Abstract: An apparatus and a method for reading from and/or writing to holographic storage media using a coaxial arrangement of an object beam and one or more reference beams or a coaxial arrangement of a reconstructed object beam and one or more reference beams is proposed. A focus of the one or more reference beams within a holographic storage medium is shifted along the optical axis relative to a focus of the object beam or the reconstructed object beam.

Abstract: The present invention relates to a lens system for an apparatus for reading from and/or writing to holographic storage media, and more specifically to a lens system optimized for an apparatus with a coaxial common aperture arrangement of an object beam and a reference beam. According to the invention, the lens system, which Fourier transforms an object beam and focuses a reference beam into a hologram layer of a holographic storage medium, and which focuses a servo beam onto a servo area of the hologram layer, includes a moving part acting on the object beam, the reference beam and the servo beam, and a fixed part acting only on the servo beam.

Abstract: An apparatus for reading from and/or writing to transmission type holographic storage media is proposed, and more specifically a coaxial type apparatus for reading from and/or writing to transmission type holographic storage media with two or more reference beams, which has an improved Signal to Noise Ratio. The apparatus has a coaxial arrangement of two or more reference beams and an object beam or a reconstructed object beam. The reference beams are arranged on a circle around the object beam or the reconstructed object beam in a Fourier plane of the apparatus behind the holographic storage medium. A mirror is located in or close to this Fourier plane, which is designed such that it reflects the object beam or the reconstructed object beam without reflecting the reference beams.

Abstract: An apparatus for reading from or writing to holographic storage media, and more specifically a common aperture type apparatus for reading from or writing to holographic storage media with multiple reference beams having a reduced noise. In a common aperture type apparatus for reading from or writing to a holographic storage medium using shift-multiplexing, with a coaxial arrangement of two or more reference beams and an object beam or a reconstructed object beam, the reference beams being arranged around the object beam or the reconstructed object beam in a storage layer of the holographic storage medium. Each of the reference beams is located essentially halfway between two adjacent central peaks of shift-multiplexed holograms.

Abstract: The present invention relates to a coaxial type apparatus for reading from and/or writing to holographic storage media with multiple reference beams. The invention further relates to a beam generator and a filter for use in such an apparatus. According to the invention, in an apparatus for reading from and/or writing to a holographic storage medium, with a coaxial arrangement of three or more focused reference beams and an object beam or a reconstructed object beam, the foci of the focused reference beams are arranged on a circle around the object beam in a Fourier plane of the apparatus. A beam generator generates the three or more reference beams from an incoming reference beam. A filter low-pass filters the object beam and rotates the polarization of the three or more reference beams.

Abstract: The present invention relates to a holographic storage system, and more specifically to a holographic storage system using a phase spatial light modulator. According to the invention a holographic storage system with a phase SLM for imprinting a 2-dimensional phase data pattern onto an object beam includes a common path interferometer for converting the phase data pattern of the object beam into an intensity data pattern.

Abstract: The present invention relates to an apparatus for reading from and/or writing to holographic storage media, and more specifically to an apparatus for reading from and/or writing to holographic storage media having an apodization filter. According to the invention, an apparatus for reading from and/or writing to a holographic storage medium, with a collinear split aperture arrangement of a reference beam and an object beam or a reconstructed object beam, includes an apodization filter for the reference beam.

Abstract: A head mounted display is disclosed that utilizes a single video display screen to transport images to both eyes. Multiple reflections are created by illuminating the display screen form a plurality of directions, or by illuminating the display screen with light beams of differing polarizations. The reflections of the display screen are focused in order to reduce the splitting volume and then redirected by a plurality of reflective surfaces located near the focal point of the display images. Different images may be sent to each eye of a user by interlacing multiple data streams for the display and linking each data stream with a specific illumination direction, or specific polarization.

Abstract: An apparatus and a method for reading from and/or writing to holographic storage media using a coaxial arrangement of an object beam and one or more reference beams or a coaxial arrangement of a reconstructed object beam and one or more reference beams is proposed. A focus of the one or more reference beams within a holographic storage medium is shifted along the optical axis relative to a focus of the object beam or the reconstructed object beam.

Abstract: An apparatus for reading from and/or writing to transmission type holographic storage media is proposed, and more specifically a coaxial type apparatus for reading from and/or writing to transmission type holographic storage media with two or more reference beams, which has an improved Signal to Noise Ratio. The apparatus has a coaxial arrangement of two or more reference beams and an object beam or a reconstructed object beam. The reference beams are arranged on a circle around the object beam or the reconstructed object beam in a Fourier plane of the apparatus behind the holographic storage medium. A mirror is located in or close to this Fourier plane, which is designed such that it reflects the object beam or the reconstructed object beam without reflecting the reference beams.

Abstract: The invention describes a collinear optical head for a reflection-type holographic recording medium, which is capable of obtaining an increased capacity. The optical head presented here allows for high capacity by combining holographic multiplexing methods, based on a shift and/or phase-coded reference beam, and/or scanned reference beam and/or angle and/or confocal addressing techniques. The parallel reading method and the format of the holographic recording medium ensure high-speed data transfer. Combined multiplexing is implemented in the system by means of a confocal optical arrangement that reduces crosstalk between adjacent holograms by filtering out object beams unintentionally reconstructed from non-addressed holograms.

Abstract: The present invention relates to an apparatus for reading from and/or writing to holographic storage media, and more specifically to a common aperture type apparatus for reading from and/or writing to holographic storage media with multiple reference beams having a reduced noise. In a common aperture type apparatus for reading from and/or writing to a holographic storage medium using shift-multiplexing, with a coaxial arrangement of two or more reference beams and an object beam or a reconstructed object beam, the reference beams being arranged around the object beam or the reconstructed object beam in a storage layer of the holographic storage medium, each of the reference beams is located essentially halfway between two adjacent central peaks of shift-multiplexed holograms.

Abstract: The present invention relates to a lens system for an apparatus for reading from and/or writing to holographic storage media, and more specifically to a lens system optimized for an apparatus with a coaxial common aperture arrangement of an object beam and a reference beam. According to the invention, the lens system, which Fourier transforms an object beam and focuses a reference beam into a hologram layer of a holographic storage medium, and which focuses a servo beam onto a servo area of the hologram layer, includes a moving part acting on the object beam, the reference beam and the servo beam, and a fixed part acting only on the servo beam.

Abstract: A head mounted display is disclosed that utilizes a single video display screen to transport images to both eyes. Multiple reflections are created by illuminating the display screen form a plurality of directions, or by illuminating the display screen with light beams of differing polarizations. The reflections of the display screen are focused in order to reduce the splitting volume and then redirected by a plurality of reflective surfaces located near the focal point of the display images. Different images may be sent to each eye of a user by interlacing multiple data streams for the display and linking each data stream with a specific illumination direction, or specific polarization.

Abstract: A method and apparatus for improving the quality of light emitted from an HMD lightsource. A backlight-type lightsource is disclosed that utilizes a reflective end-wall 17 to reflect light within the lightguide. Light emitted from an illumination source and reflected from the end-wall 17 combine within the lightguide to produce light with high contrast and homogeneity. A microprism array, consisting of microprisms of uniform height and equidistant spacing, is positioned along the bottom surface of the lightguide. A portion of the combined light incident upon the microprism array is reflected in a direction substantially perpendicular to the lightguide top surface, which comprises an aperture. Light having increased brightness and homogeneity passes through the aperture. Light incident upon the top surface outside of the aperture is reflected within the lightguide so that it may subsequently be transmitted through the aperture.

Abstract: The present invention relates to an apparatus for reading from and/or writing to holographic storage media, and more specifically to an apparatus for reading from and/or writing to holographic storage media having an apodization filter. According to the invention, an apparatus for reading from and/or writing to a holographic storage medium, with a collinear split aperture arrangement of a reference beam and an object beam or a reconstructed object beam, includes an apodization filter for the reference beam.

Abstract: Holographic storage system with multiple reference beams The present invention relates to a coaxial type apparatus for reading from and/or writing to holographic storage media with multiple reference beams. The invention further relates to a beam generator and a filter for use in such an apparatus. According to the invention, in an apparatus for reading from and/or writing to a holographic storage medium, with a coaxial arrangement of three or more focused reference beams and an object beam or a reconstructed object beam, the foci of the focused reference beams are arranged on a circle around the object beam in a Fourier plane of the apparatus. A beam generator generates the three or more reference beams from an incoming reference beam. A filter low-pass filters the object beam and rotates the polarization of the three or more reference beams.

Abstract: The invention describes a collinear optical head for a reflection-type holographic recording medium, which is capable of obtaining an increased capacity. The optical head presented here allows for high capacity by combining holographic multiplexing methods, based on a shift and/or phase-coded reference beam, and/or scanned reference beam and/or angle and/or confocal addressing techniques. The parallel reading method and the format of the holographic recording medium ensure high-speed data transfer. Combined multiplexing is implemented in the system by means of a confocal optical arrangement that reduces crosstalk between adjacent holograms by filtering out object beams unintentionally reconstructed from non-addressed holograms.

Abstract: The present invention relates to a holographic storage system, and more specifically to a holographic storage system using a phase spatial light modulator. According to the invention a holographic storage system with a phase SLM for imprinting a 2-dimensional phase data pattern onto an object beam includes a common path interferometer for converting the phase data pattern of the object beam into an intensity data pattern.

Abstract: The object of the invention is a high data density holographic data storage method. The holograms are written into the volumetric data storage layer or layers, and during the writing process the accurate places of holograms in the data carrier structure are determined by the intersection domain of the object and reference beam or beams, and during the reading process the selection of holograms simultaneously illuminated by the reference beam or beams, the read-out of the addressed hologram, and the suppressing of un-addressed holograms are carried out by a spatial filter located confocally with the addressed hologram and/or by satisfying the Bragg condition. The optical arrangement for recording and reading out holograms has three dedicated planes in confocal arrangements, where the addressed hologram is in the middle dedicated plane in the storage material, and in the two outer dedicated planes there are spatial filters. The optical arrangement is a 12f optical System consisting of three pairs of objectives.