Abstract: The invention is directed to a holographic data storage system including a spatial light modulator device (SLM) that comprises optical elements in the form of polymer dispersed liquid crystal (PDLC) elements. The PDLC elements are individually controllable, and can be made substantially transparent or substantially diffusive. The “on” or “off” state of each PDLC element is defined by whether the given PDLC element is transparent or diffusive. Additional states may also be defined for the PDLC elements, e.g., based on a level of diffusiveness of the PDLC elements. Also, a mirror layer may be added adjacent the PDLC elements to define a reflective-mode SLM. In any case, the SLM is used to encode bit maps into a holographic object beam.

Abstract: Techniques for reading the spectral content of a spatial-spectral grating in an inhomogeneously broadened transition (IBT) material include directing multiple probe waveforms to probe a spatial mode of the IBT material. Each probe waveform is a linear frequency modulated chirp; each probe waveform partially overlaps in frequency with a different probe waveform; and multiple output signals are detected from the IBT material in response. Based on the multiple output signals, a readout signal is determined that represents a complete or nearly complete temporal map of the spectral content of the spatial-spectral grating. Calibration of the frequency content can be achieved by simultaneously reading out calibration spectral features. These techniques allow high-bandwidth spectral content to be read with segmented narrow bandwidth chirp probe waveforms and low-bandwidth high-dynamic-range detectors and digitizers.

Abstract: This invention provides a hologram recording apparatus for recording an interference fringe, generated by interference of a first light beam subjected to spatial light modulation by recording data with a second light beam, in a recording area of a hologram recording medium, the hologram recording apparatus including: a random phase body for randomizing the wave front of the second light beam, and a multiplex recording control unit for recording the interference fringe of the first light beam and the second light beam in the same recording area of the hologram recording medium each time the random phase body is rotated.

Abstract: A display device includes a spatial light modulator and a light generator. The spatial light modulator may have an array of modulating elements with a plurality of image regions. The light generator may be configured to direct a different one of a plurality of substantially stationary light bands onto each of a plurality of the image regions of the array of modulating elements.

Abstract: An optical recording/reproducing apparatus having excellent resistance against vibration and noise. In recording, coherent light is polarization-modulated with a spatial light modulator to generate signal light and reference light whose polarization directions are crossed at right angles. The signal light permeates a polarizing beam splitter, and is incident to a quarter wavelength plate. The reference light passes through a passing hole, is diffused by a light diffuser and is incident to the quarter wavelength plate. The reference and signal light are converted into circularly polarized light which revolve in directions opposite to each other and condensed by a condenser lens, and then a predetermined area of an optical recording medium is irradiated with the reference and signal light. Thus, the reference and signal light are generated by modulating the incident light from the same light source and are coaxially incident to the polarizing beam splitter.

Abstract: A holographic recording method and a holographic recording apparatus capable of selectively rewriting or erasing only desired data without degrading data other than the desired data are provided. Holograms are multiple recorded per file, and page data in one file is multiple recorded, while page data in one file and page data in another file are not multiple recorded. Therefore, only the desired file can be selectively rewritten or erased without degrading the other files.

Abstract: To operate an optical device comprising an SLM with a two-dimensional array of controllable phase-modulating elements groups of individual phase-modulating elements are delineated, and control data selected from a store for each delineated group of phase-modulating elements. The selected control data are used to generate holograms at each group and one or both of the delineation of the groups and the selection of control data is/are varied. In this way upon illumination of the groups by light beams, light beams emergent from the groups are controllable independently of each other.

Abstract: An optical information recording/reproducing apparatus generates information light by modulating light emitted by a light source device with a light modulator depending on the information to be recorded and generates reference light for recording by modulating the light emitted by a light source device with a light modulator. The information light and the reference light for recording are projected upon an optical information recording medium such that they converge in different positions, and information is recorded in a hologram layer in the form of an interference pattern between the information light and the reference light for recording.

Abstract: The present invention provides improved Wavefront Coding imaging apparatus and methods composed of optics, a detector, and processing of the detected image. The optics are constructed and arranged to have the characteristic that the transverse ray intercept curves form substantially straight, sloped lines. The wavefront coding corrects for known or unknown amounts of “misfocus-like” aberrations by altering the optical transfer function of the imaging apparatus in such a way that the altered optical transfer function is substantially insensitive to aberrations. Post processing then removes the effect of the coding, except for the invariance with regard to aberrations, thereby producing clear images.

Abstract: The invention is directed to holographic recording techniques that generate a data encoded object beam and a reference beam using a spatial light modulator of the holographic recording system. An input light source, e.g., comprising laser light conditioned by optical elements, can be used to illuminate the spatial light modulator. Different portions of the spatial light modulator are used to create the data encoded object beam and the reference beam, which are then made to interfere in a holographic medium to record a hologram.

Abstract: The invention is directed to holographic recording techniques that generate a data encoded object beam and a reference beam using a spatial light modulator of the holographic recording system. An input light source, e.g., comprising laser light conditioned by optical elements, can be used to illuminate the spatial light modulator. Different portions of the spatial light modulator are used to create the data encoded object beam and the reference beam, which are then made to interfere in a holographic medium to record a hologram.

Abstract: Optical information is stored in an optical information recording medium having an information recording layer utilizing holography with an optical information recording apparatus which includes security features. An input device is used to input individual information which is unique to an individual. An information light carries information to be recorded on the optical information recording medium. A phase modulation pattern is generated based on the individual information. A recording reference light is generated including a phase modulator for spatially modulating a phase of the reference light, for generating reference light for recording having a phase spatially modulated based on the phase modulation pattern information. A recording optical system illuminates the information recording layer on the same side with both the information light and the reference light.

Abstract: The present invention makes it possible to reduce the size of an optical system for multiplex recording or reproduction of information utilizing holography. A pick-up of an optical information recording/reproducing apparatus generates information light by spatially modulating laser light emitted by a laser source device with a spatial light modulator depending on the information to be recorded and generates reference light for recording having a spatially modulated phase by spatially modulating the phase of laser beam emitted by the light source device with a phase-spatial light modulator. The information light and the reference light for recording are projected upon an optical information recording medium such that they converge in different positions, and information is recorded in the hologram layer in the form of an interference pattern as a result of interference between the information light reflected by a reflecting film and the reference light for recording.

Abstract: An angular multiplexing apparatus for a holographic storage medium. The angular multiplexing apparatus includes a reconstructing reference beam generator, translated in parallel to a number of positions, for generating a number of reconstructing reference beams which propagate in parallel to one another at the positions, respectively, and a mirror array having a plurality of planes of reflection for generating a plurality of reflected beams which are converged into a reconstructing position of the holographic storage medium.

Abstract: An optical recording/reproducing apparatus having excellent resistance against vibration and noise is provided. In recording, coherent light is polarization-modulated with a spatial light modulator to generate signal light and reference light whose polarization directions are crossed at right angles with each other. The signal light permeates a polarizing beam splitter, and is incident to a quarter wavelength plate. The reference light passes through a passing hole, is diffused by a light diffuser and is incident to the quarter wavelength plate. The reference and signal light are converted into circularly polarized light which revolve in directions opposite to each other and condensed by a condenser lens, and then a predetermined area of an optical recording medium is irradiated with the reference and signal light. Thus, the reference and signal light are generated by modulating the incident light from the same light source and are coaxially incident to the polarizing beam splitter.

Abstract: An Interferometric Modulator (IMod) is a microelectromechanical device for modulating light using interference. The colors of these devices may be determined in a spatial fashion, and their inherent color shift may be compensated for using several optical compensation mechanisms. Brightness, addressing, and driving of IMods may be accomplished in a variety of ways with appropriate packaging, and peripheral electronics which can be attached and/or fabricated using one of many techniques. The devices may be used in both embedded and directly perceived applications, the latter providing multiple viewing modes as well as a multitude of product concepts ranging in size from microscopic to architectural in scope. In another aspect, a structure for modulating light comprises modulators of light each including an interference cavity for causing interference modulation of the light.

Abstract: A screen for image display apparatus according to the present invention has a base member, a light absorption layer formed on the base member and adapted for absorbing light of a visible light range, and a light control layer formed on the light absorption layer. The light control layer reflects projected image display light to form an image and has a reflection wavelength selection function of selectively reflecting light of the wavelength range of the image display light. By using the screen for image display apparatus according to the present invention, a user can easily enjoy large-screen image display even in a bright environment.

Abstract: A holographic recording apparatus which can stably record data to be recorded onto a recording medium. The holographic recording apparatus of the present invention includes: a light source for generating a coherent reference light beam; a signal light generation unit including a spatial light modulator for spatially modulating the reference light beam in accordance with information data to generate a signal light beam; an interference unit for directing the signal light beam and the reference light beam toward a recording medium through an objective lens to form a region of a diffraction grating formed by an optical interference pattern within the recording medium; a lens positioning unit for positioning the objective lens with respect to a recording surface of the recording medium; and a light-receiving unit for detecting a returned beam that is returned from the recording medium through the objective lens.

Abstract: The present invention makes it possible to reduce the size of an optical system for multiplex recording or reproduction of information utilizing holography. A pick-up (11) of an optical information recording/reproducing apparatus generates information light by spatially modulating laser light emitted by a light source device (25) with a spatial light modulator (18) depending on the information to be recorded and generates reference light for recording having a spatially modulated phase by spatially modulating the phase of laser beam emitted by the light source device (25) with a phase-spatial light modulator (17). The information light and the reference light for recording are projected upon an optical information recording medium (1) such that they converge in different positions, and information is recorded in the hologram layer (3) in the form of an interference pattern as a result of interference between the information light reflected by a reflecting film (5) and the reference light for recording.

Abstract: A spatial light modulator (SLM) 101 has a multiplicity of pixels 101a arranged in a lattice form for selecting a transmission state (on) and a blocking state (off) of light on each pixel thereby spatially modulating light intensity. The spatial light modulator 101 has a light transmissivity distribution over whole pixels is set such that a light transmissivity is lower at and around a center and increased with increasing distance from the center.

Abstract: A holographic apparatus includes a mask for modulating a signal beam to generate a modulated signal beam; a conical prism, which has a cone portion and a base portion, for refracting a reference beam to generate a refracted reference beam, wherein the refracted reference beam interferes with the modulated signal beam in a holographic medium to thereby record data thereon, the base portion facing the holographic medium. The holographic apparatus can be miniaturized by a positional relationship between the conical prism and the holographic medium.

Abstract: The present invention is related to a method for performing digital holographic imaging (DHI), said DHI being characterized by the fact that images of a sample are obtained by applying numerical means to reconstruct holograms of the sample. In the method of the invention, the sample is in a medium with controlled properties that influence the behaviour of the sample, and/or that influence the process of hologram formation. The information content of one hologram, or of a plurality of holograms, recorded with the sample in one medium, or in a plurality of medium, is used to reconstruct one image of the sample, or a plurality of images of the sample, that describe quantitatively one property of the sample, or a plurality of properties of the sample. The present invention is also related to an apparatus with which to perform said method.

Abstract: A holographic imaging system and method includes a radiation source for generating radiation. A data base has a set of elements, each element is indicative of a trajectory of a light ray exiting a point in a recorded scene. A spatial light modulator is receptive of the radiation from the radiation source and the elements of the data base mapped to the spatial light modulator, thereby projecting from the spatial light modulator an optical signal in the nature of a two dimensional bitmap of the recorded scene. A diffractive optical element includes a set of basis fringes receptive of the projected optical signal from the spatial light modulator for diffracting the optical signal in a specified direction. A multiplexer is receptive of the elements of the data base for multiplexing the elements of the data base to the spatial light modulator. A timing device synchronizes multiplexing the elements of the data base to the spatial light modulator and diffracting the optical signal in a specified direction.

Abstract: An optical element has of a set a plurality of three-dimensional cells. A specific amplitude and a specific phase are defined in each individual cell. Each cell has a concave part formed by hollowing a part having an area corresponding to the specific amplitude by a depth corresponding to the specific phase. The individual cell has a specific optical property so that, when incident light is provided to the cell, emission light is obtained by changing an amplitude and a phase of the incident light in accordance with the specific amplitude and specific phase defined in the cell.

Abstract: A description is provided of an optical information recording and reproducing apparatus having a volume holographic memory. The apparatus is capable of recording an interference pattern in the volume holographic memory in high density and can be made small-sized.

Abstract: This invention discloses a method of producing, in a solid transparent material (3), a hologram of an object; the method includes the steps of: developing a three-dimensional mathematical model of an electro-magnetic field emanating from the object, the field producing an image of the object; computing a corresponding three-dimensional set of points, light scattered from which reconstructs the field; and focusing a pulsed laser beam into the solid transparent material onto each of the points sequentially, the beam being capable, when focused, of causing optical breakdown in the solid transparent material.

Abstract: Holographic methods for recording fast movies whose speed is limited by the laser pulse duration if the recording material has sufficient sensitivity to reliably record a frame of the fast event with a single pulse. The method we describe uses the selectivity of multiplexed holograms to resolve frames that are recorded with adjacent pulses. Specially designed pulse generators are used to generate the signal and reference pulse trains. We experimentally demonstrate the system by making movies of laser induced shock waves with a temporal resolution of 5.9 ns, limited by the pulse width of the Q-switched Nd:YAG laser used in the experiments.

Abstract: In a hologram recording method for forming a plurality of areas of a refractive index light interference pattern of a coherent signal light beam in accordance with information data within a recording medium having a shape of parallel flat plates, the signal light beam and the recording reference light beam cross each other within the recording medium, and a gate light beam having a second wavelength for revealing recording sensitivity of the recording medium is simultaneously irradiated to the recording medium so as to pass through a portion of the recording reference light beam and demarcate a volume smaller than that of this crossing portion.

Abstract: In a storing mode of an apparatus for storing and retrieving a sequence of digital page data, a first/second complex reference beam and a modulated signal beam converge on a storing location to generate a sequence of first/second interference patterns to be sequentially stored on a holographic medium. A shift selectivity of the first complex reference beam is larger than that of the second complex reference beam so that the second interference pattern is used as a servo pattern to sequentially determine where the first interference patterns have been stored.

Abstract: In a storing mode of an apparatus for sequentially storing and retrieving digital page data, a first and second complex reference beams and a modulated and second signal beams converge on a first/second location to generate a sequence of first and second interference patterns to be sequentially stored on a holographic medium. A shift selectivity of the first complex reference beam is larger than that of the second complex reference beam so that the second interference pattern is used as a servo pattern to sequentially determine where the first interference patterns have been stored.

Abstract: Apparatus and methods are disclosed for spatially routing an optical pulse (data pulse) of an electromagnetic radiation and containing a specific address temporal profile and possibly additional data. Routing generally involves a unit of active material that is programmed using one or more input beams or pulses of the electromagnetic radiation providing address (i.e., waveform-discriminating) and directional (i.e., pulse routing) information to the active material. During programming, a spatial-spectral grating is created by optical interference on or in the active material of the input pulses encoding the address and directional information pertinent to the data pulse.

Abstract: In an image processing circuit, a color correction section, an area determination section and a MTF correction section each comprises a rewritable device (for example, field programmable gate array (FPGA) circuit) including a plurality of line memories (FIFO memories). A CPU reconstructs the image processing function of the FPGA circuit by using setting information and a processing program stored in the ROM in accordance with the set image processing condition such as the processing speed priority mode or the image quality priority mode.

Abstract: An optical recording/reproducing apparatus having excellent resistance against vibration and noise is provided. In recording, coherent light is polarization-modulated with a spatial light modulator to generate signal light and reference light whose polarization directions are crossed at right angles with each other. The signal light permeates a polarizing beam splitter, and is incident to a quarter wavelength plate. The reference light passes through a passing hole, is diffused by a light diffuser and is incident to the quarter wavelength plate. The reference and signal light are converted into circularly polarized light which revolve in directions opposite to each other and condensed by a condenser lens, and then a predetermined area of an optical recording medium is irradiated with the reference and signal light. Thus, the reference and signal light are generated by modulating the incident light from the same light source and are coaxially incident to the polarizing beam splitter.

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 authentication system using a correlator that correlates an input with a reference wherein at least one of the input and reference comprises a phase volume mask having structures, preferably points, that are each less than about six microns in size and can have an aspect ratio (AR) greater than 1:1 so as to produce a phase encoded random pattern having millions of combinations in a mask that is as small as one square millimeter. The random pattern can be convolved with a second pattern, such as a biometric pattern, to produce a phase convolved mask. The correlator preferably is a nonlinear joint transform correlator that can use “chirp” encoding to permit the input to be located in a different plane than the reference. The correlator optically Fourier transforms images of the reference and input that are thereafter nonlinearly transformed and inverse Fourier transformed by a processor to determine the presence or absence of a correlation spike indicative of authenticity.

Abstract: A pixel element for a 3D display, wherein multiple substantially collimated controllable light beams are emitted in multiple directions, with each light beam associated with a predetermined viewing direction. A set of substantially point type sources are individually addressable and are arranged in a line. The light sources are serially addressed; and the light from each source is imaged in a collimated light beam and deflected in a predetermined individual deflection direction.

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: An apparatus includes recording reference optics, recording signal optics, and reproducing reference optics. The recording reference optics supplies a recording reference light beam to a recording medium, and the recording signal optics supplies a signal light beam, which is modulated in accordance with image data, to the recording medium. The signal light beam and the recording reference light beam produce an interference pattern within the recording medium. The reproducing reference optics supplies a reproducing reference light beam, which propagates in an opposite direction of the recording reference light beam, to the recording medium. The reproducing reference light beam generates a phase conjugate wave from a refractive-index grating of the interference pattern, and the phase conjugate wave is split from an optical path of the signal light beam to image a dot pattern with the phase conjugate wave. Also, a photo-detector detects the dot pattern to reproduce image data.

Abstract: The present invention provides a solution to the needs described above through a system and method for holographic storage. The system comprises a laser light source, a first beam splitter for splitting a light beam into an object and reference beam, an elliptical reflector with a first and second focal point, a reflector rotatable about a first axis and a second axis, a pattern encoder, and a holographic storage medium. The reflector is located at the first focal point of the elliptical mirror, and the holographic storage medium is located at the second focal point of the elliptical mirror.

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: 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: An integrated broadband polarization controller is based on planar waveguide technology. The integrated broadband polarization controller emulates the polarization control function of an existing single channel polarization controller in a device that can be built in planar waveguide technology, and is expanded from single channel operation to broadband channel operation by designing the control degrees of freedom to be wavelength selectively addressable.

Abstract: In a second exposure following a first exposure, a light transmitting-screening pattern of a second original mask is exposed on a hologram material by using a second object light to be irradiated on a hologram material though the second original mask and a second reference light to be irradiated on a hologram material to be irradiated on the hologram material not through the second original mask, and by changing a second phase difference between the second object light and the second reference light in a position in an optical path from a light source to the hologram material so that a first phase difference between the first object light and the first reference light may differ from the second phase difference.

Abstract: This invention encompasses a method for the manufacture and rapid assembly of large screen fiber optic displays (1, 2) containing a very large number of individual fibers (thousands to hundreds of thousands, or more). The display surface is modularized into relatively small, thin, interchangeable, injection-molded square or rectangular tiles (3) to simplify manufacture and assembly. The hundreds of fibers (7) required for each tile (3) are machine-configured into a plurality of flat, flexible fiber optic ribbon cables (4), each cable (4) comprised of a planar geometric array of optical fibers (7) embedded in a thin adhesive matrix (8). The image emission end of each flat, flexible fiber optic cable (4) is a fiber manifold (20) joined to an injection-molded thermoplastic array of light guides (11), each fiber terminating in a single light guide or emitter (12).

Abstract: The present invention provides a solution to the needs described above through a system and method for holographic storage. The system comprises a laser light source, a first beam splitter for splitting a light beam into an object and reference beam, an elliptical reflector with a first and second focal point, a reflector rotatable about a first axis and a second axis, a pattern encoder, and a holographic storage medium. The reflector is located at the first focal point of the elliptical mirror, and the holographic storage medium is located at the second focal point of the elliptical mirror.

Abstract: A synthetic aperture system for producing a non-periodic pattern in a region of overlap. The system includes a source of electromagnetic radiation producing a plurality of electromagnetic beams, a plurality of beam controllers positioned to receive a respective one of the plurality of electromagnetic beams and direct the respective electromagnetic beam into the region of overlap; and a system controller in electrical communication with each of the plurality of the beam controllers. Each beam controller controls at least one of the phase, amplitude and polarization of a respective one of the plurality of electromagnetic beams in response to control signals from the system controller. The result is a non-periodic pattern formed within the region of overlap by the interference of a plurality of electromagnetic beams in response to the control signals from the system controller. The invention also relates to a method for producing a non-periodic pattern in a region of overlap.

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: A method of writing holograms includes: numbering sections in sequence, where each section has a spatial projection onto a holographic medium; and writing at least one hologram in each of the sections in sequence. Writing in two sections with adjacent spatial projections provides a substantially uniform exposure level for a sequentially subsequent section with a spatial projection that overlaps the two sections.

Abstract: An image information displaying system comprises a transparent support, a hologram screen attached to the transparent support, a radiation unit for radiating image information on the hologram screen, a sensor for detecting the ambient condition within the viewing angle of the hologram screen, and a controller for controlling the radiation unit based on the signal from the sensor. The image information displaying system, which is inexpensive, long in service life, superior in eye-catching effect and low in running cost, consumes less energy and is controlled by a central control unit connected thereto through a communication line. The lower-end of the hologram screen is 80 to 180 cm from the floor level.

Abstract: A system for converting an image into a hologram formed from diffraction gratings includes obtaining image data for each pixel in an image to be converted, putting it into digital form and using the image data to control portions of a laser beam split into a reference beam and at least one object beam. The diffraction gratings are formed by an interference pattern of a reference beam and at least one object beam intersecting on the surface of a photoresist material on a pixel-by-pixel basis. Modulation of at least one object beam and adjustment of the angle at which that beam interferes with the reference beam on the photoresist material is used to reflect image data for each pixel of the image being converted into a hologram consisting of diffraction gratings.