Abstract: A hologram recording and reproducing device controls an optical beam output from an external cavity semiconductor laser to improve a diffraction efficiency. The hologram recording and reproducing device includes an external cavity laser, a photodiode, a laser drive circuit and a laser diode controller. The external cavity laser has a laser diode adapted to emit an optical beam that is used to generate data light and reference light with which a hologram recording medium is irradiated. The photodiode detects the amount of the optical beam output from the external cavity laser. The laser drive circuit supplies a current to the external cavity laser. The laser diode controller controls the laser drive circuit to ensure that a value obtained by integrating the detected intensity of the optical beam with respect to time over a predetermined period is equal to predetermined recording energy.

Abstract: A holographic storage medium, and a method and an apparatus for recording/reproducing data on/from the holographic storage medium, the method recording data on the holographic storage medium as holograms recorded in datapages, and dividing one of the datapages into a plurality of regions; and recording the data at various sampling rates in the respective regions.

Abstract: The present invention relates to an apparatus for writing to optical storage media capable of performing pre-exposure and/or curing of a photo-sensitive material for optical data storage, in particular for holographic data storage. The apparatus has a first light source for emitting a first light beam, a second light source for emitting a second light beam, and a spatial light modulator, which is switchable between at least two states for spatially modulating at least a part of the first light beam, and which is arranged such that in a first state it directs the first light beam towards an optical storage medium, and that in a second state it directs the second light beam towards the optical storage medium.

Abstract: A hologram recording/reproducing device includes a recording/reproducing optical unit performing recording and reproducing operations on a hologram recording/reproducing medium. The optical unit includes a laser light source emitting laser light; a spatial-light modulator generating signal light and reference light from the laser light, the signal light and reference light having a common light path; a phase mask disposed near the modulator or in a conjugate plane of the modulator and transmitting at least the reference light; and an objective lens including a first lens portion and a second lens portion. The first lens portion is disposed at an inner peripheral portion of the objective lens and serves as a Fourier transformation lens focusing the signal light to a predetermined point.

Abstract: The present techniques provide methods and systems reading a data bit of interest on an optical data disc with a reduced error rate. The data bit estimation may be improved by reducing deterministic noise resulting from an optical reader system and/or the optical data disc. The reader may adjust the position of a detector to detect light scattered from the disc based on parameters of known noise sources. In one embodiment, the detector may be moved vertically in relation to the data bit of interest on the optical disc. In another embodiment, more than one detector may be used to detect light scattered from a data bit of interest. In embodiments, the positioning of the detector(s) may be based on system or disc parameters, and the detected scatterings may provide a data reading, improved for an optical return from a present micro-hologram.

Abstract: A recording signal beam and a recording reference beam are irradiated onto a first surface of a holographic recording medium to write an information as an interference pattern therein. Next, a reflective layer is provided on a second surface opposite to the first surface of the holographic recording medium such that the reflective layer is adhered with the second surface, and a reproducing reference beam is irradiated onto the first surface of the holographic recording medium so as to read a signal beam which is reflected at the reflective layer and reproduced from the holographic recording medium.

Abstract: A hologram media reading apparatus including a reference light source, a stop with gray level aperture, and an optical sensor is provided. The reference light source is disposed on one side of a hologram medium, and capable of emitting a reference light beam. The reference light beam is transmitted to the hologram medium. The stop with gray level aperture and the reference light source are disposed on the same side or opposite sides of the hologram medium. The stop with gray level aperture has a light transmissive region, an opaque region, and a transmittance gradually varying region. The opaque region surrounds the light transmissive region. The transmittance gradually varying region surrounds the light transmissive region. A part of the reference beam from the hologram medium passes through the stop with gray level aperture and is transmitted to the optical sensor.

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: There is provided an optical reproducing device including: a reproducing component that includes a light source, a spatial light modulator, and a light guiding component, with the reproducing component irradiating, with reference light that has been generated by the spatial light modulator as reading light, a Fourier transform hologram; a splitting component disposed on a signal light exiting side of the reproducing component and that splits, into two light waves, the signal light; a first image acquiring component that detects the one split light wave to acquire a first reproduced image; a second image acquiring component that detects light where a direct current component has been removed from the other split light wave to acquire a second reproduced image; and a decoding component that uses the first reproduced image and the second reproduced image to decode data that the signal light has.

Abstract: There is provided an optical reproduction device that reproduces a hologram that is recorded on an optical recording medium by interference between a signal light and a reference light coaxial to the signal light. The device has: a coherent light source; a light distribution unit distributing light from the light source, to a signal light optical path and a reference light optical path; a spatial light modulator that includes a signal light region and a reference light region, a spatial light modulator, a first irradiation optical system spatially separating light distributed to the reference light optical path and light distributed to the signal light optical path, making optical axes of both lights coincide, and irradiating the both lights onto the spatial light modulator; and a second irradiation optical system irradiating reference light onto the optical recording medium as reading light, and reproducing the hologram.

Abstract: A photodetector integrated circuit (PDIC) capable of being used with at least two different types of optical discs includes a photodetector (PD) array and a switch matrix. The PD array includes a center channel PD and a side channel PD electrically isolated from the center channel PD. The switch matrix, which includes a plurality of inputs and a plurality of outputs, can be selectively configured in a plurality of different switch configurations. The side channel PD includes a plurality of electrically isolated PD sections. Each electrically isolated PD section of the side channel PD is adapted to detect light and provide an electrical output signal, indicative of the light detected by the PD section, to a different one of the inputs of the switch matrix.

Abstract: A multiple wavelength-adaptive optical pickup according to the present invention enables to obtain stable signals by suppressing displacement of optical intensity distribution at a light receiving section. When an incident angle of a central beam of a zero-dimensional beam of a beam reflected at an optical disc into a half mirror is taken as ?, if variation in transmittance of the mirror become a maximum with respect to change in the incident angle from ? to a plus side in any one of the wavelengths corresponding to the respective optical discs, a ?1 dimensional beam generated on the minus side with respect to the zero-dimensional beam is received by the light receiving section, and if the variation in the transmittance of the mirror become the maximum with respect to change in the incident angle from ? to the minus side, a +1 dimensional beam generated on the plus side with respect to the zero-dimensional beam is received by the light receiving section.

Abstract: An optical disc device that irradiates a light beam on an optical disc having a recording layer in which information is recorded and a positioning layer in which tracks for specifying a recording position of the information in the recording layer are provided includes an information recording unit that irradiates a light beam for information on a target position in the recording layer to record the information by shifting a position in an optical axis direction of the light beam for information, a terminal-end recognizing unit that recognizes, when new information is recorded in a recording layer having a recorded area in which information is already recorded, a terminal end of the recorded area, and a target-position setting unit that sets the target position to separate the terminal end of the recorded area and a start end of a recording planned area in which information is recorded anew.

Abstract: The invention concerns the field of holographic storage units. More particularly, the invention concerns the field of holographic storage units used for bit-by-bit storage of information. It concerns a method for reading data recorded in a holographic material in the form of a hologram obtained by interference of two beams of substantially the same wavelength, and using at least one reflecting layer. The invention is characterized in that it includes the following steps: emitting a light comprising at least said wavelength at said holographic material comprising said hologram; performing a homodyne detection between the signal resulting from the first light diffracted by said hologram and at least one signal selected between the reflected signal and the signal transmitted by said at least one reflecting layer.

Abstract: A recording method which optically records two-dimensional data including a positioning mark and data area in a recording medium. In this method, the state of the positioning mark is changed from a first state to at least one second state different from the first state every given number of recording times of such two-dimensional data.

Abstract: A recording apparatus includes a first light source irradiating first laser light, a second light source irradiating second laser light, an optical spatial modulating unit applying information to the first laser light, and an objective lens collecting the first laser light and the second laser light at different positions on the same optical axis. A hologram recording operation uses a first optical path and a second optical path. The information light is conducted to the objective lens along the first optical path. The reference light is conducted to the objective lens along the second optical path. At the same time, an address/servo control operation is carried out by employing a third optical path along which the second laser light is conducted to the objective lens. The DVD recording operation uses the second optical path. The CD recording operation uses the third optical path.

Abstract: A holographic recoding medium is provided, having holographic pages. Each page has reference mark (RM) placement areas at fixed locations for placing RM patterns. The reference marks are used to calibrate data images of data areas each of which is enclosed by at least three RM regions. Hidden information of the medium is stored by an specific encoded pattern based on existence, types and arrangements of the RM marks.

Abstract: An optical disc apparatus that records recording marks in a plurality of mark layers by irradiating predetermined light onto a disc-like volume type recording medium on the basis of information to be recorded is disclosed. The apparatus includes: a first focus position adjusting means for adjusting the position of a focus on which a first light beam focuses within the volume type recording medium, in the direction of an optical axis of the first light beam; a second focus position adjusting means for adjusting the position of a focus on which a second light beam focuses within the volume type recording medium, in the direction of an optical axis of the second light beam; a focus control means for controlling the first focus position adjusting means and the second focus position adjusting means; and a recording control means for forming the recording marks at the positions of respective focuses.

Abstract: An embodiment of the present invention includes rotating an integrated disc formed by temporarily fixing an initialization reference plate to an uninitialized optical disc that is an optical disc to be irradiated with a light beam of light having a predetermined or higher intensity to record information as a recording mark. The initialization reference plate has a reference part that reflects at least a part of a servo light beam of servo light intended for servo control. The reference part contains information that indicates the position of a track of the optical disc for the recording mark to be formed on, in the form of a track of pit-and-projection pattern.

Abstract: A hologram recording apparatus (300) is provided with: a recording device (100) for recording record information into a hologram recording medium (1); a measuring device (325) for measuring a time elapsed from when the recording of the record information is stopped to when the recording of the record information is restarted; a first controlling device (354) for controlling the recording device to multiplex-record the record information, if the measured elapsed time is shorter than a time length in which the record information can be multiplex-recorded; and a second controlling device (354) for controlling the recording device not to multiplex-record the record information, if the measured elapsed time is longer than the time length in which the record information can be multiplex-recorded.

Abstract: An optical information recording device includes: a section that acquires recording information that should be recorded on an optical information recording medium on which information are recorded by forming a recording mark at a position where an optical beam is focused on and from which the information are reproduced based on the reflectance of the recording mark; a section including at least one or more one-surface beam emission sections that emit a recording beam according to part of the recording information to one surface of the recording medium and focus the beam on a target position to form the recording mark; and an section including at least one or more other-surface beam emission sections that emit an recording beam according to the rest of the recording information to the other surface of the recording medium and focus the beam on a target position to form the recording mark.

Abstract: An optical disc apparatus and a focus position control method can highly accurately record recording marks representing information on or reproduce such recording marks from an optical disc. A blue light beam is irradiated onto the target depth to be irradiated by driving an objective lens to focus a red light beam in a reflection/transmission film formed in the optical disc and displacing a movable lens, which is a focus moving section, of a relay lens. A blue light reflection region is formed as part of the reflection/transmission film and the position of the blue light reflection region where the red light focus and the blue light focus are aligned is defined as reference position. The movable lens is displaced by an arbitrarily selected quantity from the reference position according to the target depth.

Abstract: A micro-holographic data storage system and method. Micro-holograms are written to a data storage medium with two counter-propagating beams via objective recording lenses which have a first numerical aperture (NA) to make the micro-holograms larger. Alternatively, elongated micro-holograms can be produced using counter-propagating beams with different focus points. The micro-holograms are retrieved from the data storage medium using a single beam via an objective reading lens which has a second NA that is higher than the first NA. The data storage medium has a substrate with a plurality of tracks separated by a track pitch. The plurality of micro-holograms are each contained in each of the plurality of tracks, wherein, at least one of the plurality of micro-holograms has a width which is nearly equal to a width of the track pitch.

Abstract: Provided are a method for detecting a pattern of an over-sampling image and an optical information processing apparatus and method using the same. A method for detecting a pattern from an image of an over-sampled datapage includes: over-sampling the datapage to detect a detection image of the datapage; comparing the detection image and a reference image of over-sampling for the pattern by a covariance; and calculating a pixel of the pattern over-sampled by values of the reference image and the detection image compared by the covariance. Accordingly, data with a specific pattern such as a mark can be detected from an image of an over-sampled datapage, thereby making it possible to increase the data reproduction accuracy, thus making it possible to greatly increase the reliability of reproduced optical data.

Abstract: An optical head device includes a light source configured to emit a light beam, a light collecting optical system configured to converge the light beam onto an information recording medium, a hologram element configured to diffract the light beam reflected from the information recording medium, and a photodetector having a plurality of detection regions configured to receive the light beam diffracted by the hologram element. The hologram element has a plurality of diffraction regions separated from each other by a straight line extending in a track direction of the information recording medium. At least one of the plurality of diffraction regions has a pattern which introduces coma aberration in the track direction to the diffracted light.

Abstract: A holographic storage medium, and a method and an apparatus for recording/reproducing data on/from the holographic storage medium. The method including: dividing a datapage into a plurality of regions; modulating the data into codewords having different on-pixel rates; and arranging the codewords in the plurality of regions, based on the different on-pixel rates.

Abstract: This invention relates to holographic film for recording multicolor volume holograms, especially full color volume reflection holograms, and to manufacturing techniques for such film, and to corresponding methods of recording multicolor and full-color volume, in particular volume reflection holograms. We describe a holographic film for recording a multicolor volume hologram, the film comprising: a carrier; a first photosensitive recording layer sensitive to one or both of red and green laser light; and a second photosensitive recording layer sensitive to blue laser light. Both the first and second photosensitive recording layers comprise silver halide and have a grain size of less than 30 nm, and at least one of the photosensitive recording layers has a thickness of greater than 3 ?m and less than 5 ?m.

Abstract: An optical information recording and reproducing apparatus for recording information on a recording medium by forming interference fringes generated by interference between an information beam and a reference beam on the recording medium and for reproducing the information by irradiating, with the reference beam, the recording medium, in which the interference fringes are formed. The apparatus includes a spatial light modulator for spatially modulating at least a portion of a light beam emitted from a light source into the information beam. A light sensing device reads the information beam extracted from the recording medium by the reference beam irradiated on the recording medium.

Abstract: In order, in the case of a holographic system, in particular for holographic data storage, comprising a radiation source for emission of a radiation an objective lens, a signal evaluation means, a detector and an optical data storage medium, the optical data storage medium having at least one data carrier layer and at least one beam-reflecting layer, to provide a solution which forms a small, compact and robust unit, in the case of which the signal beam crosses the reference beam only once, which avoids the use of optical beam splitters and requires a minimal alignment outlay, it is proposed that the objective lens has a plurality of sections, at least two beams that run parallel passing through the objective lens in a respective section and the at least two beams focusing at respectively separate locations on a plane in the optical data storage medium, at least one beam reflected in the optical data storage medium passing through the objective lens again in a respective further section.

Abstract: An optical pickup compatible with different types of optically recorded media and an optical recording and/or reproducing system employing the compatible optical pickup, the compatible optical pickup including: a short wavelength light source emitting a short wavelength light; a low-density optical system emitting a long wavelength light; an objective lens focusing lights incident from the long wavelength light source and the low-density optical system onto an information storage medium; a single photodetector (PD) receiving the short and long wavelength lights reflected from the information storage medium; a detection lens focusing the short and long wavelength lights reflected from the information storage medium as a light spot onto the single PD; a first collimating lens positioned on an optical path of a light reflected, wherein the optical path is positioned between the objective lens and the single PD; and a driving unit adjusting a position of the first collimating lens.

Abstract: An improved holographic data storage disc is provided. The holographic data storage disc includes multiple multimedia content, wherein at least one of the multimedia is locked via one or more cryptographic keys.

Abstract: An optical disc drive for recording and/or reading information on or from an optical disc is disclosed. The optical disc drive includes: a position controller which controls the position of the objective lens based on the position-controlling light beam reflected by the reflective surface by condensing the position-controlling light beam by the objective lens such that the position-controlling light beam is brought to a focus at a target guide position on the reflective surface corresponding to the target recording position; a tilt angle detector which detects tilt angle of the optical disc relative to optical axis of the position-controlling light beam; and a focal position corrector which makes a correction such that a focal position obtained when the information light beam is condensed by the objective lens is aligned to the target recording position according to the tilt angle.

Abstract: A method for holographic information storage and retrieval is disclosed. The method supplies a holographic data storage system comprising a light source and a holographic data storage medium and provides information to the holographic data storage system. The method generates a reference beam using the light source, forms a data beam comprising a data image and an orientation image, wherein the data image comprises all or a portion of the information. The method then generates a hologram using the data beam and the write reference beam, and encodes the hologram in the holographic data storage medium to form an encoded holographic data storage medium.

Abstract: An information recording apparatus for recording information on a multi-layered optical information recording medium having a recording material, which changes quality according to light intensity of an irradiated light, and having an altered layer in which the recording material is already altered and a non-altered layer in which the recording material is not yet altered alternately existing in plurals is provided. The information recording apparatus includes a light source for emitting a recording light having coherency; a light path branching unit for branching a light path of the light into a first light path and a second light path; focal position control units for controlling focal positions of the light in the first and the second light path; and objective lenses for collecting the lights in the first and the second light path on the recording medium.

Abstract: A method of recording content comprising the steps of: providing a content storage medium comprising a pre-recorded grating or hologram; and illuminating a pre-recorded grating or hologram with a single recording beam to record content in the grating or hologram. The recording beam may increase the diffraction efficiency of the pre-recorded grating or hologram. Alternatively, the recording beam may form a new grating or hologram in close proximity to a pre-recorded grating or hologram.

Abstract: An optical head apparatus including a holographic optical device which diffracts a light beam and includes a first diffraction region and a second diffraction region facing each other across a region dividing line passing through an optical axis of a light-collection optical system and extending in a radial direction of an optical disc, the first diffraction region having a grating pattern for generating diffracted light having a first wavefront and entering a first photoreception region and a second photoreception region, the second diffraction region having a grating pattern for generating diffracted light having a second wavefront and entering a third photoreception region and a fourth photoreception region, the first and second wavefronts having first and second coma aberrations in the radial direction of the optical disc, respectively, and the first and second coma aberrations having axes located off the optical axis.

Abstract: The present invention aims to provide an optical recording method etc. that provides higher efficiency of recording and reproducing and is uninfluenced by the mismatch of optical axes of plural laser lights induced from accident errors of optical recording and optical reproducing apparatuses when carrying out recording or reproducing, or focus control etc. by use of a laser light, high multiple-recording can be carried out, and layer construction of the recording medium itself is simple. For the purpose, an optical recording method etc.

Abstract: A recording/reproducing method and recording/reproducing apparatus, which use an information storage medium by adaptively preparing a standard for distinguishing bit 0 from bit 1 of data read from a holographic information storage medium, and a holographic information storage medium. At least one record unit data is recorded on the holographic information storage medium. The record unit data is divided into at least one sub area, and information about the distribution of bits included in the sub area is arranged in the sub area.

Abstract: An information recording/reproducing device irradiates a signal light beam containing arbitrary two-dimensional information and a reference beam emitted from the same light source as the signal light beam to an arbitrary region of a hologram recording medium to record a first hologram. After the first hologram is recorded, the device changes the incident angle of the signal light beam with respect to the hologram recording medium and multiplex-records a second hologram, which is different from the first hologram, in the same region as the region in which the first hologram is recorded by irradiating a signal light beam whose incident angle has been changed and a reference beam substantially the same as the reference beam used when recording the first hologram while the device obtains at least a part of a diffracted beam from the first hologram simultaneously.

Abstract: A beam applying method includes the steps of: rotationally driving an optical recording medium, in which a signal is recorded and reproduced by applying a beam thereto and which has a recording layer on which the signal is recorded, a polarization element formed below the recording layer, and a reflecting film formed below the polarization element; and applying a beam to the rotating optical recording medium through a half-wavelength plate that is rotationally driven with the rotation of the optical recording medium.

Abstract: A two-dimensional demodulation method for reproducing a data page by means of decision feedback Viterbi detection processing from a recording medium on which a data page has been recorded as a set of a plurality of two-dimensional modulation pattern symbols each of which comprises a plurality of pixels, and which have been modulated two-dimensionally, the method comprising: a step of determining a value of pixel deviation in a reproduction image obtained by receiving light from the recording medium on an image sensor; a step of splitting an output signal of the image sensor which indicates the reproduction image of the light received from the recording medium into signal symbol data by division into blocks in accordance with the two-dimensional modulation pattern symbols; and a step of carrying out decision feedback Viterbi detection for each signal symbol data in accordance with the pixel deviation value.

Abstract: A two-dimensional digital data acquisition element includes: a pixel area having a plurality of pixels arranged in a matrix form, each of the pixels having a photoelectric conversion element to convert the reproduced light from the optical information recording medium to an electric signal; selection circuits which select the pixel; a readout circuit which reads out an electric signal of a pixel selected by the selection circuits; and a 1-bit AD converter which converts an output of the readout circuit to 1-bit digital data. A pitch ratio N between a pitch P1 of the unit data areas in the two-dimensional digital image information and a pitch P2 of the pixels in the pixel area defined as N=P1/P2 satisfies a relation A·n2/(An+1)<N<A·n2/(An?1) where A is the number of digital data in one-dimensional direction of one byte of the two-dimensional digital data and n is a natural number of at least 2.

Abstract: To provide a hologram information recording medium and a hologram information recording/reproducing device capable of accurately reproducing data multiplexed on the recording medium irrespective of the influence of the external environment and so forth. In one recording area 31 of a recording medium 3, a plurality of the same information groups are recorded in substantially the same area with varied multi-parameters, in consideration of the expansion and the contraction of the recording medium 3. That is, a plurality of data groups A to D are recorded in the one recording area 31 of the recording medium 3, with a laser wavelength ? varied. Specifically, the data groups A to D are recorded in one recording area as three groups: a data group G1 including data A1, data B1, data C1, and data D1; a data group G2 including data A2, data B2, data C2, and data D2; and a data group G3 including data A3, data B3, data C3, and data D3.

Abstract: A recording medium, a recording/reproducing method of the same and an apparatus therefor, by which data of high volume can be recorded/reproduced. The present invention includes the steps of inserting a reference pattern including a multiple divided areas in a data image and recording the data image in the recording medium, wherein the multiple divided areas are in a relation of inversion and/or rotation and/or symmetrization.

Abstract: A hologram recording apparatus (300) records record information into a hologram recording medium (100) on which a hologram recording layer (11) and a position information recording layer (13). The hologram recording apparatus is provided with: a first recording device (101) for recording the record information into the hologram recording layer; and a second recording device (121) for setting an area portion of the position information recording layer in a recorded state, the area portion of the position information recording layer corresponding to an area portion of the hologram recording layer in which the record information is recorded.

Abstract: An apparatus for recording/reproducing data using holography technology and a method of reproducing data using the same are disclosed. The recording/reproducing apparatus includes an optical path adjuster which adjusts the path of light emitted from a light source and irradiates the light to a predetermined position of a recording medium, a light reflecting unit which reflects the light transmitting through the recording medium to the predetermined position of the recording medium, an image sensor which receives the reflected light and reproduces data included in the reflected light, and a light receiving unit receiving light, which is not transmitted through the recording medium and is diffracted from the recording medium, and generating a monitoring signal. Accordingly, it is possible to provide a simple optical system suitable for the recording/reproducing apparatus using the holography technology and an efficient method of reproducing data using the same.

Abstract: An optical signal recording medium includes at least one signal recoding plane in which an optical signal is to be recorded, and a control information region which is a portion other than the signal recoding plane, and in which a diffraction grating is disposed.

Abstract: A method for to restore quantization data to binary data in a system for recording and/or reproducing the binary data includes selecting a selection region predicted to include an alignment mark from the quantization data, determining a location of the alignment mark within the selection region; and converting the quantization data to the binary data based on a comparison of the determined location of the alignment mark and an original location of the alignment mark.

Abstract: There are provided optical data storage media and methods of optical data storage using the same. The optical data storage media comprises a non-linear sensitizer capable of absorbing actinic radiation to cause upper triplet energy transfer to a reactant that undergoes change upon triplet excitation. The refractive index change (?n) of the medium is at least about 0.005, or even at least about 0.05.

Abstract: An apparatus, system, and method are disclosed for calibrating a holographic storage device. A read channel reads a factory-stored hologram from a holographic media. A calculation module calculates a read difference between the read factory-stored hologram and a first holographic pattern that digitally describes the factory-stored hologram. In one embodiment, a calibration module calibrates the read channel with the read difference.