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: An apparatus for recording/reproducing holographic data and a method of adjusting a position of a recording layer. While an objective lens focusing first and second lights having different wavelengths on a holographic data storage medium including first and second reflective layers reciprocatingly moves in a direction of an optical axis, a focus movement unit, which moves a focus of the second light in the direction of the optical axis until a time difference between a first detection signal generated when the first light is reflected from the first reflective layer and a second detection signal generated when the second light is reflected from the second reflective layer becomes a value corresponding to a position of a desired recording layer, is controlled to move a focal position of the second light so that the focal position of the second light can be adjusted to the position of a desired recording layer.

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: A multi-wavelength micro holographic data recording and/or reproducing apparatus in which decentering of light beams having different wavelengths is compensated for, the apparatus including: at least two light sources emitting the light beams; at least two photodetectors respectively detecting the light beams reflected from an optical recording medium; and an optical system guiding the light beams emitted from the light sources to the optical recording medium along a common optical path and guiding the light beams reflected from the optical recording medium to corresponding photodetectors, wherein the optical system includes: an objective lens focusing a light beam on the optical recording medium; a common decenter compensation member provided on the common optical path to adjust traveling angles of the light beams; and an individual decenter compensation member provided on an individual optical path of a light beam of individual wavelength to adjust a traveling angle of the light beam.

Abstract: Provided are a method and apparatus for recording/reproducing holographic information. The apparatus for recording/reproducing holographic information includes an optical pickup which irradiates light on a holographic information storage medium and receives irradiated light, wherein the optical pickup comprises a focusing optical system having a numerical aperture (NA) during recording that is lower than the NA during reproduction.

Abstract: An optical deflector includes a driving mirror, which is driven to rotate and has a deflecting surface for deflecting an incident light. Gratings are formed on the deflecting surface, each grating having a shape that makes the intensities of light beams diffracted at a positive order and a negative order different from each other. A main scanning line formed by a trace of the deflected light according to the rotation of the driving mirror is a straight line. The optical deflector is used in an optical scanning apparatus with a light source. The optical scanning apparatus is utilized in an image forming apparatus for forming an electrostatic latent image onto an exposure object.

Abstract: A holographic data storage medium, and a method and an apparatus for recording/reproducing holographic data by using the medium includes a substrate; manifold reflective layer between which a part of a signal beam is capable of being reflected at least one time and then being emitted from the manifold reflective layer; and a holographic recording layer in which a plurality of information layers are capable of being formed in a depth direction of the holographic recording layer, wherein interference patterns of a rest of the signal beam and a reference beam constitute each of the plurality of information layers.

Abstract: A defect entry, including position information of a defective block of a reference information layer and state information indicating the defective state of blocks of the other information layers located adjacent to a perpendicular direction at a position of the defective block of the reference information layer, is recorded on a holographic information storage medium. A method of inspecting for a defect includes determining whether blocks in a reference information layer are defective, and determining whether blocks of the other information layers located adjacent to a perpendicular direction at a position of a defective block of the reference information layer are defective, based on a result of the defect determination of the reference information layer.

Abstract: A holographic information recording and/or reproducing apparatus includes a light pickup optical system and a recording power control unit. The light pickup optical system illuminates reference light and signal light onto an information storing medium. The recording power control unit controls the light pickup optical system such that recording power of the reference light is the same as that of signal light.

Abstract: A holographic information recording and/or reproducing apparatus includes: a light source to emit light; a polarization conversion device to form a polarized signal beam and an orthogonal polarized reference beam; an optical path forming optical system to separate the optical paths of the signal beam and the reference beam; a focus adjustment optical system disposed on the optical path of at least one of the signal beam and the reference beam, and to vary a position of a focus of at least one of the signal beam and the reference beam in a depth direction of the holographic information storage medium; an objective lens to focus the signal beam and the reference beam in the holographic information storage medium, and form an interference pattern to record information; and a 4f relay system disposed on an optical path between the focus adjustment optical system and the objective lens.

Abstract: A holographic information recording and/or reproducing apparatus including: a light source unit emitting reference light and signal light; a first optical path guiding unit guiding the lights to cross; a second optical path guiding unit including a first polarization converter located on an optical path of one of the reference and signal lights, a first polarization beam splitter located at a crossing point of the reference light and the signal light, an optical path converter guiding the reference light and the signal light so that they cross again, a second polarization converter located on an optical path of the signal light before the signal light crosses the reference light, and a second polarization beam splitter uniting the optical paths of the reference light and the signal light; and an objective lens unit illuminating the reference light and the signal light onto one side of a holographic information storage medium.

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: A holographic information recording and/or reproducing apparatus, including a light source to emit light; a polarization forming optical system to form a polarized signal beam and a polarized reference beam from the light emitted from the light source, wherein the polarized signal beam and the polarized reference beam are incident on a holographic information storage medium through an identical surface; a focusing optical system to focus the polarized signal beam and the polarized reference beam onto in the holographic information storage medium so that information is recorded by an interference pattern; and an adjustment optical system to set the focal positions of the polarized signal beam and the polarized reference beam, and to adjust a difference between a path of the polarized signal beam and a path of the polarized reference beam.

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 method and apparatus for recording and/or reproducing holographic data and a holographic information storage medium, wherein the apparatus for recording and/or reproducing holographic information includes an optical pickup emitting light onto a holographic information storage medium and receiving the emitted light. The optical pickup includes: a light source unit emitting a signal beam and a reference beam in a recording mode; and a focusing optical system focusing the signal beam and the reference beam on one focal point in the holographic information storage medium so that information can be recorded by using an interference pattern formed along a depth direction of the holographic information storage medium in the vicinity of the focal point, wherein the numerical aperture of the focusing optical system for the signal beam is different from the numerical aperture of the focusing optical system for the reference beam.

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: A holographic storage medium includes a hologram including data recorded in a plurality of pages in a superimposed fashion by interference of a signal beam and a reference beam, and an additional page recorded between two adjacent pages in the plurality of pages, wherein a portion of the data is recorded to a region of the additional page having a relatively small selectivity compared to other regions of the additional page without recording on the other regions.

Abstract: An apparatus and a method for recording/reproducing data on a holographic storage medium using temperature information of the holographic storage medium. The apparatus includes: a light processing unit to record the data on the holographic storage medium or to reproduce the data from the holographic storage medium; and a control unit to control the light processing unit, such that the data is recorded on the holographic storage medium, using a recording wavelength determined according to a temperature of the holographic storage medium or an ambient temperature thereof.

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.