Abstract: Disclosed is an optical information recording and reproducing device capable of recording an interference fringe pattern as a hologram in an optical information recording medium, the interference fringe pattern being formed by a signal beam superimposed with signal information and a reference beam, and also capable of reproducing the signal information from the optical information recording medium, the device having a light source unit to emit light, a light splitting unit to split the light into the reference beam and the signal beam, a spatial light modulation unit to superimpose the signal information on the signal light, and a light detection unit to detect an image reproduced by the reference beam, wherein information about defects on the spatial light modulation unit is recorded in the optical information recording medium.

Abstract: A method implemented using a data recording system is disclosed. The method includes receiving a micro-holographic data storage medium comprising a micro-hologram track having a first cross-sectional area. The method further includes recording a data in the micro-hologram track to form a data track in the micro-hologram track having a second cross-sectional area smaller than the first cross-sectional area.

Abstract: There is disclosed an optical information recording/reproducing apparatus for optically recording and/or reproducing information in and from an optical recording medium. The apparatus has an oscillator light generator for generating oscillator light that is made to overlap and interfere with reproduced light from the optical recording medium, an oscillator light modulator for producing a given phase difference between the oscillator light and the reproduced light, a light detector for detecting interference light in which the oscillator light and the reproduced light overlap each other, a wavefront deviation detector for detecting an amount of wavefront deviation between the oscillator light and the reproduced light from an output from the light detector, and a compensation amount calculation unit for calculating a wavefront compensation amount from the amount of wavefront deviation. The phase difference produced by the oscillator light modulator is controlled based on the wavefront compensation amount.

Abstract: In an optical information recording device and optical information recording method for angularly multiplexing and recording data on pages on the same recording region on a hologram disk, data on each page is sequentially generated by sequentially dividing input data in predetermined units, the pages to be recorded on the same recording region are divided into page groups so that pages to be recorded adjacently by the angular multiplexing may not belong to the same group, each page group is individually subjected to inter-page coding processing for computing an error-correcting code and adding the computed error-correcting code, and data on the pages subjected to the inter-page coding processing is angularly multiplexed and recorded on the hologram disk.

Abstract: An apparatus and method for recording a micro-hologram are provided. The micro-hologram recording apparatus includes a first light source configured to emit a first light, the first light being coherent, a first optical system configured to divide the first light into a signal beam and a reference beam, and supply the signal beam and the reference beam to a location on a hologram recording medium, a second light source configured to emit a second light, the second light being incoherent and not interfering with the signal beam and the reference beam, and a second optical system configured to supply the second light to the same location as the signal beam and the reference beam on the hologram recording medium.

Abstract: A method and device for re-writing data on a holographic storage device is disclosed. First and second electro-optic modulators may phase shift the reference and data beams used to store data on the photorefractive crystal. When the reference beam is shifted 180° out of phase with respect to the data beam, the photorefractive crystal is erased.

Abstract: A holographic optical pickup device includes an image sensor that detects a diffracted beam generated from the region to be reproduced when irradiating an optical information recording medium with a reference beam, and sets the detected diffraction beam as a reproduction signal, and a photodetector that is different from the image sensor, which detects the diffracted beam generated from a recorded region in the recording medium when irradiating the recording medium with the reference beam. A light receiver of the photodetector is divided into a plurality of light receiving planes so as to generate the position error signal indicating the positional shifting of the region to be recorded/reproduced of the recording medium with respect to the objective lens from a differential signal of a plurality of signals derived from the respective light receiving planes.

Abstract: An optical pickup device includes a galvanometer mirror that changes an incident angle of a reference beam to an optical information recording medium, an image sensor that detects a diffracted beam from a region to be reproduced upon irradiation of the recording medium with the reference beam, and sets the detected diffracted beam to a reproduction signal, and a photodetector that detects the diffracted beam generated from a plurality of recorded regions upon irradiation of the recording medium with the reference beam. The photodetector includes a plurality of light receivers, and generates an angular error signal indicating positional shifting of the incident angle of the reference beam from a differential signal of a plurality of signals derived from the respective light receivers so as to control the angle of the galvanometer mirror.

Abstract: The present invention can properly correct spherical aberration. An optical disk device (10) displaces an objective lens (18) so that the objective lens is displaced to a reference lens position as a reference. The optical disk device (10) controls an information light condensing point changing mechanism (55) so as to adjust the focus (FM) of an information light beam (LM) to a recording depth (X) at which the information light beam (LM) is to be applied in a state of the objective lens (18) being placed at a reference lens position (SL). The optical disk device (10) controls a servo light condensing point changing mechanism (35) so as to adjust the focus (FS) of a servo light beam (LS) to a servo layer (104) in the state of the objective lens (18) being placed at the reference lens position (SL).

Abstract: In a method of recording and reading optical information in a recording medium using holography, a first recording operation is performed for recording optical information in a first recording region in an overlapping manner by allowing a reference beam and a signal beam with data loaded to interfere with each other in the first recording region, the reference beam being angularly multiplexed at predetermined intervals. Furthermore, a second recording operation is performed for recording optical information in a second recording region adjacent to the first recording region in an overlapping manner by allowing the reference beam and the signal beam to interfere with each other in the second recording region, the reference beam being angularly multiplexed between the predetermined intervals. Consequently, optical information can be recorded so as to easily detect and determine a selected reproducing beam, thus increasing the reading efficiency of the optical information.

Abstract: An information storage device includes an information recording medium, at least a single light source that emits laser light, an illuminating unit that illuminates substantially the same position of the information recording medium with two light rays generated from the laser light, in different directions, a light detecting unit that detects reflection light of the two light rays reflected from the information recording medium and outputs a detection signal, an operation unit that calculates position error information of the information recording medium based on the detection signal; and, a driving device that changes the position of the information recording medium based on the position error information.

Abstract: An information recording/reproducing device includes a radiation light source 1 such as a semiconductor laser, a spatial modulation element 6 that splits laser light 2 emitted from the radiation light source 1 into a large number of diffracted light rays, and an objective lens 7 that converges the large number of diffracted light rays onto different points. The laser light 2 emitted from the radiation light source 1 is split into a large number of diffracted light rays by the spatial modulation element 6, the large number of diffracted light rays are converged onto different points in the photosensitive layer 8b of the information recording medium 8 by the objective lens 7, and information is recorded in the photosensitive layer 8b of the information recording medium 8, using an assembly of these converging points. Accordingly, it is possible to provide an information recording device capable of realizing high-contrast recording in which stray light or diffraction has no influence during signal recording.

Abstract: An optical information recording medium includes a recording layer in which a track is formed, the track having recording marks linearly arranged thereon. Each recording mark has a dimension corresponding to a reference mark length, which serves as a reference, in a track direction along which the track extends, the dimension being smaller than dimensions of the recording mark in two directions perpendicular to the track direction.

Abstract: An optical recording medium is provided. The optical recording medium includes a multilayer including an N (N?5) number of interfaces capable of reflecting incident light.

Abstract: A method for servoing when reading out a recorded holographic disk or recording in a preformatted disk includes detecting a primary signal of a reflected primary beam from a target data track of a target data layer of the disk, wherein the primary beam of radiation has a first wavelength; comparing a power measurement of the primary signal with a threshold value of power; detecting a tracking signal of a reflected tracking beam from a reference layer of the disk in an event that the power measurement of the primary signal is below the threshold value, wherein the tracking beam of radiation has a second wavelength; generating a servo error signal based upon the primary signal or the tracking signal; actuating an optical sub-system based upon either of the primary servo error signal or the tracking servo error signal such that the primary beam focuses on the target data layer.

Abstract: A test element is disclosed for analyzing a human or animal body fluid sample. The test element includes a substrate carrying a test field with a reagent for effecting a detection reaction when exposed to the body fluid sample, and an optical data storage in which data regarding the test element, preferably calibration data, is stored. Accordingly, the data storage is a holographic data storage. A hologram reader also is disclosed for reading the data storage of such a test element. Moreover, a hologram label and a method for manufacturing a hologram label are disclosed, as is a medical product including a holographic data storage in which data regarding the product is stored.

Abstract: A method for recording information in form of a hologram. The method can generate a displacement signal by detecting a displacement of a holographic recording medium. The method can perform an exposure control operation that, if the sampling value of the displacement signal falls within an allowable displacement range, records the information item in the holographic recording medium, and if the sampling value of the displacement signal falls outside the allowable displacement range, blocks or reduces at least one of the information light and the reference light to a light intensity with which the information item is not recorded in the holographic recording medium.

Abstract: An optical data retrieval system configured to retrieve data from a data storage medium, including: a source of n path-entangled photons, where n is an integer of at least 2; a detector system configured to determine if n photons have been received; and a mechanism to direct photons from the source to the data storage medium and to the detector system.

Abstract: The presented invention relates to a method for reading data from a data page from an optical data storage medium, e.g. a holographic storage medium and to an apparatus for performing this method. At least one missing or wrong positioned sync mark on a read data page is identified and its corrected position is estimated. The estimated corrected sync mark position is used for further processing.

Abstract: Optical information recording medium comprises: a plurality of recording layers 14, each of which undergoes a change in refractive index by irradiation with recording beam; and an intermediate layer 15 provided between recording layers 14. The recording layer 14 contains polymer binder and dye dispersed in the polymer binder, and at least in proximity to an interface (far-side interface 18) between the intermediate layer 15 and a recording layer 14 disposed adjacent to incident side of the intermediate layer 15 from which the recording beam enters the intermediate layer, the intermediate layer 15 has refractive index different from that of the recording layer 14. Glass transition temperature of the polymer binder is lower than melting point and decomposition point of the dye, and refractive index of the polymer binder changes by receiving heat generated when the dye absorbs the recording beam, whereby information is recordable in the recording layer.

Abstract: In an optical information reproduction method for reproducing information using holography from a medium which records an interference pattern generated when overlapping a signal beam and a reference beam, the reference beam is radiated to the medium at a reference beam angle with a predetermined range for reproducing the information, a reproduction beam is generated by diffracting the reference beam with the interference pattern, the reproduction beam is detected by a photodetector; and the information is reproduced by processing a signal detected by the photodetector.

Abstract: A recording apparatus includes the following elements. A recording light source emits pulse laser light for recording. A first light source emits first CW laser light. An irradiation optical system irradiates an optical recording medium with the pulse laser light and the first CW laser light via an objective lens in the state in which the optical axis of the first CW laser light is tilted with respect to the optical axis of the pulse laser light. A reception optical system outputs, to a first light receiver, a returned light portion of the first CW laser light which has been reflected by a reflection surface formed on the optical recording medium and which has been input through the objective lens. A focus servo controller performs focus servo control for the objective lens on the basis of a first reception signal obtained by the first light receiver.

Abstract: A method for processing information is provided. The method includes directing a laser beam to a first track of a first layer of a holographic storage medium. The method also includes recording a base voltage based on a look-up table. The method includes directing the laser beam to a target track in the first layer, based on position information in tracks. Further, the method includes recording an offset voltage for the target track into the look-up table. Still further, the method includes directing the laser beam to a target layer based on position information in vertical wobbles. The method also includes recording an offset voltage for the target layer into the look-up table. Finally, the method includes determining a final voltage based on the look-up table and applying the final voltage to an actuator for moving the laser beam to a final target position in the holographic storage medium for recording and retrieval of information.

Abstract: The present invention relates to a reproduction device of a holographic memory capable of precisely reproducing multi-value phase information without being influenced by noise. This holographic memory reproduction device comprises: a hologram diffraction ray generation unit which irradiates a first reference ray to the holographic memory and generates a diffraction ray of the first hologram; a hologram generation unit which changes the phase of a second reference ray which may interfere with the diffraction ray of the first hologram and generates a second hologram from the diffraction ray of the first hologram and the second reference ray to which the phase has been changed; a detection unit which detects the intensity distribution of the second hologram; and a processing unit which demodulates the phase modulation signal or the space quadrature amplitude modulation signal on the basis of the intensity distribution.

Abstract: A recording device including a light irradiating and light receiving unit which, in regard to an optical recording medium, which has a reference surface and a recording layer which is formed at a depth position different from the reference surface, where a pit row where intervals of pit formable positions in one circumference is limited to a first interval is formed in the reference surface, and which has a plurality of pit row phases by intervals of the pit formable positions in a pit row formation direction being set in a position which is each deviated by a predetermined second interval in the pit row which are arranged in the radial direction, irradiates a first light as recording light with regard to the recording layer and a second light for obtaining reflected light from the reference surface and which receives reflected light of the second light from the reference surface.

Abstract: An optical disc device and a recording method is provided in which information can be additionally recorded on an optical disc, which has a servo layer and recording layers separately formed, by accurately correcting a relative angle between a light beam and the optical disc used in the previous recording without providing an area where recording is not performed while maintaining the stability of tracking servo. The above subject can be solved by studying with high accuracy the relative angle between the optical disc and the optical axis used in the previous recording by applying a radial tilt servo according to a signal from the recording layers with the tracking servo applied by the servo layer. Further, the additional recording can be performed stably by fixing the radial tilt at the previously studied angle when the recording is performed.

Abstract: Disclosed is an optical information reproducing apparatus that has a light path difference between two lights easily adjusted, has a high effect on the amplification of a signal, and detects an optical information signal of an interfering type. The optical information reproducing apparatus splits a luminous flux emitted from a laser source into a first luminous flux as a signal light and a second luminous flux as a reference light not collected on an optical information recoding medium, makes the signal light optically interfere with the reference light in a state in which the signal light and the reference light are different from each other in a phase relationship to thereby produce interfering lights, and detects the interfering lights.

Abstract: When ld0 denotes an initial optical path length that is a length of an optical path, along which the signal light travels, as converted using a refractive index in vacuum, lm0 denotes an initial optical path length that is a length of an optical path, along which the reference light travels, as converted using a refractive index in vacuum, ?l denotes a fluctuation width of a difference in optical path lengths between the signal light and the reference light as converted using a refractive index in vacuum, ?0 denotes a central oscillation wavelength of the wavelength-variable laser, and ?? denotes an oscillation wavelength variable range of the wavelength-variable laser, then an initial optical path difference |ld0?lm0| satisfies |ld0?lm0|>(?l/??)?0.

Abstract: Provided is an optical disc drive device which stably controls an actuator of an optical pickup, by individually controlling an optical spot when following the guide track and an optical spot when recording/reproducing information on/from each recording layer. An optical spot when following the guide track and an optical spot when recording/reproducing information on/from each recording layer are individually controlled. At this time, the optical spot exclusive for the track and the optical spot exclusive for the recording/reproducing are formed on an optical disc.

Abstract: A recording medium includes a photosensitive layer, a nonphotosensitive layer, and a recording layer formation region in which the photosensitive layer and the nonphotosensitive layer are laminated. The photosensitive layer includes a recording layer in which interference fringes formed in parallel with a recording medium surface are deleted or changed within a portion irradiated with focused light to record information or light reflected during irradiation of focused light is used to reproduce information.

Abstract: An optical information recording and reproducing apparatus includes an irradiation unit of a signal light beam and a reference light beam required for data recording, and a cure irradiation unit having at least one of a pre-cure irradiation that irradiates a predetermined light beam on to a desired position prior to irradiating the reference light bean and the signal light beam on to the desired position when information is recorded in the desired position on an optical information recording medium and a post-cure irradiation that irradiates a predetermined light beam on to the desired position so as to make the desired position non-recordable after the information is recorded in the desired position on the recording medium. The cure irradiation unit is disposed in one driving device in a freely movable manner in the driving device.

Abstract: An optical information recording/reproducing apparatus and an optical information recording/reproducing method that record information using holography, wherein the optical information recording/reproducing apparatus includes a signal generation unit that generates two-dimensional data by a two-dimensional encoding method in which a lower-limit value of a number of continuous ON/OFF pixels in an array in one direction of pixels in a two-dimensional spatial light modulator is K(K?2, K: natural number); and a pickup that records the two-dimensional data, generated by the signal generation unit, on a hologram disc.

Abstract: A method for 3D recording of data on a medium formed from a transparent photosensitive material including at least one dopant. The method includes a first step of calibrating and checking a pulsed light source including calibrating the number of pulses, the level of fluence of each pulse emitted and the rate of the pulses and a step of inscribing an area of the material. The fluence of each pulse emitted, the number of pulses and the rate of the pulses are suitable for irradiating the material in the area so as to form fluorescent clusters stabilized from the dopant while minimizing the modification of the refractive index and the absorption coefficient of the medium in a wavelength range from visible to near infrared.

Abstract: A 3D display device with controllable device for tracking visibility regions is disclosed, and includes a controllable device for tracking a visibility region, generated by way of superposition of light source images, in a observer plane of the display device. In preferred embodiments, the cladding of a waveguide comprises at least one material with optical properties of an anisotropic liquid, or at least two materials with optical properties of an isotropic liquid; a matrix arrangement of control electrodes defines multiple positions to be generated for local exit points in the cladding of the waveguide at which the total reflection is locally cancelled; and a system controller modifies positions of the output coupling points for superposing the output-coupled light through the lens array to the visibility region by displacing an output coupling point, or by switching off one output coupling point and switching on another one.

Abstract: The above-described problem can be solved by the following optical-information reproducing apparatus: An optical-information reproducing apparatus for reproducing a hologram storage medium into which an interference pattern is recorded as a hologram, the interference pattern being formed by causing a reference beam and a signal beam to interfere with each other, the optical-information reproducing apparatus, including an optical detector for detecting a reproduced beam, the reproduced beam being acquired by illuminating the recorded hologram with the reference beam, an optical element for generating a first reference beam and a second reference beam by branching the reference beam, a wavefront detector for detecting wavefront aberration of the reference beam by causing the first reference beam and the second reference beam to interfere with each other, and a wavefront compensator for compensating the wavefront of the reference beam, wherein the wavefront compensator is adjusted based on an output of the wavef

Abstract: The present disclosure relates generally to optical data storage media, and more specifically, to holographic storage media. In one embodiment, an optical storage medium includes a polymer matrix having one or more polymer chains. The optical storage medium also includes a reverse saturable absorption (RSA) sensitizer disposed within the polymer matrix that is configured to become excited upon exposure to light having an intensity above an intensity threshold and configured to transfer energy to a reactant. The optical storage medium also includes a diphenyl cyclopropene (DPCP)-derivative reactant disposed within the polymer matrix and capable of undergoing a modification upon receiving an energy transfer from the excited sensitizer that changes a refractive index of the optical medium.

Abstract: The invention relates generally to optical data storage media, and more specifically, to holographic storage media. In one embodiment, an optical storage medium composition includes a polymer matrix. Disposed within the polymer matrix is a reactant capable of undergoing a modification that alters the refractive index of the composition upon receiving an energy transfer from an excited sensitizer. A non-linear sensitizer is also disposed within the polymer matrix, and the sensitizer includes a metal-substituted subphthalocyanine (M-sub-PC) reverse saturable absorber configured to become excited upon exposure to light beyond an intensity threshold at approximately 405 nm and configured to transfer energy to the reactant.

Abstract: A method for adjusting at least one alignment control axis of a holographic data storage system or device to or towards a sufficiently optimal recovery position for recovery of a hologram based on a derived feedback error signal and/or a derived feed-forward signal. For the next hologram in the sequence, the derived feedback error signal estimates the direction and magnitude of misalignment of the at least one alignment control axis for one or more previously recovered holograms based on alignment-indicating data. The derived feed-forward signal estimates an optimal alignment value for the at least one alignment control axis for one or more holograms based on recording and recovery operating condition data for the holograms. An iterative alignment procedure may also be used to derive a feedback error signal for one hologram.

Abstract: An apparatus and method for processing optical information using a low density parity check code are suggested. An optical information recording method includes the steps of encoding data to record into a low density parity check code; representing the data, which is encoded into the low density parity check code, to a spatial light modulator in the unit of a data page; and modulating a recording beam into the data page representing the spatial light modulator to be recorded in the form of hologram in a recording medium. By blocking inexact probability information from being concentrated in the LDPC code block, by achieving exact probability information through effective allocation of a mark, and by improving average accuracy of the pixel, which corresponds to the LDPC code, failure rate of decoding can be minimized so that decoding performance can be improved.

Abstract: An optical information recording/reproducing apparatus includes a spatial light modulator that converts an irradiation beam emitted from a light source to a single information beam that carries information; an optical system that causes the single information beam to be collected on an optical-information recording medium including an information recording layer capable of recording the information as hologram by using interference fringes produced due to interference between the single information beam and a plurality of reference beams, and causes each of the reference beams to be irradiated to the optical-information recording medium from mutually different directions so as to intersect with the single information beam in the information recording layer; and a controller that controls to cause the light source to emit the irradiation beam and performs angular multiplexing recording of the information in the information recording layer while controlling to drive either one of the optical-information recordi

Abstract: A light irradiation device includes: a focus servo control unit including a light source, a spatial light modulating unit, and a light irradiating unit, for focus servo control so that the ideal focal position of light via an objective lens is such that distance between an ideal focal position and a hologram recording medium surface is smaller than distance from the surface to the lower layer side face of the recording layer, and the focal position of light via the objective lens is constant at the ideal focal position; an objective-lens/relay-lens distance adjusting unit to adjust distance between the objective lens and a relay lens close to the objective lens; a light reception unit to receive marker light; and a constant distance control unit to control the objective-lens/relay-lens distance adjusting unit based on error between the ideal position of the marker light, and the actual position of the marker light.

Abstract: A system and method for controlling tracking in a holographic data storage system, including: impinging a beam on a holographic data disc, wherein the beam is reflected from a micro-hologram disposed within the holographic data disc; detecting the reflected beam from the holographic data disc by a multi-element detector; and analyzing a pattern detected by multi-element detector to generate a tracking error signal.

Abstract: The present invention provides systems and methods for logically organizing data for storage and recovery on a data storage medium using a multi-level format. The present invention also provides systems and methods for protecting data stored on data storage medium so that the data may be recovered without errors.

Abstract: In an information storage device in which small partitions for storing information are three-dimensionally placed inside a solid, the invention aims at long-period storage, robustness, and rapid information reading. Accordingly, the stored three-dimensional information is divided into two-dimensional data for each layer, and two-dimensional inverse Fourier transform is previously applied for the two-dimensional data. The two-dimensional data is recorded in each layer in a Z direction inside a storage medium which is solid. When the information is reproduced, electromagnetic waves are irradiated to a storage area MA as gradually rotating the storage area MA around a z axis, and projection images of all layers during the rotation are obtained from response. By applying one-dimensional Fourier transform for a plurality of projection images obtained as described above, the recorded original three-dimensional information is rapidly reproduced.

Abstract: A method for generating a complex amplitude in-line hologram and an image recording device using said method makes it possible to realize high-speed processing and high-speed recording from a single off-axis hologram without limiting the spatial frequency band and without creating errors from interpolation. The complex amplitude in-line hologram is generated by performing the following in order: the acquisition of data for one off-axis hologram obtained by way of off-axis holography, and for an off-axis reference light used for obtaining the hologram; the setting of a reconstruction in-line reference light; a modulation process for performing spatial heterodyne modulation on the hologram on the basis of the phases of the reference lights; and a filtering process for performing spatial frequency filtering on the hologram modulated by the modulation process. Because spatial sampling is not performed, the limits on the viewing angle are relaxed.

Abstract: An apparatus for recording information in an optical-information recording media by holography includes a signal-light irradiation unit, a reference-light irradiation unit, a reference light angle adjustment unit, and a positioning unit for positioning irradiation positions of the signal light and the reference light. The optical-information recording media is divided into N (N?2) recording regions, M multiplexed information can be recorded in the respective recording regions by the reference light angle adjustment unit which changes the angle of the reference light at M angles (?1, ?2, . . . , and ?M) corresponding to a multiplexing number (M?2), management information for the M multiplexed information is multiplexed and recorded in the same recording region as a-th information (1?a?M) with a reference light angle ?a, and the management information on all the N recording regions are recorded at a common reference light angle.

Abstract: In one embodiment, a method is disclosed for recoding information in form of a hologram. The method can generate a displacement signal by detecting a displacement of a holographic recording medium. The method can perform an exposure control operation that, if the sampling value of the displacement signal falls within an allowable displacement range, records the information item in the holographic recording medium, and if the sampling value of the displacement signal falls outside the allowable displacement range, blocks or reduces at least one of the information light and the reference light to a light intensity with which the information item is not recorded in the holographic recording medium.

Abstract: The present invention achieves an optical recording and reproducing apparatus focusing two opposed beams of light at a same place in an optical recording medium to record a standing wave generated by interference of the two beams of light. In the apparatus, phase information is recorded in the optical recording medium by a phase modulating means for modulating phase of one of the two beams of light. The reproduction reference light generated from a light source is allowed to interfere with reproduced light generated by projecting one of the two beams of light onto the optical recording medium to generate three or more beams of interfering light having different interference phases are simultaneously generated. The three or more beams of interfering light are then detected, and the phase modulated by the phase modulating means is demodulated from an output of the detector.

Abstract: Provided are an optical information recording/reproducing apparatus and method capable of managing a wavelength of a light source when information is recorded/reproduced by utilizing holography, and limiting a wavelength of an interference fringe in a medium, and an optical information recording medium. For information recording/reproducing relative to an optical information recording medium by a pickup, a wavelength detector circuit detects a reference wavelength recorded in a storage area of the optical information recording medium, in accordance with the detected reference wavelength, a controller adjusts a wavelength of a light source of the pickup to have an optimum wavelength, and if a temperature detected with a temperature sensor indicates a predetermined change, readjusts the wavelength of the light source of the pickup to have an optimum wavelength.

Abstract: Techniques are provided for using a multi-stage actuator to actuate one or more optical components of an optical head. The multi-stage actuator includes a cross-layer displacement component which actuates an optical component to change the beam focus in a displacement range corresponding to the thickness of the data layers in a holographic disk, such that a beam is impinged on the target data layer. The multi-stage actuator also includes a intra-layer focusing component which actuates the optical component in a smaller range to focus the beam on the target data position. The cross-layer displacement component and the intra-layer focusing component may each include more than one actuator. In some embodiments, the focusing component also actuates the optical component in a tilting motion to compensate for movement or imperfections of the disk during a reading or recording process.