Abstract: Described are a method and apparatus for high-speed phase shifting of an optical beam. A transparent plate having regions of different optical thickness is illuminated by an optical beam along a path of incidence that extends through the regions. The transparent plate can be moved or the optical beam can be steered to generate the path of incidence. The optical beam exiting the transparent plate has an instantaneous phase value according to the region in which the optical beam is incident. Advantageously, the phase values are repeatable and stable regardless of the location of incidence of the optical beam within the respective regions, and phase changes at high modulation rates are possible. The method and apparatus can be used to modulate a phase difference of a pair of coherent optical beams such as in an interferometric fringe projection system.

Abstract: In known light modulation means, complex phase and amplitude values for modulating light waves are implemented and modulated either separately by two different light modulation means or a light modulation means having two layers of double-refracting materials, leading to increased expenses for material and adjustment. A new device is disclosed that simplifies the modulation of light waves in phase and amplitude in a single light modulation means made of double-refracting material. In a device having regularly disposed, controllable light-modulated elements having a double-refracting material for complex modulation of coherent light waves, and a modulation controller controlling the force-induced alignment of the optical axes of the molecules of the double-refracting material, means are provided for independently aligning the optical axes of the molecules in the light-modulating elements in two dimensions. The alignment can take place by electrical, magnetic, or optical acting means.

Abstract: A digital holography device includes a light source that emits light, the light source being provided for supply of object light beams formed by radiation, transmission, scattering, reflection, or diffraction of the emitted light from a subject, an array device that splits the light emitted from the light source into two kinds of reference light beams having different phases in a plane perpendicular to a direction in which the light emitted from the light source travels, a CCD camera having an image-capturing plane on which two kinds of interference fringe patterns are recorded, the interference fringe patterns being formed by interferences between the two kinds of reference light beams, and the object light beams, and an image reconstruction device that generates a reconstructed image of the subject from the two kinds of interference fringe patterns recorded on the image-capturing plane.

Abstract: The present invention provides systems of recording holograms that reduce the writing time, increase the diffraction efficiency, improve the resolution, or restitute color. These systems are well suited for use with an updateable 3D holographic display using integral holography and photorefractive polymer.

Abstract: According to one embodiment, a data reproducing apparatus includes a data recording medium, light source unit, light application unit, photodetector unit and control unit. An address mark string including address marks is formed on the data recording medium. The address marks are spaced from each other by a distance depending on address data. The light application unit is configured to split the light beam into a first branch light beam and a second branch light beam and apply the first and second branch light beams to the address mark string at different angles. The photodetector unit is configured to detect first reflected light beams and second reflected light beams from the address mark string to generate image data. The first and second reflected light beams result from the first and second branch light beams, respectively. The control unit is configured to reproduce address data based on the image data.

Abstract: A complex spatial light modulator includes a polarization-phase modulator for separating an incident beam into a first beam having a first polarization and a first phase, and a second beam having a second polarization and a second phase, and for outputting the first beam and the second beam; and a beam synthesizer including a prism structure formed of an optical anisotropic material having a first refractive index with respect to the first beam having the first polarization and having a second refractive index, different form the first refractive index, with respect to the second beam having the second polarization, where the beam synthesizer combines the first beam and the second beam.

Abstract: A holographic projection device comprises for the reconstruction of scenes at least one light source which emits sufficiently coherent light for the generation of a wave front. Further, the projection device comprises at least one light modulator device containing modulation element, said projection device being of a two-dimensional design. The light modulator device and a scanning element are combined such that the light emitted by the scanning element only scans one one-dimensional arrangement of modulation elements of the two-dimensional light modulator device at a time.

Abstract: A hologram display module 100 that a large number of light source elements and a large number of spatial light modulation elements overlapped with the light source elements are arranged: wherein the light source element is arranged quadratically in area of predetermined height width to comprise each of scanline forming a line in height direction; openings of the light source elements are placed each other in distinct position horizontally; the light source elements produce lights that are coherence spatially each other, respectively; the spatial light modulation element spatially modulates light from the light source element for independence, respectively.

Abstract: The present invention relates to a reference beam coupler for an apparatus for reading from and/or writing to holographic storage media, to a multiplexing scheme using the reference beam coupler, and to an apparatus for reading from and/or writing to holographic storage media using such reference beam coupler or multiplexing scheme. According to the invention, the reference beam coupler has: a substrate; one or more optical fibers passing through the substrate for coupling one or more reference beams; and a reflective area on the substrate for reflecting an object beam, which serves as a Fourier filter for the object beam.

Abstract: Holographic display apparatuses are provided. The holographic display apparatus may include a light source module generating coherent light, at least two input optical systems converging the light generated from the light source module on at least two converging points, an output optical system mixing the lights provided from the at least two input optical systems to provide a hologram image, and a spatial light modulating module modulating the light.

Abstract: A photorefractive composite, a spatial light modulator and a hologram display device using the same include at least one carborane compound expressed as the following Chemical Formulae 1A through 1C: wherein the photorefractive composite exhibits photoconductivity and optical nonlinearity.

Abstract: A photorefractive composite, a spatial light modulator and a hologram display device using the same include at least one carborane compound expressed as the following Chemical Formulae 1A through 1C: wherein the photorefractive composite exhibits photoconductivity and optical nonlinearity.

Abstract: A hologram master having a hologram image recorded thereon is brought into intimate contact with a surface of a hologram recording medium containing a photosensitive material directly or via a refractive index adjuster. The hologram image is made to have continuous parallax in at least a first direction with a movement of an eyepoint along the first direction with respect to a normal line when the hologram master is illuminated at a predetermined angle. First laser light is applied onto the hologram master and the hologram recording medium via a diffusion plate configured to diffuse incident light in a second direction. Second laser light is applied onto the hologram recording medium via the hologram master simultaneously with the first laser light. The hologram image recorded on the hologram master and first additional information are recorded on the hologram recording medium.

Abstract: A light irradiation device includes: a focus servo control unit including a light source, a spatial light modulating unit, and a light irradiating unit, for focus servo control so that the ideal focal position of light via an objective lens is such that distance between an ideal focal position and a hologram recording medium surface is smaller than distance from the surface to the lower layer side face of the recording layer, and the focal position of light via the objective lens is constant at the ideal focal position; an objective-lens/relay-lens distance adjusting unit to adjust distance between the objective lens and a relay lens close to the objective lens; a light reception unit to receive marker light; and a constant distance control unit to control the objective-lens/relay-lens distance adjusting unit based on error between the ideal position of the marker light, and the actual position of the marker light.

Abstract: The present invention relates to a light modulating device, comprising a SLM and a pixelated optical element, in which a group of at least two adjacent pixels of the SLM in combination with a corresponding group of pixels in the pixelated optical element form a macropixel, the pixelated optical element being of a type such that its pixels comprise a fixed content, each macropixel being used to represent a numerical value which is manifested physically by the states of the pixels of the SLM and the content of the pixels of the pixelated optical element which form the macropixel.

Abstract: A hologram reproducing apparatus includes a first reference light path leading laser light from a laser light source so that a hologram recording medium is irradiated with first reference light; a diffracted light path leading diffracted light, generated from the hologram recording medium by irradiation with the first reference light, to a light receiving element having a plurality of pixels; and a second reference light path leading second reference light, having the same polarization direction as that of the diffracted light, from the laser light source to the light receiving element. The second reference light path is provided with a phase modulating element so that the phase difference between the diffracted light and the second reference light in a light receiving surface of the light receiving element is adjusted within a predetermined range.

Abstract: A modular routing node includes a single input port and a plurality of output ports. The modular routing node is arranged to produce a plurality of different deflections and uses small adjustments to compensate for wavelength differences and alignment tolerances in an optical system. An optical device is arranged to receive a multiplex of many optical signals at different wavelengths, to separate the optical signals into at least two groups, and to process at least one of the groups adaptively.

Abstract: A holographic direct-view display system uses holographic integral imaging techniques that is an auto stereoscopic way to reproduce parallax and occlusion. The display is not resolution limited and is scalable to display life size images if desired. The system can be used to transmit 3D depictions of a scene at video and sub-video rates as well as other information, such as images of documents or computer generated images. The images may be captured, transmitted and displayed in real-time (or near real-time) for telepresence or stored for time-shifted display. The system combines integral holography, a pulsed laser to record the hologram at high speed and a dynamic refreshable holographic material such as a photorefractive polymer as a recording media. The system uses techniques to write, read and erase the updateable hologram that allow the holographic material, hence direct-view display to remain stationary throughout each of the processes for continuous presentation of the hologram to the audience.

Abstract: An apparatus for reading a data page from and/or writing a data page to a holographic storage medium includes a common aperture arrangement of one or more reference beams and an object beam or a reconstructed object beam. One or more spatial light modulators are provided for generating the one or more reference beams by modulating a light beam with a modulation pattern having a spatial frequency higher than the spatial frequency of the data page.

Abstract: The present invention provides a holographic storage apparatus comprising a polarizing beam splitter configured to split an incoming beam into an object beam and a reference beam; a first spatial light modulator configured to modulate the object beam with an array of data; a second spatial light modulator configured to phase modulate the reference beam with an orthogonal phase function; a holographic medium configured to record an interference pattern between the modulated object beam and the modulated reference beam; a first image sensor configured to read an image of the modulated object beam; and a second image sensor configured to read an image of the modulated reference beam.

Abstract: A method of recording holographic information includes recording a hologram mark and a homogeneous mark in a holographic data storage medium with a volume to alternatively locate the hologram mark and the homogeneous mark. The hologram mark has a varied refractive index distribution due to constructive/destructive interferences between two light beams and indicates information, while the homogeneous mark has a more uniform refractive index distribution than the hologram mark.

Abstract: An image projector having one or more broadband lasers designed to reduce the appearance of speckle in the projected image via wavelength diversification. In one embodiment, a broadband laser has an active optical element and a nonlinear optical element, both located inside a laser cavity. The broadband laser generates an output spectrum characterized by a spectral spread of about 10 nm and having a plurality of spectral lines corresponding to different spatial modes of the cavity. Different individual spectral lines effectively produce independent speckle configurations, which become intensity-superimposed in the projected image, thereby causing a corresponding speckle-contrast reduction.

Abstract: An apparatus includes a low-coherent light source configured to emit an electromagnetic wave; a spatial light modulator configured to modulate a wavefront of the electromagnetic wave; an interferometer including a movable mirror to set a depth of a medium to be irradiated by the electromagnetic wave and a beam splitter configured to the electromagnetic wave into a reference beam and an object beam; a detector to detect information about an interference pattern formed by the object beam coming from the medium via the beam splitter and the reference beam reflected by the movable mirror; and a controller configured to control the spatial light modulator, based on the information, to form a modulated wavefront for irradiating the medium.

Abstract: A holographic storage system having an improved data page quality is described. The holographic storage system includes a special optical filter or a special light source for emphasizing the high frequency components of a reference beam and/or an object beam. This is achieved by an optical filter arranged in a Fourier plane, which has a higher attenuation at the center than at the edge. Alternatively, an adapted light source for generating the reference beam and/or the object beam is arranged in a Fourier plane. The light beam emitted by the light source has a higher intensity close to the edge than at the center.

Abstract: The present invention provides a holographic storage apparatus comprising a polarizing beam splitter configured to split an incoming beam into an object beam and a reference beam; a first spatial light modulator configured to modulate the object beam with an array of data; a second spatial light modulator configured to phase modulate the reference beam with an orthogonal phase function; a holographic medium configured to record an interference pattern between the modulated object beam and the modulated reference beam; a first image sensor configured to read an image of the modulated object beam; and a second image sensor configured to read an image of the modulated reference beam.

Abstract: A recording/playback apparatus includes a light-generating and intensity-modulating section for generating signal light and reference light to be shined on a hologram recording medium and a phase modulating section for performing phase modulation on the signal light and the reference light on the basis of a pixel unit by using the first to nth phase modulation levels. For the phase modulation on the reference light, all pixels corresponding to the reference light are divided and set using random phase units, each having a predetermined pixel array pattern having at least two pixels, the number of pixels corresponding to each of the first to nth phase modulation levels in each random phase unit is common to the random phase units, and the array pattern of the pixels corresponding to the first to nth phase modulation levels is random for each random phase unit.

Abstract: The present invention relates to a holographic storage system, and more specifically to a method for pixel detection in a coaxial holographic storage system. In a holographic storage system according to the invention, with a coaxial arrangement of an object beam and a reference beam the bright pixels within the object beam have a phase shift of essentially ? relative to the reference beam. For readout of a data page contained in a reconstructed object beam a detector detects an interference pattern generated by the interference between the reference beam and the reconstructed object beam.

Abstract: An apparatus for reading from and/or writing to holographic storage media is described, and more specifically an apparatus for reading from and/or writing to holographic storage media with two or more reference beams that overlap inside the holographic storage medium for reading and/or writing a single hologram. The two or more reference beams are mutually incoherent during reading and/or writing.

Abstract: The present invention relates to a three-dimensional light modulator, of which the pixels are combined to form modulation elements. Each modulation element can be coded with a preset discrete value such that three-dimensionally arranged object points can be holographically reconstructed. The light modulator according to the invention is characterized in that assigned to the pixels of the modulator are beam splitters or beam combiners which, for each modulation element, combine the light wave parts modulated by the pixels by means of refraction or diffraction on the output side to form a common light beam which exits the modulation element in a set propagation direction.

Abstract: A optical apparatus (201) for use in an laser imaging system (200) is provided. The optical apparatus (201) includes one or more optical elements (215) that are configured to create an intermediate image plane (217) in the laser imaging system (200). A diffractive optical element (216) is then disposed at the intermediate image plane (217) to reduce speckle. The diffractive optical element (216) includes a periodically repeating phase mask (218) that can be configured in accordance with steps, vortex functions, Hermite-Gaussian functions, and so forth. Smooth grey-level phase transitional surface (337) can be placed between elements (333,334) to improve brightness and image quality. The periodically repeating phase mask (218) makes manufacture simple by reducing alignment sensitivity, and can be used to make applicable safety standards easier to meet as well.

Abstract: A holographic image projection system for projecting an image at an acute angle onto a surface includes: a spatial light modulator (SLM) to display a hologram; an illumination system to illuminate the displayed hologram; projection optics to project light from the illuminated displayed hologram onto the surface at an acute angle form the image; and a processor having an input to receive input image data for display and an output to provide hologram data for the SLM, wherein the processor is configured to: input image data and convert this to target image data; generate from the target image data hologram data for display as a hologram on the SLM to reproduce a target image; and wherein the target image is distorted to compensate for the projection of the hologram at an acute angle to form the image.

Abstract: A holographic data storage system that includes a write head that includes a pixellated spatial light modulator and a separate or integral phase mask that varies the phase depending on the location in the phase mask that light passes through. The phase variation can be changed over time in a random, pseudo-random, or predetermined fashion. The spatial light modulator and phase mask can be implemented in a liquid crystal SLM (nematic, ferroeleletric, or other), in a DMD SLM, in a magneto-optical SLM, or in any other suitable manner.

Abstract: The present disclosure relates to a digital hologram display device in which the 0th diffraction component is removed for optimizing the reproduction and replay of the three-dimensional hologram video data. The present disclosure suggests a digital hologram image display device comprising: a pattern generator generating holography interference patterns; a spatial light modulator receiving the holography interference patterns from the pattern generator and represent the holography interference patterns; a light source positioning at one side of the spatial light modulator and illuminating a reference beam to the spatial light modulator; an optical device controlling the reference beam to be raditated onto a whole surface of the spatial light; and a diffusion sheet having at least 20% of Haze value and disposed between the light source and the spatial light modulator.

Abstract: A holographic storage system for reading a hologram stored on a holographic storage medium. The system comprises: storage medium holding means; a spatial light modulator (SLM) for encoding a reference beam with a code pattern; a detector; and a servo control unit for determining a misalignment of the reference beam and the storage medium from the detected image and for acting upon the SLM to shift the code pattern. A method of reading a hologram stored on a holographic storage medium comprising: a) encoding a reference beam with a code pattern created by a spatial light modulator (SLM); b) detecting an image of the reconstructed hologram; c) determining a misalignment of the reference beam and the storage medium from the detected image; and d) shifting the code pattern on the SLM based at least in part on the misalignment.

Abstract: A method for holographic data recording and simultaneous data readout without requiring additional optical power for readout illumination is provided. The method comprises reflecting a transmitted portion of a data light beam or of a reference light beam used for holographic recording of data in a holographic data storage medium. The reflected beam is configured to illuminate the holographic data storage medium from the opposite side with a polarization orthogonal to that of the recording beams, such that it provides a counter-propagating readout beam for real-time readout of currently being recorded hologram. Readout beam may also be configurable for accessing any one of the at least one previously recorded holograms. Systems using the methods of the invention are also provided.

Abstract: A holographic memory device is described which records and reproduces binary image data by irradiating a holographic recording medium with signal light and reference light. The holographic memory device includes a system for aligning polarization of the signal light and reference light on the holographic recording medium by guiding the signal light and the reference light to be coaxially opposed. The holographic memory device further includes a random-phase modulation multiplex recorder and spatial-shift multiplex recorder that, together with the system for aligning polarization, significantly enhances recording density and improves recording capacity.

Abstract: A reproducing device for performing reproduction regarding a hologram recording medium where a hologram page is recorded in accordance with signal light, by interference between the signal light where bit data is arrayed with the information of light intensity difference in pixel increments, and reference light, includes: a reference light generating unit to generate reference light irradiated when obtaining a reproduced image; a coherent light generating unit to generate coherent light of which the intensity is greater than the absolute value of the minimum amplitude of the reproduced image, with the same phase as the reference phase within the reproduced image; an image sensor to receive an input image in pixel increments; and an optical system to guide the reference light to the hologram recording medium, and also guide the obtained reproduced image according to the irradiation of the reference light, and the coherent light to the image sensor.

Abstract: Provided is a holographic display that realizes a high-resolution three-dimensional (3D) image as a spatial light modulation panel system having a fast response time and enabling the formation of high-density pixels is developed. The holographic display includes, a spatial light modulator using a polymer thin film or a dielectric thin film that enable the formation of high-density pixels and has a fast response time, a fine displacement panel system sequentially moving the spatial light modulator in synchronization with a hologram fringe signal, and an optical system including a coherent light source, a spatial light modulation panel system, and an optical element that are efficiently disposed. The holographic display has a feature that realizes a high-resolution 3D image in a scheme that integrates and displays an image while sequentially moving a spatial light modulator simply or overlaps a hologram fringe pattern.

Abstract: A modular routing node includes a single input port and a plurality of output ports. The modular routing node is arranged to produce a plurality of different deflections and uses small adjustments to compensate for wavelength differences and alignment tolerances in an optical system. An optical device is arranged to receive a multiplex of many optical signals at different wavelengths, to separate the optical signals into at least two groups, and to process at least one of the groups adaptively.

Abstract: A hologram recording apparatus includes a signal-beam spatial light modulating section, a reference-beam spatial light modulating section, and a control unit. A signal beam pattern generates a signal beam. A reference beam pattern generates a reference beam. The control unit controls the shapes of the two beam patterns. A data-recording signal beam pattern is displayed on the signal-beam spatial light modulating section and a data-recording reference beam pattern is displayed on the reference-beam spatial light modulating section so that a data-recording hologram is formed in a predetermined area of a holographic recording medium. An encryption signal beam pattern for encrypting the data-recording hologram is displayed on the signal-beam spatial light modulating section and an encryption reference beam pattern is displayed on the reference-beam spatial light modulating section so that an encryption hologram is formed in the same area as the predetermined area of the holographic recording medium.

Abstract: An imaging system (200) includes a plurality of laser sources (201) configured to produce a plurality of light beams (204). One or more optical alignment devices (220) orient the light beams (204) into a collimated light beam (205). A light modulator (203) modulates the collimated light beam (205) such that images (206) can be presented on a display surface (207). Speckle is reduced with an optical feedback device (221) that causes the laser sources (201) to operate in a coherence collapsed state. Examples of optical feedback devices (221) include partially reflective mirrors and beam splitter-mirror combinations.

Abstract: Various embodiments of the present invention relate to systems that can be used as holograms and can be electronically controlled and dynamically reconfigured to generate three-dimensional motion picture images. In one embodiment, a dynamically reconfigurable hologram (1200) comprises a phase-control layer (1202) including a two-dimensional array of phase-modulation pixels (1212). The hologram also comprises an intensity-control layer (1204) including a two-dimensional array of intensity-control pixels (1214). One or more three-dimensional motion pictures can be produced by electronically addressing the individual phase-modulation pixels and intensity-control pixels in order to phase and control the intensity of light emanating from pixels of the hologram.

Abstract: An optical beam with the same amplitude distribution and phase distribution as those of the signal beam used for recording is radiated to the hologram recording medium via an optical system of the signal beam prior to reproduction so that the optical beam with the amplitude and phase of the reference beam upon recording is generated through diffraction. A wavefront sensor detects the wavefront configuration of the diffraction beam and obtains preliminarily the suitable wavefront of the reference beam for reproduction. The wavefront control element preliminarily corrects the wavefront of the reference beam to an optimum wavefront.

Abstract: The present invention discloses a wavelength-multiplex and space-multiplex holographic storage device, which comprises a storage medium, a plurality of signal light beams and at least one reference light beam. The signal light beams have different wavelengths and illuminate the storage medium. The reference light beam illuminates the storage medium and interferes with the signal light beams to form a plurality of interference patterns. The interference patterns are respectively stored on different-depth storage layers of the storage medium. The present invention not only has a high access rate but also has a large storage capacity.

Abstract: A hologram recording method includes generating light of a pattern in which a plurality of unit blocks, which include at least one pixel and express luminance, are arrayed, the pattern being sectioned into a region of a signal beam and a region of a reference beam, and being generated such that the region of the reference beam includes a plurality of unit blocks whose numbers of pixels are different; collecting the generated light at a common optical system, and illuminating it onto an optical recording medium; and recording, as a hologram, data which the signal beam expresses.

Abstract: Disclosed is a color filter with parallel, vertical color strips of the RGB base colors associated with the image separating means, the color strips repeating horizontally within the color filter in periodic fashion. The light modulator contains a sequence of two registered holograms for each base color interlaced into six pixel columns for a left observer eye and for a right observer eye, and the sequence is repeated horizontally in periodic fashion. The periods of the color filter and the hologram are arranged relative to one another with the same degree of expansion, with a color strip and at least two pixel columns with holograms of the base color of the color strip are associated with a separating element.

Abstract: In a holographic information recording and reproducing apparatus, an optical fiber guides a reference beam toward a recording medium for holographic recording, and a precision rotator is turned, so that the reference beam is incident on the recording medium at different angles and interferes with a data-carrying signal beam to complete the recording of holographic information on the recording medium. To reproduce the holographic information, the optical fiber guides a reading beam, and the reading beam is incident on the recording medium at an angle the same as the reference beam for the recording to reproduce the holographic information stored on the recording medium. With the optical fiber and the precision rotator, a simplified light path system and a wide range of incident angles for the reference and reading beams may be achieved, and the transmissive, reflective, and 90-degree holographic storage techniques may be integrated in one single apparatus.

Abstract: Various embodiments related to rear-projection image display are disclosed. For example, one disclosed embodiment provides a projector for projecting an image and a screen configured to display the image. The screen comprises a filter layer having a light reception side and an image display side. The filter layer includes an array of trapezoidal transmissive elements and an array of trapezoidal absorption elements, where a wider base of each of the trapezoidal transmissive elements faces the light reception side of the filter layer, and where a wider base of each of the trapezoidal absorption elements faces the image display side of the filer layer.

Abstract: A system and method that synchronizes a spatial light modulator (SLM) with a pulsed laser to record a hologram at the repetition rate of the pulsed laser for applications including holographic displays and data storage. The color channel capability of a SLM is utilized to effectively increase the write throughput when the pulsed laser repetition rate LR exceeds the SLM's image refresh rate R. The hogels are encoded on the color channels and concatenated to form a sequence of color images such that the write throughput is equal to the repetition rate LR up to a maximum of N*R. The invention effectively extends the capability and continued viability of existing inexpensive SLMs.

Abstract: An imaging system (200) includes a plurality of laser sources (201) configured to produce a plurality of light beams (204). One or more optical alignment devices (220) orient the light beams (204) into a collimated light beam (205). A light modulator (203) modulates the collimated light beam (205) such that images (206) can be presented on a display surface (207). Speckle is reduced with an optical feedback device (221) that causes the laser sources (201) to operate in a coherence collapsed state. Examples of optical feedback devices (221) include partially reflective mirrors and beam splitter-mirror combinations.