Abstract: A hologram apparatus which comprises a light generating unit that generates coherent reference light and coherent signal light modulated according to information to be recorded; an interference optical system that irradiates the signal light and the reference light toward the record medium to intersect therein, thus forming a diffraction grating inside the record medium by an optical interference pattern; and a photodetector that detects reproduced light. The hologram apparatus further comprises a second interference optical system that irradiates second signal light and second reference light to intersect inside the record medium, wherein the second signal light and the second reference light are placed in the plane of incidence including the signal light and the reference light of the interference optical system so as to be opposite to the signal light and the reference light with the record medium sandwiched in between; and a second photodetector that detects reproduced light.

Abstract: A holographic recording and reproducing apparatus comprises: a pickup for moving an objective lens that focuses a coherent light beam along a recording track on a holographic recording medium and for detecting reflected light from the recording track to perform focus- and tracking-servo control; a relative velocity determination unit for determining a relative velocity of a converging position of the objective lens with respect to the holographic recording medium; a driving unit for changing a relative position of the objective lens with respect to an optical path of the coherent light beam so as to make the relative velocity fall within a predetermined range at least during a predetermined period; and a control unit for performing recording or reproduction for a recording layer during the predetermined period. The holographic recording medium includes a plurality of markers used for positioning an optical interference pattern of the coherent light beam.

Abstract: A recording medium has a recording layer capable of be performed in recording or reproducing of information with light irradiation and carried with a substrate. The recording medium includes a guide layer having guide tracks each followed by a light beam spot focused from an objective lens through the recording layer, the guide tracks disposed at a first pitch. The recording medium includes a guide track transfer region provided on the guide layer and having at least one line of a track arranged in parallel between the guide tracks adjacent to each other in the extending direction of the guide track so as to be in a direction perpendicular to the guide track within a range shorter than that of the guide track.

Abstract: A hologram reproducing apparatus is provided that can be reduced in size. A hologram reproducing apparatus of the invention reproduces signal information from a recorded media having a domain of diffraction grating that is irradiated with a record light beam containing a coherent reference light component and a signal light component spatially modulated according to the signal information substantially on the same optical axis and is recorded an interference of the reference light component and the signal light component.

Abstract: A hologram recording apparatus (100) includes a record angle change device (19) capable of relatively changing the record angle of a hologram recording medium (200) relative to signal light (L3) and reference light (L2); and a control device (18). The control device sets a record angle for recording a specific angle record plane as a standard record angle among a plurality of angle record planes on the hologram recording medium. Furthermore, the control device controls the record angle change device so as to change and fix the record angle after then by a predetermined angle from the set standard record angle.

Abstract: A hologram record apparatus (100) includes a parameter set device (19), a move device (20), and a control device (18). The parameter set device (19) modifies parameters for multiple recordings such as a record angle and a focal depth in relation to at least one of signal light (L3) and reference light (L2) and can fix the parameters. The move device (20) relatively moves the focus position of the signal light and the reference light in the direction along the record surface of a hologram record medium. The control device (18) performs control so that the parameter for the last recording used for recording at the m-th focus position is used as the parameter for the first recording at the m+1-th focus position.

Abstract: A spatial light modulator, in which light modulation elements are arranged in a same plane. In the spatial light modulator, a plurality of the light modulation elements are arranged such that there are at least two periods of periodic structure corresponding to an arrangement of the light modulation elements in an arbitrary direction in the plane where the light modulation elements are arranged.

Abstract: A hologram device includes: a support section that keeps hold of, to be able to be attachable and removable, a hologram record carrier including a hologram recording layer stored therein with an optical interference pattern of a coherent signal light and a coherent reference light as a diffraction grating; a light source that generates the coherent reference light; a signal light generation section that is disposed on an optical axis, and generates the signal light by modulating the reference light in accordance with recording information; and an interference section that is disposed on the optical axis, and forms the diffraction grating being the optical interference pattern inside of the hologram recording layer by directing the signal light and the reference light toward the hologram recording layer.

Abstract: A holographic recording and reproducing apparatus comprises: a pickup for moving an objective lens that focuses a coherent light beam along a recording track on a holographic recording medium and for detecting reflected light from the recording track to perform focus- and tracking-servo control; a relative velocity determination unit for determining a relative velocity of a converging position of the objective lens with respect to the holographic recording medium; a driving unit for changing a relative position of the objective lens with respect to an optical path of the coherent light beam so as to make the relative velocity fall within a predetermined range at least during a predetermined period; and a control unit for performing recording or reproduction for a recording layer during the predetermined period. The holographic recording medium includes a plurality of markers used for positioning an optical interference pattern of the coherent light beam.

Abstract: An example recording apparatus includes a pulse oscillation laser, a half mirror for splitting the pulse oscillation light of the laser into a signal light and a reference light, an optical shutter disposed in the optical path of the signal light, a beam expander for converting the signal light into a light beam of a predetermined diameter, a spatial modulator for modulating the recording data into two-dimensional image information, a Fourier Transform lens for introducing the signal light modulated by the spatial modulator onto a recording medium, mirrors for introducing the reference light onto the recording medium with a predetermined angle, a system control unit, a laser driver, a system controller, a recording medium drive mechanism, a modulator driver, a data input unit, and a data processing unit.

Abstract: A hologram record apparatus (100) includes a spatial light modulator (15) and a control device (18). The spatial light modulator (15) is arranged on an optical path of signal light (L1) and divided into a plurality of cell blocks (151) arranged in a matrix. Each of the cell blocks (151) is further divided into a plurality of cells (152) arranged in a matrix. The spatial light modulator (15) can perform modulation on the cell basis. The control device (18) controls the spatial light modulator so as to modulate the signal light according to a plurality of record information sets to be recorded on a hologram record medium (200). Pluralities of modulation units (153) existing in the same cell block are not made into identical patterns. Since a plurality of cell blocks having a large pitch as compared to the pixel pitch are simultaneously or successively turned on/off, it is possible to reduce the distance between the zeroth-order light and the higher-order light.

Abstract: A hologram recording medium is a hologram recording medium which is irradiated with light for recording information therein or reproducing information therefrom. The hologram recording medium has a recording layer made of a photo-sensitive material capable of preserving an optical interference pattern, a reflective layer disposed on one side of the recording layer opposite to the side on which an light beam impinges, and a quarter wavelength plate interposed between the recording layer and the reflective layer.

Abstract: A recording mark train is formed in an optical recording medium including a noble metal oxide layer by decomposing a noble metal oxide and deforming the noble metal oxide layer. Noble metal particles are irreversibly deposit in the noble metal oxide layer formed with the recording mark train and a laser beam for reproducing data is irradiated onto the thus deposited noble metal particles, thereby reading the recording mark train. The recording mark train includes at least one recording mark having a length shorter than 0.37?/NA wherein ? is the wavelength of the laser beam and NA is an optical system for irradiating the laser beam.

Abstract: A compatible hologram system has a supporting part for loadably supporting a recording medium made of a photosensitive material, a signal generating part for allowing a coherent beam modulated in response to predetermined data to enter the recording medium and providing a three-dimensional light interference pattern therewithin to produce a diffraction grating, and a data processing part for detecting reproduced data by diffracted light from the diffraction grating and demodulating the data to the predetermined data. The recording medium has a reference data area in which a reference diffraction grating corresponding to a three-dimensional light interference pattern of a coherent light beam modulated in response to reference data has been stored in advance, a sector data area in which sector data is recorded, and a user data area in which user data is recorded.

Abstract: A hologram recording and reproducing system having compatibility has: a supporting unit for freely attachably supporting a recording medium including a photosensitive material; a signal light-generating unit for projecting a coherent light beam modulated according to a predetermined data into a recording medium and generating a diffraction grating by providing a three-dimensional light interference pattern in the recording medium; a detector unit for detecting and photoelectrically converting a diffracted light from the diffraction grating; and a demodulating unit for demodulating a predetermined data from an output from the detector unit. The detector unit has an intermediate data-generating unit for generating an intermediate data, and the demodulating unit has a conversion table in which the intermediate data and the predetermined data are uniquely associated, and demodulates the predetermined data by performing a computation based on a correlation in the conversion table.

Abstract: A hologram recording apparatus (100) includes a record angle change device (19) capable of relatively changing the record angle of a hologram recording medium (200) relative to signal light (L3) and reference light (L2); and a control device (18). The control device sets a record angle for recording a specific angle record plane as a standard record angle among a plurality of angle record planes on the hologram recording medium. Furthermore, the control device controls the record angle change device so as to change and fix the record angle after then by a predetermined angle from the set standard record angle.

Abstract: A hologram apparatus includes a light beam interfering section for allowing reference and signal light beams to interfere to form a hologram recording region; a reproducing section for allowing the reference light beam to be incident on the recording region and generating a reproduced light; an image sensor for detecting a hologram-reproduced image; a distortion determining section for detecting the distortion-detecting data from the hologram-reproduced image to determine a distortion of the hologram-reproduced image; a distortion corrector for correcting a distortion of the hologram-reproduced image; and a controller for correcting the distortion in accordance with a determined distortion.

Abstract: A spatial light modulator, in which light modulation elements are arranged in a same plane. In the spatial light modulator, a plurality of the light modulation elements are arranged such that there are at least two periods of periodic structure corresponding to an arrangement of the light modulation elements in an arbitrary direction in the plane where the light modulation elements are arranged.

Abstract: A recording apparatus includes a pulse oscillation laser (11), a half mirror (12) for splitting the pulse oscillation light of the laser into a signal light (2) and a reference light (3), an optical shutter (13) disposed in the optical path of the signal light, a beam expander (14) for converting the signal light into a light beam of a predetermined diameter, a spatial modulator (15) for modulating the recording data into two-dimensional image information, a Fourier Transform lens (16) for introducing the signal light modulated by the spatial modulator onto a recording medium (1), mirrors (17, 18) for introducing the reference light onto the recording medium with a predetermined angle, a system control unit (21), a laser driver (22), a system controller (23), a recording medium drive mechanism (24), a modulator driver (25), a data input unit (26a), and a data processing unit (27).

Abstract: A holographic recording and reproducing apparatus comprises: a pickup for moving an objective lens that focuses a coherent light beam along a recording track on a holographic recording medium and for detecting reflected light from the recording track to perform focus- and tracking-servo control; a relative velocity determination unit for determining a relative velocity of a converging position of the objective lens with respect to the holographic recording medium; a driving unit for changing a relative position of the objective lens with respect to an optical path of the coherent light beam so as to make the relative velocity fall within a predetermined range at least during a predetermined period; and a control unit for performing recording or reproduction for a recording layer during the predetermined period. The holographic recording medium includes a plurality of markers used for positioning an optical interference pattern of the coherent light beam.