Abstract: Provided is an apparatus and method for recording data on a holographic storage medium. The apparatus includes: a light a light processing unit comprising the holographic storage medium and a light modulator, and recording data on the holographic storage medium using a reference beam and a signal beam modulated by the light modulator; and a control unit controlling the light processing unit to record the data on the holographic storage medium, wherein the light modulator is arranged so that an image formed on a surface of the light modulator is shorter in a radial direction that is a scanning direction of the reference beam than in a tangential direction that is perpendicular to the radial direction.

Abstract: Provided are a holographic data storage medium and an apparatus and method for recording/reproducing holographic data using the same. The holographic data storage medium includes: a substrate; a holographic recording layer disposed on the substrate; and a cover layer covering the holographic recording layer. The holographic recording layer includes: a data recording region including a plurality of data layers to which data is recorded, the data recording region in which interference fringes due to first and second beams are formed in different data layers in a depthwise direction; and a layer discrimination region for providing discrimination between the data layers.

Abstract: An optical pickup of a holographic data recording/reproducing apparatus that emits light to a reflective holographic data storage medium in which a substrate, a reflection layer, a recording layer, and a cover layer are sequentially stacked, and receives the emitted light, the optical pickup including: a first light source unit to emit, during a recording operation, a signal beam having a first polarization and a reference beam having a second polarization perpendicular to the first polarization along the same optical path; and a main lens unit having a refractivity that varies according to a polarization of a passing light, so as to cause the signal beam to be reflected from the reflection layer then focused on a focal point, and to cause the reference beam to pass through the cover layer then be directly focused on the focal point

Abstract: A holographic storage medium includes a substrate; a cover layer to receive a first circular polarization beam having a first polarization direction and a second circular polarization beam having a second polarization direction orthogonal to the first polarization direction; a polarization beam splitting/reflective layer disposed between the substrate and the cover layer to reflect the first beam while maintaining the first polarization direction of the first beam, and to transmit the second beam; and a holographic recording layer disposed between the polarization beam splitting/reflective layer and the cover layer to record information as an interference pattern formed in the holographic layer by the first beam reflected by the polarization beam splitting/reflective layer and the second beam received by the cover layer.

Abstract: A holographic recording/reproducing apparatus that easily controls an incident angle of a reference beam and that is less sensitive to a tilt of a holographic recording medium, the holographic recording/reproducing apparatus including: a light source to emit a light; and an optical system to divide the emitted light into a reference beam and a signal beam, and to provide the reference beam and the signal beam to the holographic recording medium, wherein the optical system provides the signal beam to be incident on an upper surface of the holographic recording medium, and provides the reference beam to be guided along the inside of the holographic recording medium by reflection due to a refraction index difference between the holographic recording medium and the outside of the holographic recording medium.

Abstract: Provided are a holographic information recording/reproducing apparatus in which positions of books can be accurately ascertained in a holographic recording medium, and a method for seeking books in the same. The apparatus includes an aperture plate disposed in an optical path of a signal beam reproduced from a reference beam that is incident on a holographic recording medium, and having an opening for restricting a width of the signal beam; one or more photodetectors installed on a surface of the aperture plate along a circumference of the opening; and a book position calculator to calculate positions of one or more books from the output of the photodetectors, wherein a cross-section of the reference beam incident on the holographic recording medium is larger than the size of the one or more books.

Abstract: An apparatus and a method to record and/or reproduce holographic information includes a light source to generate a light beam, a first beam splitter to split the light beam generated by the light source into two light beams, a signal beam component to modulate one of the two split light beams into a signal beam having a two-dimensional signal pattern and to transmit the signal beam to the holographic recording medium, a reference beam component to transmit the other of the two split light beams as a reference beam to the holographic recording medium, a two-dimensional photodetector to detect the signal beam reproduced from the holographic recording medium, and an aperture to restrict the width of the signal beam, wherein while information is recorded and/or reproduced in one region of the holographic recording medium, the aperture is moved according to a rotation of the rotating holographic recording medium.

Abstract: A system for generating a reference beam angle control signal and a holographic information recording and/or reproducing apparatus including the system are provided. When record of a two-dimensionally (2D) modulated signal beam superposed in the same volume of a holographic medium is called a book, the system includes: a first photo-detector and a second photo-detector arranged to detect signal beams reproduced from first and second adjacent books disposed on both sides of a specific book that is to be reproduced from the holographic medium; and a signal processing unit arranged to obtain a reference beam angle control signal for controlling the incident angle of a reference beam emitted to the holographic medium using a differential signal between output signals of the first and second photo-detectors.

Abstract: A method and apparatus for improving quality of a signal reproduced from a holographic storage medium in which a hologram is recorded by interference between a signal beam and a reference beam. The signal-quality improving method includes determining a page crosstalk value, which is caused in a page that is to be reproduced from the holographic storage medium by an adjacent page to the page that is to be reproduced, on the basis of on-pixel crosstalk values caused by a plurality of on-pixels of the adjacent page; and removing the determined page crosstalk value from a reproduced signal of the page that is to be reproduced. Since an interpage crosstalk that occurs when multiplexing recording in the holographic storage medium is calculated, and is removed from a reproduced signal, the quality of the reproduced signal can be improved.

Abstract: Provided are an apparatus for retroreflecting reference beams and a holographic information recording/reproducing device employing the same. The apparatus for retroreflecting reference beams for use in a holographic information recording/reproducing device for recording/reproducing information on/from a holographic recording medium includes a lens focusing reference beams transmitted through the holographic recording medium at different incident angles with respect to the holographic recording medium to form spots at different positions in a focal plane; and a mirror disposed at the focal plane and retroreflecting the spots created by the lens toward the holographic recording medium.

Abstract: An apparatus to control the incident angle of a reference beam, includes a first lens element to allow the reference beam to be incident on a holographic recording medium, and a driving portion to provide the reference beam to the first lens element and to move in a direction perpendicular to an optical axis to change the incident position of the reference beam on the first lens element in a radial direction of the first lens element, wherein the incident angle of the reference beam incident on the holographic recording medium is determined according to the incident position of the reference beam in a radial direction of the first lens element.

Abstract: An optical recording medium in which interference patterns formed from interference between signal light and reference light are recorded as data and a recording/reproducing method and apparatus for the optical recording medium. The optical recording medium including at least a recording layer in which predetermined data is recorded, wherein a thickness of a portion of the recording layer is larger than a thickness of another portion of the recording layer, wherein data is recorded in the thicker region, and the additional information of a recording condition and/or a reproducing condition is recorded in the thinner region.