the deflection mirror to direct light therefrom to illuminate the hologram. Such as system is optimized for illuminating outdoor holographic displays while still providing a desirable light source and illumination angle, and doing so efficiently and at low cost.

Abstract: A system and method are disclosed for producing and displaying a one-step, edge-lit hologram. For production, an object beam and an edge-lit reference beam are directed at holographic recording material and to interfere with one another. The holographic recording material and the object beam and edge-lit reference beam are then translated with respect to one another. The translation successively exposes multiple portions of the holographic recording material to the interference of the object beam and the edge-lit reference beam to record an edge-lit hologram on the holographic recording material. In one embodiment, the holographic recording material is moved while the object beam and the edge-lit reference beam remain generally stationary. In another embodiment, the object beam and the edge-lit reference beam move in unison with each other while the holographic recording material remains generally stationary.

Abstract: A method of advertising on a motor vehicle having a substantially transparent window including steps of providing a holographic film with a holographic image, and adhering the holographic film to the window, where the holographic image is substantially transparent to an operator of the motor vehicle from within the motor vehicle so that operation of the motor vehicle is not impeded, but the holographic image is visible to an observer outside the motor vehicle. The present method may also include the steps of applying a transparent adhesive to the holographic film and/or the window. The holographic image may be a product name, a corporate name and/or a corporate logo. The motor vehicle may be a motorsport vehicle adapted to be raced in a race track with at least one other vehicle. The holographic image may be a numeral that distinguishes the motorsport vehicle but is preferably a sponsor advertisement that includes a product name, a corporate name and/or a corporate logo.

Abstract: In a holographic screen for laser front projection, of at least one or more laser wavelengths that selectively back-scatter the incident spectrally narrow-band laser radiation in a predetermined solid angle and simultaneously highly absorbs the disturbing spectrally broad-band ambient light, it is proposed that it have at least one holographic volume grating that is optically coupled to a light absorber.

Abstract: An optical display apparatus is provided that can utilize a low intensity point light source and that requires a small physical profile. The optical display apparatus comprises an image display apparatus including at least one point light source to form an image to be displayed for viewing, a hologram screen that defracts and reflects light from the point light source, and an imaging optical system arranged to adjust a focus in one direction of the image so that the point light source of the optical display apparatus is focused to a line on the hologram screen. The optical display apparatus reconstructs and images the image displayed on the image display apparatus on a virtual display plane.

Abstract: A transmission hologram allowing an illuminating light source for holographic reconstruction to be placed behind the hologram, i.e. on the side opposite to the viewing side, and permitting reconstruction of an image that is bright and clear and has low chromatic dispersion, which is the feature of the reflection type volume hologram. A transmissively viewable reflection hologram has a semitransparent reflecting mirror or a semitransparent reflecting layer placed at either side of a reflection type volume hologram member. The semitransparent reflecting mirror or the semitransparent reflecting layer is integral with or separate from the reflection type volume hologram member.

Abstract: An optical member 7 is bonded, at its rear side 7b, to a holographic stereogram 6. The front side 7a of the optical member 7 consists of parallel triangular prisms. Illumination light 9 is applied to the front surface 7a of the optical member 7 at a predetermined angle of, for example, 60°. The optical member 7 is made of, for example, optical glass or transparent plastic. Each triangular prism has an incidence surface 8, to which the illumination light is applied at right angles. The illumination light is applied to the interface 22 between the optical member 7 and the holographic stereogram 6, at an incidence angle &thgr; of, for example, 60°, thereby to suppress surface reflection of the illumination light 9 at the interface 22.

Abstract: An image processing system and method visually documents and displays the in-vivo location from which a biopsy specimen was extracted, by processing pre-biopsy and post-biopsy images. A composite image is created which visually emphasizes differences between the pre-biopsy and post-biopsy images. Preferably three-dimensional, digitized images, displayable in various projections, are stored for archival purposes on computer readable media. An image processor preferably exploits an optical correlator to register the pre-biopsy and post-biopsy images accurately. The images are then compared, voxel-by-voxel, to detect differences between pre-biopsy and post-biopsy images. The composite image is displayed with synthetic colors, synthetic icons, or other visual clues to emphasize probable in-vivo biopsy locations.

Abstract: A method of advertising on a motor vehicle having a substantially transparent window including steps of providing a holographic film with a holographic image, and adhering the holographic film to the window, where the holographic image is substantially transparent to an operator of the motor vehicle from within the motor vehicle so that operation of the motor vehicle is not impeded, but the holographic image is visible to an observer outside the motor vehicle. The present method may also include the steps of applying a transparent adhesive to the holographic film and/or the window. The holographic image may be a product name, a corporate name and/or a corporate logo. The motor vehicle may be a motorsport vehicle adapted to be raced in a race track with at least one other vehicle. The holographic image may be a numeral that distinguishes the motorsport vehicle but is preferably a sponsor advertisement that includes a product name, a corporate name and/or a corporate logo.

Abstract: A description is provided of an optical information recording and reproducing apparatus employing a holographic memory. The apparatus includes a mask disposed in an optical path of the signal light beam so as to cover a light intensity distribution of the signal light beam incident into the holographic memory at nearly a half portion thereof with respect to the center of the distribution of the zeroth-order diffracted light of the signal light beam. The center of a region of the holographic memory where the signal light beam and the reference light beam intersect with each other, is shifted by a distance substantially equal to twice the distance between peaks of the zeroth-order diffracted light or the first-order diffracted light of the signal light beam.

Abstract: An information medium consists of an essentially circular or polygonal disk having at least two pairs of sides parallel to one another which have the same distance to one another in each pair. To reliably read stored data from such an information medium at high speed, a hologram is disposed on at least one side of the disk at its center or at the intersection of two crossing symmetry lines which can be reconstructed with a reference beam incident to the side at a right angle to a pattern consisting of essentially concentric circles, with the reference beam forming the axis of said pattern.

Abstract: An apparatus and method is disclosed for illuminating an image display with ambient light using holographic techniques. The apparatus includes a pair of holographic optical elements each having a first surface aligned on a common axis so that the first surfaces of each optical element face each other. Each of the first and second optical elements diffracts first bandwidth light. The second holographic optical element, however, diffracts first bandwidth light received on the first surface facing the first surface of the first holographic optical element. The second holographic optical element diffracts first bandwidth light received on its first surface, the diffracted light emerging from the first surface. The first and second holographic optical elements are switchable between inactive and active states. In the inactive state, each of the first and second holographic optical elements transmits substantially all light without substantial alteration.

Abstract: A reference beam telescope, which is also referred to as a relay imaging system for a reference beam, using reflection optics is disclosed. The relay imaging system according to the present invention comprises at least one concave mirror and one convex mirror. A reference beam is reflected at least twice by the concave mirror and once by the convex mirror. The output reference beam is collimated if the input reference beam is collimated. This relay imaging system is used in a holographic storage system to deliver the reference beam to the holographic storage medium. In particular, this system can be used for angular multiplexing in a holographic storage system.

Abstract: A digital holography device, applicable for example to the 3D mapping of objects, is used to determine the complex amplitude of a signal wave coming from an object illuminated by a known illumination wave. For this purpose, the device includes a source for the generation of two mutually coherent waves, the object illumination wave and a reference wave, the two waves having a phase difference &phgr;i(t) that is a function of time. The device also includes a mechanism configured to induce an interference, on a detection device, between the reference wave and the signal wave coming from the object. The detection device enables a temporal sampling of the interference pattern resulting in the acquisition of a number N of interferograms, N being greater than or equal to 2.

Abstract: A system and method for generating a composite display that includes at least one static three dimensional holographic image, and dynamic and/or static two dimensional images. An object hologram includes a three-dimensional object image. A silhouette hologram includes a silhouette image of the object, and can include a diffusion screen. The object hologram overlays the silhouette hologram with the object image substantially aligned with the silhouette image. Static and/or dynamic images can be projected on the diffusion screen or alternative background, forming a composite image that includes dynamic and/or static two-dimensional imagery combined with the static three-dimensional object image. The silhouette image thus provides a background for viewing the object image and occludes the two-dimensional imagery from the view of the object image.

Abstract: Methods of producing holograms to be used in the SYSTEM AND APPARATUS FOR THE RECORDING AND PROJECTION OF IMAGES IN SUBSTANTIALLY 3-DIMENSIONAL FORMAT that is the subject of U.S. Pat. No. 6,224,562.

Abstract: The invention provides a hologram recording or replicating optical system wherein a misalignment-with-time of the center of a laser generated beam is automatically corrected so that the color balance in a color hologram surface, for instance, can be well maintained with no disturbance. In the hologram recording or replicating optical system for irradiating a photosensitive material 20 with a beam from a laser 31 through a pinhole 10, a beam position correcting mechanism 32 and a beam splitter 33 are located in an optical path between the laser 31 and the pinhole 10, and a laser beam position detector 35 is located at a position in an optical path split by the beam splitter 33 and conjugate to the pinhole 10, so that the beam position correcting mechanism 32 can be operated on the basis of a beam position error signal obtained from the laser beam position detector 35 to keep the position of the beam incident on the pinhole 10 always constant.

Abstract: A method and an apparatus for three-dimensional holographic display suitable for moving object display are disclosed. At least one hologram of a display target object is displayed on a display device, and a non-scattered light is irradiated onto the display device to produce a scattered light. Then the scattered light from the display device as an object light of the display target object and the non-scattered light as a reference light are irradiated simultaneously at different incident angles onto a photorefractive medium having a photorefractive effect, and interference fringes generated by the object light and the reference light are recorded in the photorefractive medium. Then, the three-dimensional image is displayed by irradiating only the non-scattered light onto the photorefractive medium so as to reproduce a holographic image corresponding to the interference fringes recorded in the photorefractive medium.

Abstract: A system and method are disclosed for producing and displaying a one-step, edge-lit hologram. For production, an object beam and an edge-lit reference beam are directed at holographic recording material and to interfere with one another. The holographic recording material and the object beam and edge-lit reference beam are then translated with respect to one another. The translation successively exposes multiple portions of the holographic recording material to the interference of the object beam and the edge-lit reference beam to record an edge-lit hologram on the holographic recording material. In one embodiment, the holographic recording material is moved while the object beam and the edge-lit reference beam remain generally stationary. In another embodiment, the object beam and the edge-lit reference beam move in unison with each other while the holographic recording material remains generally stationary.

Abstract: Switchable holographic optical elements (HOEs) can used in systems and methods for projecting three-dimensional images, or for projecting two-dimensional tiled images with increased size and/or resolution. One of the methods may include sequentially displaying first, second, and third color components of a first two-dimensional image at an object plane. The first two dimensional image represents a first slice of a three-dimensional image. As the first, second, and third color components are displayed, first, second and third HOEs may be activated so that the activated first switchable HOE focuses the first color component of the first two-dimensional image onto a first image plane, the activated second switchable HOE focuses the second color component of the first two-dimensional image onto the first image plane, and the wherein the activated third switchable HOE focuses the third color component of the first two-dimensional image onto the first image plane.

Abstract: A method for the numerical reconstruction of digital holograms which allows simultaneously amplitude and quantitative phase contrast imaging. The reconstruction method computes the propagation of the field that would be diffracted by the hologram during a standard hologram reconstruction. The method requires the adjustment of several reconstruction parameters for the definition of a digital replica of the reference wave. When the set-up used for the hologram creation produces phase aberrations, the method includes a digital method for the correction of the phase aberrations. The phase contrast image is quantitative, meaning that the reconstructed phase distribution can be used for quantitative measurements. The method can be used to reconstruct a set of holograms taken in different conditions. The method can be used to reconstruct several images from a single hologram taken with more than one reference waves and/or more than one object waves.

Abstract: The disposable liquid beverage container of the present invention comprises a first compartment for sealably containing a beverage and a second compartment adjacent the first compartment. A barrier having a translucent portion separates the first and second compartments. A light source and an energy source electrically connected to the light source are disposed in the second compartment. A switch activates the light source such that the light source shines through the translucent portion of the barrier and illuminates the beverage disposed in the first compartment of the container. A holographic image embedded in a film attached to an outside of the container is created within the first compartment when the light source is illuminated. Methods are also provided.

Abstract: A method and a compact apparatus to read shift-multiplexed holograms on a storage medium without the need for any lenses, and without the need for moving the storage medium. The shift-multiplexed holograms have centers at different locations. The apparatus can generate an array of diverging spherical waves of reference beams, each for illuminating one of the holograms. Each hologram is read as an image on a detector array by illuminating that hologram with a corresponding diverging spherical wave of reference beam. Different holograms can be read by illuminating the medium with a different diverging spherical reference beam. The diverging beams can be from an array of sources, or can be from switching one source.

Abstract: Scanning sensor scans on a circumference and simultaneously a radiation wave is received by scanning sensor to generate received signal Sm(f). A radiation wave is received by a fixed sensor at a position not changed with respect to the center of a circle with the circumference to generate received signal Sr(f). The received signal Sm(f) is made to interfere with the received signal Sr(f) to acquire an interference signal. The interference signal is detected to obtain measured data E(r,&phgr;) at each point on the circumference. Also, evaluation data V(&phgr;′) is calculated to estimate a direction of the radiation wave based on measured data E(r,&phgr;) at each point.

Abstract: A real-time, dynamic, free space-virtual reality, 3-D image display system which is enabled by using a unique form of Aerogel as the primary display media. A preferred embodiment of this system comprises a 3-D mosaic topographic map which is displayed by fusing four projected hologram images. In this embodiment, 4 holographic images are projected from 4 separate holograms. Each holographic image subtends a quadrant of the 4&pgr; solid angle. By fusing these four holographic images, a static 3-D image such as a featured terrain map would be visible for 360 degrees in the horizontal plane and 180 degrees in the vertical plane. An input, either acquired by 3-D image sensor or generated by computer animation, is first converted into a 2-D computer generated hologram (CGH). This CGH is then downloaded into large liquid crystal (LC) panel. A laser projector illuminates the CGH-filled LC panel and generates and displays a real 3-D image in the Aerogel matrix.

Abstract: An optical interface of a holographic memory system electrically selects one of several optical pathways to store or retrieve an image from a holographic memory by activating liquid crystal polarization rotators and novel liquid crystal gratings. In a preferred embodiment a spatial light modulator, a pixelized readout device (i.e., focal-plane array), a series of polarizing optical components, liquid-crystal polarization rotators, liquid-crystal beam-steering devices, and interconnecting and imaging optics are provided. The parallel interconnection accepts a laser-beam input, divides the beam among multiple paths, imparts a data-bearing spatial signature on a signal beam by means of a spatial light modulator, steers a reference beam by means of liquid-crystal beam-steering devices, and directs the appropriate beams into the recording medium.

Abstract: A method and system are disclosed for recording and displaying grazing-incidence (i.e., steep reference beam angle) holograms supported on a substrate having thin edge-illuminatable geometry. The system and process use thin edge-illuminated substrates that facilitate optimal coupling of the reference light beam at steep angles approaching grazing incidence, while maximizing the contrast of the slanted fringe structures thereof. Different recording techniques are employed when the index of refraction of the substrate is greater than that of the recording medium, than when the index of refraction of the substrate is less than that of the recording medium. A recording and playback system of complementary design is provided for recording slanted-fringe volume holograms under relaxed conditions, without compromising the light diffraction efficiency of the holograms under different playback conditions.

Abstract: A method for reconstructing an image of a scanned object comprises the steps of collecting object data by scanning the object with a laser beam and detecting the light passing through the object; collecting perimeter data of the object during the scanning step; transforming the object data to parallel ray geometry; correcting the projection data using the perimeter data; and backprojecting the data in image space.

Abstract: An autostereoscopic display system and a method of displaying a scene in a stereoscopic form on a screen of the system include two or more reconfigurable holographic optical element (HOE) stacks in the screen. The reconfigurable HOEs may be configured to perform simple optical functions that are commonly associated with traditional optical devices, such as lenses, prisms and mirrors. However, the reconfigurable HOEs may also be configured to perform sophisticated optical manipulations, such as optimally diffusing light with respect to light intensity toward a predefined viewing region. Each reconfigurable HOE includes a hologram that is sandwiched between two electrode layers. The hologram is a holographic photopolymeric film that has been combined with liquid crystal. The hologram has an optical property that changes in response to an applied electrical field.

Abstract: A screen hologram image is reproduced on or near a plane of a hologram plate. A dynamic image is displayed at a position crossing an optical path of light beam for illumination to view a dynamic image on the screen hologram image. By using a plurality of apparatuses having the above-mentioned structure, planes of hologram plates are put without overlapping or with partial or overall lapping so that planes of master hologram images are arranged at different or the same positions in space. Thus, a dynamic image is displayed for right and left eyes for stereovision. Color display is possible. Further, an image is displayed in correspondence to a change in visual point in vertical direction or in depth direction. Thus, in an image display apparatus, a dynamic image is viewed for each of the eyes by using a hologram.

Abstract: A diffractive display system and a method of collecting first order light beams from a diffractive display of the system utilize holographic optical elements (HOEs) to deflect one of two first order diffracted light beams that emerge from each diffracting pixel of the diffractive display, so that the first order diffracted light beams can be separated from the zeroth order light beams. The utilization of the HOEs allows the system to be implemented in a compact optical configuration, without sacrificing any portion of the first order diffracted light. In a first embodiment, the system includes three HOEs that have static diffracting properties that are optimized for red, green and blue lights. For each set of light beams from a diffracting pixel of the diffractive display, the HOEs are holographically configured to deflect only one of the two first order diffracted light beams, such that the deflected first order light beam propagates in the same direction as the other non-deflected first order light beam.

Abstract: Object rays and reference rays are projected to record interference fringes on a volume hologram comprising a material exhibiting a photoinducing refractive effect, and a reconstructed image is obtained by illuminating the volume hologram with reconstruction rays. When the wavelength .lambda..sub.1 of the object rays is longer than the wavelength .lambda..sub.2 of the reconstruction rays, the reconstruction is conducted by illuminating the volume hologram with a convergent spherical wave and when the wavelength .lambda..sub.1 of the object rays is shorter than the wavelength .lambda..sub.2 of the reconstruction rays, the reconstruction is conducted by illuminating the volume hologram with a diffused spherical wave.

Abstract: A holographic display system provides a holographic image suitable for use as a nightlight in a dimly lit environment wherein the only light in the field of view of the user is essentially the light diffracted into the holographic image being replayed. The holographic display system includes a low watt light source, a hologram recorded with a reference beam matching the beam of the light source employed to replay the hologram, and an enclosing structure for holding the lightsource and hologram in registration wherein the enclosure is configured so that the only light emitted from the display system is emitted from the hologram.

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 method and a compact apparatus to read shift-multiplexed holograms on a storage medium without the need for any lenses, and without the need for moving the storage medium. The shift-multiplexed holograms have centers at different locations. The apparatus can generate an array of diverging spherical waves of reference beams, each for illuminating one of the holograms. Each hologram is read as an image on a detector array by illuminating that hologram with a corresponding diverging spherical wave of reference beam. Different holograms can be read by illuminating the medium with a different diverging spherical reference beam. The diverging beams can be from an array of sources, or can be from switching one source.

Abstract: A method for coded-wavelength multiplexing according to which a signal waves S.sub.i (r) is recorded in a holographic medium in a counter-propagating geometry using corresponding writing reference waves R.sub.i (r). The method involves selecting discrete wavelengths .lambda. and encoding reference wave vectors .rho..sub.l which make up writing reference waves R.sub.i (r) such that the writing reference waves R.sub.i (r) at each wavelength .lambda. are orthogonal. The stored signal waves S.sub.i (r) are reconstructed in the form of reconstruction waves A.sub.c (.sigma.) with reconstruction reference waves R.sub.c (r) selected from among the writing reference waves R.sub.i (r). In the event of angular multiplexing of the reference wave vectors .rho..sub.l, it is possible to use one reference wave to produce a number of reconstruction waves A.sub.c (.sigma.) and generate a mosaic of desired holographic pages.

Abstract: A method is provided for the manufacture of a holographic eye-covering article, the eye-covering article having an interference pattern corresponding to a predetermined three-dimensional object holographically prerecorded in a planar hologram layer, the interference pattern capable of being "played back" to an observer without being "played back" to said bearer. Functionality of the eye-covering article is effected in part by a light transmissive eyepiece, the eyepiece being uniaxially-curved and preferably comprising in sequence a thin web, a planar layer comprising the holographically prerecorded interference pattern, an adhesive layer, and a rigid optical substrate.

Abstract: An image reproducing method and apparatus whereby an image with a wide angle of visibility can be reproduced from a holographic stereogram in a manner less susceptible to blurring. For reproducing an image from a holographic stereogram 80 of an edge lit system, a holographic stereogram 80 is arranged on a lateral side of a cylindrically-shaped light-introducing block 81 and a reproducing illuminating light beam 82 is illuminated on the holographic stereogram 80 via the light-introducing block 81. A reproduced image 85 is produced by a diffracted light beam obtained on diffraction of the reproducing illuminating light beam 82 transmitted through the holographic stereogram 80.

Abstract: The present invention provides a method for producing double-card anti-counterfeit marks with interlock protection based on the technique which combines nuclear technology with computer-generated hologram (CGH) technology and inspecting apparatus for the mark. The invention relates to the technical field of optical information processing in physics. The technical feature of the invention is to insert potential images R,T and matched potential images R',T' in the anti-counterfeit identification marks and in the inspecting identification marks respectively by means of charged particle track image in sampling coincidence with CGH. When R coincides with R', a certain message of genuineness for an identification mark will be shown, and when T coincides with T', different specific information in thousands of ways appears to prove the genuineness of the protected objects.

Abstract: The present invention uses a hologram superimposed on a traditional picture such as a photograph or printed picture. The hologram is more viewable at certain angle ranges than at others. This allows the hologram image, the picture or a combination of both to be seen at different angles, thus allowing different visual effects. In a preferred embodiment a pre-made multi-channel hologram is superimposed over a user's portrait photograph taken in a photo booth. The multi-channel hologram is aligned with the photograph so that by varying the viewing angle of the combined picture and hologram an interesting, entertaining or educational effect, such as transforming, or "morphing," the user's face into another face or image, is seen. For example, a portrait photograph of the user can morph into an animal's face, a skeleton, a scary beast, etc. The morphing, or transformation, effect is easily achieved by insuring that the hologram image is substantially aligned with the portrait photograph.

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: A composite hologram comprises a plurality of hologram tiles arranged for display, each of said hologram tiles formed by exposing each of a plurality of different unexposed photographic plates simultaneously to light scattered by an intermediate hologram using a conjugate complex of a first reference wave from a coherent light source and to a second reference wave from said coherent light source.

Abstract: A three-dimensional image display device capable of displaying a wide screen three-dimensional image which one can easily observe from any position and direction in the same way as viewing an existing object and which device can select display conditions not to allow a three-dimensional image to be semi-transparent, and a method for making said device. Three-dimensional image data includes image data and data on relative positions of each image point (pixel). A screen panel is composed of a plurality of elementary holograms for producing diffracted light for forming each point-image on a three-dimensional image (said elementary hologram is prepared by the method according to the present invention). On the basis of the three-dimensional image data, a control computer controls a modulator and X-Y deflector so that elementary holograms on the screen panel is illuminated one by one with modulated light by raster scanning of a laser light to represent a three-dimensional image composed of point-images.

Abstract: A method for improving the resolution and contrast of images associated with coherent recording is presented, which includes conventional reconstruction with a reference wave followed by re-imaging the intermediately formed image through a system based on techniques from confocal microscopy. This method provides the opportunity to bring the benefits of the optical confocal microscope, namely resolution, contrast improvement, and the accompanying three-dimensional visualization, to such diverse imaging regimes as infrared, X-ray, ultraviolet, as well as other wave propagation systems such as seismic, sonar and ultrasound imaging. In addition, through snap-shot acquisition of said coherent recordings, the capability of time resolution may be added, thus adding functionality in wavelength regions where the confocal microscope currently operates.

Abstract: In a hologram recording and reproducing apparatus including a hologram record element having a record unit formed by a photorefractive single crystal and a pair of electrodes provided on the record unit for applying a voltage to said record unit, and an optical system for impinging light onto an incident surface of the record unit, the record unit is made of a (100) wafer of Bi.sub.12 SiO.sub.20 or Bi.sub.12 GeO.sub.20 optical single crystal belonging to a cubic system, the light is made incident upon the (100) incident surface such that an optical axis of the incident light is inclined with respect to <100> axis of the optical single crystal by an angle .theta. of 30.degree.-60.degree.. The hologram record unit is immersed in an optically transparent and electrically insulating medium having a refractive index which differs from a refractive index of the optical single crystal by not larger than 0.

Abstract: A spectacle lens structure includes a light transmitting base plate having a serrated surface defining a hologram. A thin reflective coating having a planar outer surface is provided on the serrated surface to partially reflect an incident light and allow the remaining portion of the incident light to penetrate and diffract about the serration for the formation of the holographic image. The reflective coating may be of a refractive index quite different from that of the base plate so as to provide a brazed 3-D image. If the reflective coating is made of a material having a refractive index close to the base plate, then a further coating having a high refractive index, such as ZnS, has to be provided on the reflective coating to provide a brazed 3-D image.

Abstract: Systems and methods for steering an optical path to gain access to data locations in a holographic memory cell (HMC). One of the systems includes: (1) a refractive element that receives a complex, spatially-modulated incident beam of light, (2) first and second reflective elements locatable to receive and reflect the incident beam in a Fresnel region thereof and (3) a reflective element steering mechanism, coupled to the first and second reflective elements, that moves the first and second reflective elements in tandem to steer the incident beam with respect to the HMC thereby to cause the incident beam to illuminate a location on the HMC that is a function of a movement of the first and second reflective elements.