Abstract: A method of fabricating a hologram screen having a large visual range and a hologram imaging apparatus used for the particular method of fabricating the hologram screen are disclosed. A plurality of mirrors (3) extended toward a plurality of photosensitive members (5) are arranged at a plurality of end portions (21), respectively, of a light diffuser (2). At least a reference beam (41) and object beams (42) passed through the light diffuser (2) are radiated on a plurality of the photosensitive members (5) individually thereby to form a plurality of holograms. These holograms are integrated with each other by being arranged two-dimensionally thereby to fabricate a hologram screen. Among the mirrors (3), a reference beam-side mirror (31) arranged nearer to the light source of the reference beams (41) is extended from the light diffuser (2) by a length varied with the position of the photosensitive member (5) to be exposed.

Abstract: A rain sensor for a motor vehicle, having a transmitter emitting radiation, a receiver, and a holographically embodied diffractive element that has a linear-grating-like structure.

Abstract: An image display device comprising a holographic screen and an image projection device for projecting an image beam onto the holographic screen at an upward or downward angle is provided, wherein a forward view color difference &Dgr;u′v′ between a chromaticity value (u′, v′) at the center of the holographic screen when a white image is projected onto the holographic screen by the image projection device and a standard chromaticity value (u′o, v′o) is 0.04 or less when the projection angle of the image beam onto the center of the holographic screen is set to any angle within a specified projection angle range of 20 to 45°, whereby a image display device and holographic screen can be provided wherein the range of the projection angle of the image beam, in which an image with excellent color reproducibility can be displayed, is wide.

Abstract: Quality of a reproduced light beam is improved, and rewriting and recording are performed at high speed without erasing data. Each page of a hologram is newly recorded so that the maximum point of diffraction light beam intensity in reproducing the newly recorded hologram is located at a position where diffraction light beam intensity from a data page of a hologram which has been previously recorded in a hologram recording medium is minimized at the time of reproducing the data.

Abstract: According to one aspect a method for manufacturing a holographic storage medium includes providing one or more data masks with data to be recorded, illuminating the one or more data masks onto the medium with a plane wave object beam from a laser light source operating at a record wavelength, propagating a reference beam at an incident angle to the medium to record the one or more data masks on the medium, and altering the incident angle of the reference beam for each of the one or more data masks, wherein each of the one or more data masks recorded on said medium can be read bit by bit using a laser light source operating in a readout range of wavelengths different from the record wavelength.

Abstract: A security device includes a holographic optically variable effect generating structure having at least two discrete section. The sections that generate in response to white light illumination an optically variable image having at least two defined graphical elements located at or near an image plane either on or adjacent to the plane of the device. In response to coherent illumination, the sections generate at least two discrete covert images, in the form of indicia, whose image planes are located at a distance away from the real place of the device. The covert images are reconstructed at different angles to a normal to a substrate supporting the device such that the covert images are spatially separated on their image plane, the covert images being non-visible under white light illumnination.

Abstract: A planar substrate having a first diffractive element for coupling light waves of different colors into the substrate and guiding the light waves by successive internal reflections. A second diffractive element, disposed on the substrate, causes the guided light waves to be partially transmitted out of the substrate where the light waves encounter the second diffractive element. Because light waves of each color are reflected at different reflection angles, the light waves with smaller reflection angles encounter the second diffractive element at more locations than those with larger reflection angles, resulting in color non-uniformity in the light transmitted out from the substrate surface. One or more interfaces are provided between the surfaces of the substrate to selectively reflect the light waves having larger reflection angles toward the second diffraction element, so that light waves of different colors encounter the second diffraction element substantially at the same number of locations.

Abstract: An optical storage medium of the present invention enables storage of data with high precision at high speed, and rewriting of data at high speed without an erasing process. Optical storage, reading and retrieving methods and optical storage, reading, and retrieving apparatuses using the medium are also provided. The optical storage medium has at least a polarization-sensitive member having the photo-induced birefringence property, such as a member made of polyester polymer having cyanoazobenzene as a side chain. The above apparatuses have spatial light modulator capable of modulating polarization. The modulator provides information of bit of two-dimensional data to each corresponding pixel by application or non-application of a voltage, and modulates the polarization of the beam incident on each pixel. Thereby, a signal beam transmitted through the spatial light modulator having a spatial polarization modulation corresponding to the two-dimensional data is obtained.

Abstract: Optical infinite impulse response (IIR) filters are efficient polarization mode dispersion (PMD) compensators, requiring fewer stages than finite impulse response (FIR) filters. IIR filter architectures incorporating allpass filters allow the phase and magnitude compensation to be addressed separately. An IIR filter PMD compensator comprising a polarization beam splitter, allpass filters, polarization rotation devices, a 2×2 filter, and a polarization beam combiner optically coupled is described.

Abstract: A method of recording holograms includes: generating a first signal-beam from a signal-beam source and a first reference beam from a reference-beam source; recording a first hologram in a holographic medium from an interference between the first signal beam and the first reference beam; shifting the reference-beam source after the act of recording the first hologram; generating a second signal beam from the signal-beam source and a second reference beam from the reference-beam source after the act of shifting the reference-beam source following the recording of the first hologram; and recording a second hologram in the holographic medium from an interference between the second signal beam and the second reference beam.

Abstract: An imaging system for motor vehicles has a holographic screen, which scatters incident narrow band light at a predetermined solid angle, and a modulator and a lens to project images on the holographic screen. A holographic, transparent ray uniter, which allows broad band ambient light to pass through essentially unimpeded, guides the narrow band light, coming from the holographic screen to the viewer, whereby a virtual image is produced at the viewing location by means of an imaging function. Images from the outside of the motor vehicle are shot by means of a camera system and are faded as virtual images into the windshield of the motor vehicle in order to enable there additionally a view to the rear or to the side.

Abstract: The invention is concerned with a volume hologram medium obtained by multiple recording of holograms, which is improved in terms of just only security for forgery prevention but also aesthetics. A volume hologram medium 29′ comprises a reflection hologram in which a stereoscopic image of a three-dimensional object and an image of a plane pattern of a mask plate are recorded by interference of the same reference light beams having the same angle of incidence and the same wavelength with object light beams having mutually different angles of incidence. The stereoscopic image of the three-dimensional object is reconstructed in the form of diffracted light 31 in a single color and in angle relations close to recording conditions, and the image of a plane pattern of the mask plate is reconstructed as diffracted light 32b, 32′b at various angles of incidence of white illumination light 30 and in different colors depending on those angles of incidence.

Abstract: An information carrier includes information in the form of a hologram. In order to increase protection against copying and/or as a simple recognizable additional security feature of this information carrier, the hologram is the combination of a transmission hologram and a reflection hologram.

Abstract: A privacy filter for use on an electronic display screen, such as a PDA display screen or a laptop display screen, is constructed using holographic imaging technology. The privacy filter consists of a flexible, optically clear photopolymer film having a plurality of holographic images formed thereon. The key aspect of the present disclosure is constructing the master holographic images by imaging the master holographic recording plates at a severe side angle “off angle”. By shooting the hologram at this “off angle”, the resulting hologram is not visible to a person looking directly (perpendicularly) at the resulting hologram. However, the holograms are visible within the remaining fields of view to the right and to the left of center. Creation of the holograms in this manner creates an effective blocking tool for use in the context of a privacy filter.

Abstract: A hologram recording film has a hologram image of an object recorded in a volume hologram photosensitive material by holographic duplication and further has a hologram image of an additional information pattern, e.g. a character or an image, recorded superimposedly in the same volume hologram photosensitive material simultaneously with the holographic duplication so that the additional information pattern is reconstructable in a plane with a depth from the hologram plane. Reflection type additional information is recorded in the hologram recording film so as to be reconstructable simultaneously in superimposition with a reconstructed image from the volume hologram. In addition, transmission type additional information that is in mirror image relation to the reflection type additional information is recorded in the hologram recording film so as to be reconstructable simultaneously in superimposition with the reconstructed image from the volume hologram.

Abstract: A method and system of recording successive holograms in a recording medium including a reflective substrate layer, a polarization shifting layer, and a photorecording medium layer is presented. A reference beam and an object beam are propagated at a first direction to a first area of the photorecording medium layer, where the reference beam and object beam have a same first polarization and interfere to produce a first interference grating. The reference beam and object beam are reflected with the reflective substrate layer to be incident the photorecording medium at a second direction, where the reference beam polarization and object beam polarization are altered with the polarization shifting layer to have a same second polarization. The reflected reference beam and object beam interfere to produce second interference grating, with the first polarization and second polarization being different.

Abstract: A holographic optical element comprising at least two sets of regions, the regions of each set being different from the regions of the other set(s) and being interleaved or overlapping with the regions of the other set(s) and being constructed such that light incident on each set of regions is directed to a respective one of a plurality of viewing zones. The holographic optical element is typically incorporated in a display device such as a stereoscopic display device.

Abstract: A substrate surface 10 having a photo-sensitive material surface thereon is simultaneously exposed to four plane waves of light at angles of incidence &thgr;, −&thgr;, &phgr; and −&phgr; subtending from the normal of the surface. The four plane waves create an interference pattern on the substrate so as to cause the formation of a periodic structure on the photo-sensitive material surface of the substrate.

Abstract: A method for the generation of volume spatially-resolved holographic data storage within a photosensitive glass sample that incurs changes of optical properties in response to two-photon absorption, the method including directing non-ultraviolet pulsed laser radiation at the photosensitive glass sample to induce changes of optical properties in the glass sample, splitting of the pulsed laser radiation, prior to reaching the glass sample, into an object beam having a direct optical path of a first predetermined length and a reference beam, changing the path of the reference beam to have an indirect optical path of a second pre-determined length, focusing each of the object beam and the reference beam along the respective optical paths, to intersect at a focal volume of the glass sample, and therein to cause the two-photon absorption, providing a variable time delay in the direct path of the object beam so that it reaches the chosen region within the focal volume of glass at the same time as the reference beam,

Abstract: Holography in which an array of overlapping holograms is recorded or reconstructed in a recording medium, holograms being produced by interference of a reference beam and a signal beam, in which the reference beam is a phase beam which consists essentially of a multitude of rays of varying angle of incidence and non-uniform phase, in which the process comprises changing the orientation of the phase beam for recording or reconstructing different holograms, wherein phase beam orientation is changed relative to the medium while maintaining the medium stationary in order to enable recording or reconstruction of individual holograms at a given location of the medium.

Abstract: A holographic display element for three-dimensionally displaying a three-dimensional model and a plane image, for example, in a superimposed manner, which is prevented from causing a change in color or a reduction in contrast of the foreground pattern at an overlap between the foreground pattern and the background pattern. The holographic display element is formed from a single reflection type volume hologram layer, wherein a foreground pattern and a background pattern are recorded so that the two patterns can be reconstructed away from each other in space and a portion of the background pattern that is shadowed by the foreground pattern as superimposed thereover is vacant.

Abstract: A reflection type color display device and a reflection type of direct-view color display device are provided. The reflection type color display device includes a spatial light modulator having a collection of pixels and a controllable transmittance per pixel, with a reflection type hologram color filter located on the back side of the modulator. The reflection type of direct-view color display device includes a hologram color filter which has an array of light-collecting holograms. Each of the light-collecting holograms has its own hologram color filter, reflection type hologram, and transmission type spatial light modulator located between the hologram color filter and the reflection type hologram.

Abstract: Disclosed is an apparatus and method of illuminating an image display via an electrically switchable holographic optical element. The method includes a first electrically switchable holographic optical element (ESHOE) receiving illumination light. The first ESHOE comprises oppositely facing front and back surfaces. The first ESHOE focuses a first component (e.g., p-polarized blue light) of the illumination light while transmitting the remaining components of the illumination light without substantial alteration. An image display is provided and receives the focused first component. In response to receiving the focused first component, the image display emits image light. The first ESHOE receives and transmits this image light without substantial alteration. In one embodiment, the focused first component emerges from the first ESHOE at the back surface thereof, and the first ESHOE receives the image light at the back surface.

Abstract: A method is provided for producing a holographic optical element that is comprised of at least one primary hologram (as defined herein) and at least one complementary hologram (as defined herein). The holographic optical element is useful as a security device, since it is relatively easily produced and yet is uncopyable in total. Also disclosed are methods for establishing the authenticity of the holographic optical element.

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: An image display device comprising a holographic screen and an image projection device for projecting an image beam onto the holographic screen at an upward or downward angle is provided, wherein a forward view color difference &Dgr;u′v′ between a chromaticity value (u′, v′) at the center of the holographic screen when a white image is projected onto the holographic screen by the image projection device and a standard chromaticity value (u′o, v′o) is 0.04 or less when the projection angle of the image beam onto the center of the holographic screen is set to any angle within a specified projection angle range of 20 to 45°, whereby a image display device and holographic screen can be provided wherein the range of the projection angle of the image beam, in which an image with excellent color reproducibility can be displayed, is wide.

Abstract: The invention relates to a skip-sorted spatial multiplexing holographic storage technique that addresses the problems of cross-talk, image distortions, and physical change of the medium encountered in current recording processes in which photopolymer media are used. The skip-sorted technique involves storing holograms in layers of arrays, such that a substantially uniform background exposure is provided for subsequent layers.

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 single photographic subsystem 2 photographs an original image for a hologram and provides an image information file Fp. In addition, this subsystem provides a management information file Fm for storing management information about the image information file Fp. An image processing section 4 generates a composite image file Fs by applying specified image processing to the image information file Fp and the management information about the management information file Fm provided from the single photographic subsystem 2 via a transmission system 3a. A hologram printer 5 receives the composite image file Fs generated in the image processing section 4 and prints a holographic stereogram based on this composite image file Fs.

Abstract: A holographic optical element comprising at least two sets of regions, the regions of each set being different from the regions of the other set(s) and being interleaved or overlapping with the regions of the other set(s) and being constructed such that light incident on each set of regions is directed to a respective one of a plurality of viewing zones. The holographic optical element is typically incorporated in a display device such as a stereoscopic display device.

Abstract: An optical crossbar switch system includes: a mask comprising multiple patterns, wherein at least one of the multiple patterns is a diffractive pattern; and a spatial light modulator positioned to receive at least one optical input beam and selectively couple at least a portion of each of the at least one input beam to one of the patterns of the mask, each coupled portion defining an intermediate beam, wherein each pattern, when selected by the spatial light modulator, is configured to redirect the intermediate beam to one of N targets, where N is an integer greater than two. Further, a method for selectively coupling at least one input beam to one of multiple output channels includes: selectively coupling at least a portion of each of the at least one input beam to one of multiple patterns on a mask; and diffracting at least one of the coupled portions from the mask to one of the output channels.

Abstract: This invention relates to the photo-sensitive thermoplastic top-layer of optical media for registration of holograms, where the media consists of three transparent layers where the bottom layer is a glass substrate, the mid layer is an electro-conductive film of tin dioxide, and the top layer is a thermoplastic photo-sensitive amorphous molecular semiconductor film made of a matrix which has donor properties and forms transport bands for holes, and were the matrix is doped with; a photo-sensitive substance (CICT) that has intramolecular physically separated parts with donor and acceptor properties, respectively, and which creates an intramolecular electron-hole pair when absorbing a light quantum, and which has a HOMO-level which is below the HOMO-level of the matrix substance, and a substance with acceptor properties that forms transport bands for electrons, which has a similar ring structure as the acceptor part of CICT to ensure a barrierless transfer of excited electrons from CICT to acceptor-molecules

Abstract: A multicolored reflection liquid crystal display device includes a pair of substrates having a reflective holographic polymer dispersed liquid crystal (H-PDLC) film disposed therebetween. The H-PDLC film contains at least two different reflection gratings capable of reflecting two different wavelengths of light. A multicolored reflection H-PDLC is obtained by simultaneously illuminating a plurality of regions of a film comprised of a mixture of a liquid crystal and a photo-polymerizable monomer with a plurality of holographic light patterns capable of providing liquid crystal layers of different spacings so as to obtain different reflection gratings in each of the regions. A mask is placed between each of the laser light beams and the film to form a pattern of light and dark regions on the film. Each mask is positioned such that at least one light region of a first beam pair coincides with at least one dark region of a second beam pair within the film.

Abstract: A method and apparatus are presented for a tunable device for measuring the optical spectrum of a DWDM signal on a per channel basis. The device is an InP-semiconductor based tunable ring resonator. In a preferred embodiment the typical size of the chip is approximately 250&mgr;m×250&mgr;m. The three main sections of the device comprise a straight input passive waveguide, a straight output absorbing waveguide, and a tunable ring resonator. The ring resonator sets up a wavelength selective resonant cavity, allowing measurement of OP and OSNR across the free spectral range of the device, centered at a nominal service wavelength. In the preferred embodiment, the device can measure the OP and OSNR of an arbitrary demultiplexed DWDM signal, with a measurement time of approximately 225 microseconds. Inasmuch as the device is simply measuring optical performance parameters within a particular frequency (i.e.

Abstract: A color hologram recording medium 2 includes volume hologram recording mediums 14R, 14G and 14B for diffracting light of wavelengths different from each other. Reconstruction patterns 1R, 1G and 1B of the volume hologram recording mediums 14R, 14G and 14B are recorded so that the reconstruction patterns 1R, 1G and 1B are reconstructed at reconstruction positions different from each other. Thus, the color hologram recording medium 2 can have a wide variety of designs and artistic characters that the recorded color reconstruction patterns vary depending on watched directions.

Abstract: A wavelength division multiplexing device and method includes two prisms having a pair of coated, highly reflective opposed faces forming an etalon. A volume phase grating is sandwiched between the two prisms. The volume phase grating is positioned between the highly reflective opposed face portions so that a light beam incident on the etalon undergoes a preselected number of multiple reflections between the highly reflective face portions and a preselected number of traversals through the volume diffraction grating, whereby wavelengths satisfying a Bragg condition on each traversal are diffracted out of the volume grating means. One prism may be designed to separate TE and TM polarized light, and the other prism may be designed to combine the TE and TM modes so that the result is polarization independent. Each prism includes at least one transparent output face through which the separately diffracted wavelengths are transmitted at respective angles.

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 and device provide efficient wavelength division multiplexing/demultiplexing (WDM) including reduced signal distortion, higher wavelength selectivity, increased light efficiency, reduced cross-talk, and easier integration with other planar devices, and lower cost manufacturing. The method and device include a planar holographic multiplexer/demultiplexer having a planar waveguide, the planar waveguide including a holographic element that separates and combines pre-determined (pre-selected) light wavelengths. The holographic element includes a plurality of holograms that reflect predetermined light wavelengths from an incoming optical beam to a plurality of different focal points, each pre-determined wavelength representing the center wavelength of a distinct channel. Advantageously, a plurality of superposed holograms may be formed by a plurality of structures, each hologram reflecting a distinct center wavelength to represent a distinct channel to provide discrete disperstion.

Abstract: Disclosed is an illumination system using optical feedback to maintain a predetermined illumination output. The illumination system employs an electrically controllable optical filter for filtering light incident thereon. The illumination system also includes a light detector for detecting at least a portion of the light filtered by the electrically controllable optical filter. The light detector is in data communication with the electrically controllable optical filter. Some or all light filtered by the electrically controllable optical filter is detected by the light detector, which, in turn generates a corresponding signal that is compared to at least one predetermined value. If the signal generated by the light detector differs when compared to the at least one predetermined value, one or more filtering characteristics of electrically controllable optical filter are varied which, in turn, varies the amount of light filtered by the electrically controllable optical filter.

Abstract: A master hologram is generated in a first optical medium by use of a plurality m of different reference beams, each beam bearing information suitably recorded in one or more of a plurality n layers of the second optical medium that are distinct from layers in which information in all other beams is suitably recorded. The generated master hologram is then used to optically holographically stamp, or record, multi-layer bit-oriented optical media by writing all n layers of the volume of the blank optical medium with m recording beams produced by simultaneously illuminating the master hologram with all m different reference beams, each illuminating reference beam being at a different reference angle and from a coherent light source which is incoherent with respect to every other illuminating reference beam.

Abstract: A thickness of each hologram lens for forming a hologram color filter is set so as to be smaller as the wavelength of light to be diffracted by each hologram lens is shorter. A thin plate glass layer is bonded to a surface of the hologram color filter such that it is in a firm contact therewith by adhesive agent and a sum of the thickness of the thin plate glass layer and thickness of the adhesive agent is smaller than the shortest focal length of the focal lengths in glass of a plurality of the hologram lenses. As a result, light diffracted and divided by the hologram color filter is focused on a picture element electrode of a corresponding color properly thereby eliminating deterioration of color reproduction due to mixing of colors. Further, upon production of the hologram color filter from hologram recording material, an influence of a fringe rotation is compensated.

Abstract: Described herein is an apparatus for producing three-dimensional staic or moving images. In one embodiment, the apparatus includes an image generator and an optical device. The image generator generates a plurality of image elements including first and second image elements. In one embodiment the image elements constitute coherent beams of light encoded with image information, wherein the coherent beams of light are sequentially generated by one or more laser scanners of the image generator. The optical device receives the plurality of image elements on a first planar surface thereof and, in response, produces first output light rays and second output rays corresponding to the first and second image elements, respectively. The first and second output light rays, when seen by an observer, appear to originate from first and second common points, respectively. The first and second common points are spaced from each other and from the first planar surface.

Abstract: This invention pertains to the design of optimized far field viewing devices that simultaneously produce bright far field holographic light patterns and achieve good see-through performance to present a well focused scene. A far field transmission hologram recorded on a transparent substrate has regions having high diffraction efficiency juxtaposed with regions having low diffraction efficiency. The high diffraction efficiency regions contribute to production of bright far field holographic light patterns, whereas the low diffraction efficiency regions contribute to see-through performance.

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: The present invention provides a hologram color filter having a drastically decreased dependence of diffraction efficiency on wavelength and well corrected for a color balance among the three colors R, G and B comprising an array of converging element holograms 5′, each of which enables white light incident at a given angle &thgr; with respect to a normal line of a hologram recorded surface thereof to be spectroscopically separated by wavelength dispersion in a direction substantially along the hologram recorded surface, wherein the converging element holograms 5′ have each a plurality of hologram pieces 51 and 52 superposed on each other or multi-recorded therein, which, with respect to the white light 3 incident at the given angle &thgr;, have substantially identical spatial wavelength distributions of wavelength dispersion and different peak wavelengths of diffraction efficiency.

Abstract: A paper support has an adhesive layer and a metallized holographic image, wherein the metallized holographic image includes at least two holograms, such that the first hologram is visible only by non-coherent light and the second hologram is visible only by coherent light. The holographic images are formed on a photosensitive element on a polymeric support by imaging steps, which include metallizing the holographic images and overcoating the holographic images with an adhesive layer. Next, the metallized holographic images are transferred to the paper by laminating the adhesive layer to the paper at a predetermined temperature and pressure, and subsequently delaminating the polymeric support from the paper, such that the holographic image remains on the polymer support for reuse.

Abstract: A full-color hologram capable of generating a bright image and reproducing colors in all color regions is formed by multiple recording or multilayer recording with four different dominant wavelengths for reconstruction. The full-color hologram has one reconstruction wavelength in the vicinity of the peak wavelength 555 nm of the spectral luminous efficiency curve, i.e. in the range of 550 nm to 560 nm, and further has three other reconstruction wavelengths in the three primary color regions of red, blue and green, i.e. in the three regions of 615 nm to 680 nm, 380 nm to 470 nm, and 485 nm to 515 nm, respectively.

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: The invention involves a holographic system containing a photopolymer-type storage medium located in the system's optical path, where the medium is rotated around a first axis such that the surface of the medium is in a non-orthogonal relationship with the optical path, and a spatial light modulator also located in the optical path, where the modulator is rotated around a second axis that is substantially orthogonal to the first axis, and wherein the surface of the modulator is in a non-orthogonal relationship with the optical path. This arrangement compensates for at least a portion of aberration introduced by the photopolymer media, thereby allowing presentation of a flatter, more focused, and less distorted image at the sensor.

Abstract: A holographic display system comprising left and right optical systems is disclosed, The optical systems each comprise an image display operable to display an input image and first and second holographic devices. The first holographic device is operable to project the input image to overlap with the input image projected from the other of the left and right optical systems to form a resultant image with a first aspect ratio. The second holographic device is operable to project the input image to overlap with the input image projected from the other of the left and right optical systems to form a resultant image with a second aspect ratio, different from the first aspect ratio. A method of changing the aspect ratio of an image is also disclosed.