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: A hologram recording and/or reproducing apparatus, a hologram recording and/or reproducing method, and a hologram recording medium include a data processing unit to generate a data page which includes recording data and a reference page which includes predetermined patterns to prevent distortion of a signal from occurring when the data page is reproduced, and a light processing unit to record the data page and reference page on a hologram recording medium. The apparatus and method correct distortion and deformation that may occur in part of an image due to aberrations, enhancing compatibility between hologram recording and/or reproducing apparatuses.

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.