Abstract: The present invention makes it possible to reduce the size of an optical system for multiplex recording or reproduction of information utilizing holography. A pick-up of an optical information recording/reproducing apparatus generates information light by spatially modulating laser light emitted by a laser source device with a spatial light modulator depending on the information to be recorded and generates reference light for recording having a spatially modulated phase by spatially modulating the phase of laser beam emitted by the light source device with a phase-spatial light modulator. The information light and the reference light for recording are projected upon an optical information recording medium such that they converge in different positions, and information is recorded in the hologram layer in the form of an interference pattern as a result of interference between the information light reflected by a reflecting film and the reference light for recording.

Abstract: Optical information is stored in an optical information recording medium having an information recording layer utilizing holography with an optical information recording apparatus which includes security features. An input device is used to input individual information which is unique to an individual. An information light carries information to be recorded on the optical information recording medium. A phase modulation pattern is generated based on the individual information. A recording reference light is generated including a phase modulator for spatially modulating a phase of the reference light, for generating reference light for recording having a phase spatially modulated based on the phase modulation pattern information. A recording optical system illuminates the information recording layer on the same side with both the information light and the reference light.

Abstract: In a servo operation, position-controlling light, which is red light, is projected onto a recording medium so as to converge to a minimum diameter on a reflecting surface of the recording medium. In a recording operation, information light and recording-specific reference light, each of which is green light, are projected coaxially onto one side of an information recording layer of the recording medium so as to converge to a minimum diameter at an identical position located off the reflecting surface. Information is recorded in the information recording layer in the form of an interference pattern resulting from interference between the information light yet to impinge on the reflecting surface and the recording-specific reference light reflected by the reflecting surface and an interference pattern resulting from interference between the recording-specific reference light yet to impinge on the reflecting surface and the information light reflected by the reflecting surface.

Abstract: Recording of information by utilizing a holography to each information recording area while moving a record medium having information recording areas by means of a practical light source. For recording of information on an information recording area (7) of a record medium, an irradiated position (101) is moved so that the irradiated position (101) with information light and recording reference light may follow on information recording area (7) which moves for a predetermined period. Thus, one information recording area (7) keeps on being irradiated with information light and recording reference light, so that information is recorded on this information recording area (7) in interference patterns due to the interference of the information light with the recording reference light.

Abstract: Apparatus and method for recording and reproducing optical information using holography is designed to provide a small configuration and to improve the S/N ratio of reproduced information. During recording, a phase spatial light modulator generates information light spatially modulated in phase based on information to be recorded, and recording-specific reference light, that irradiate an information recording layer of an optical recording medium to record the information in the form of an interference pattern, resulting from interference between the information light and the recording-specific reference light. During reproduction, reproduction-specific reference light irradiates the information recording layer to generate reproduction light which is superimposed on the reproduction-specific reference light to generate composite light. The composite light is detected by a photodetector to reproduce the information.

Abstract: A method for recording information on a recording medium utilizing an interference pattern by interference between an information light modulated spatially with digital pattern information displayed on a spatial light modulator having multiple pixels and a reference light for recording. In order to provide a novel recording method capable of enhancing the recording density and the transfer rate furthermore, digital information to be recorded is represented by match/mismatch of the attributes of adjacent pixels in the spatial light modulator to produce digital pattern information.

Abstract: Optical information is stored in an optical information recording medium having an information recording layer utilizing holography with an optical information recording apparatus which includes security features. An input device is used to input individual information which is unique to an individual. An information light carries information to be recorded on the optical information recording medium. A phase modulation pattern is generated based on the individual information. A recording reference light is generated including a phase modulator for spatially modulating a phase of the reference light, for generating reference light for recording having a phase spatially modulated based on the phase modulation pattern information. A recording optical system illuminates the information recording layer on the same side with both the information light and the reference light.

Abstract: Holographic recording and reproducing using a compact configuration provides no reduction in the recording/reproducing capability. Information light and recording-specific reference light having a spatially modulated phase are generated and projected onto an optical recording medium coaxially that converge on a reflecting surface of a recording medium. P-polarized recording-specific reference light and S-polarized information light are each optically rotated by a two-way split optical rotation plate in directions different between respective half areas of the cross section of the beam thereof.

Abstract: The present invention makes it possible to reduce the size of an optical system for multiplex recording or reproduction of information utilizing holography. A pick-up (11) of an optical information recording/reproducing apparatus generates information light by spatially modulating laser light emitted by a light source device (25) with a spatial light modulator (18) depending on the information to be recorded and generates reference light for recording having a spatially modulated phase by spatially modulating the phase of laser beam emitted by the light source device (25) with a phase-spatial light modulator (17). The information light and the reference light for recording are projected upon an optical information recording medium (1) such that they converge in different positions, and information is recorded in the hologram layer (3) in the form of an interference pattern as a result of interference between the information light reflected by a reflecting film (5) and the reference light for recording.

Abstract: A spatial light modulator includes: a magnetic layer that is made of a magneto-optic material and includes a plurality of pixels in each of which a magnetization direction is independently set and each of which has a function of causing a rotation of a polarization direction of incident light depending on the magnetization direction by a magneto-optic effect; a plurality of first conductor layers and a plurality of second conductor layers arranged to intersect with each other at positions corresponding to the individual pixels, through which currents for generating magnetic fields to set the magnetization directions in the individual pixels are passed; and a plurality of dielectric layers for enhancing the function of the pixels. A polarization direction of light incident on the spatial light modulator is rotated depending on the magnetization direction of each pixel.

Abstract: An optical pick-up device that records and/or reproduces information on an optical information recording medium, through the use of holography, can prevent deterioration of recording and reproduction accuracy due to vibrations from exterior or fluctuations in the relative positional relationship with the recording medium. The optical pick-up device includes a pick-up body and a position adjusting device. The position adjusting device changes the position of the pick-up body in a direction perpendicular to a surface of the recording medium, in a direction parallel to the surface of the recording medium, and in such a direction as to change the inclination of the pick-up body with respect to the surface of the recording medium.

Abstract: An optical information-recording medium 1 is constituted by depositing a quarter-wave plate 4, a hologram-recording layer 3 and a reflection layer 5 on a transparent base plate 2 in this order. Reproducing reference light (P-polarized light) passes through the quarter-wave plate 4 to change into a circularly polarized light, and then the circularly polarized light enters the hologram-recording layer 3, so that the reproducing light (circular polarization) generated from the hologram-recording layer 3 passes through the quarter-wave plate 4 to change into a S-polarized light. On the other hand, stray light SL1 (P-polarized light) resulting from the process in which the reproducing light is reflected from the surface of the base plate or in the inside thereof has an vibration direction different from that in the stray light SL2 (P-polarized light) resulting from the process in which the reproducing reference light goes and returns in the inside of the optical information-recording medium 1.

Abstract: A spatial light modulator includes a device portion and a bias field applying coil disposed around the device portion. The device portion includes a magnetic layer and two types of conductor layers. The magnetic layer is made of a magneto-optic material and includes a plurality of pixels whose directions of magnetization are set independently of one another. Each of the pixels causes rotation of a direction of polarization of incident light depending on its direction of magnetization due to a magneto-optic effect. The conductor layers generate a magnetic field for setting the direction of magnetization of each of the pixels of the magnetic layer. Each of the pixels includes two regions which can take different states of magnetization. Information is produced by changing the states of magnetization in those regions.

Abstract: To record information, a recording/reproducing optical system in an optical head irradiates a recording medium with information light and reference light for recording so that two-dimensional image information is recorded on the recording medium by means of interference between the information light and the reference light for recording. To reproduce information, the recording/reproducing optical system irradiates the recording medium with reference light for reproduction, and collects and detects reproduction light occurring from the recording medium. An optical information recording/reproducing apparatus comprises a tilt detector and an image deviation correction circuit. The tilt detector detects a tilt of the recording medium with respect to a predetermined reference position.

Abstract: The present invention makes it possible to reduce the size of an optical system for multiplex recording or reproduction of information utilizing holography.

Abstract: A spatial light modulator includes: a magnetic layer that is made of a magneto-optic material and includes a plurality of pixels in each of which a magnetization direction is independently set and each of which has a function of causing a rotation of a polarization direction of incident light depending on the magnetization direction by a magneto-optic effect; a plurality of first conductor layers and a plurality of second conductor layers arranged to intersect with each other at positions corresponding to the individual pixels, through which currents for generating magnetic fields to set the magnetization directions in the individual pixels are passed; and a plurality of dielectric layers for enhancing the function of the pixels. A polarization direction of light incident on the spatial light modulator is rotated depending on the magnetization direction of each pixel.

Abstract: The present invention makes it possible to reduce the size of an optical system for multiplex recording or reproduction of information utilizing holography.