1645results about "Recording/reproducing/erasing using optical interference patterns" patented technology

According to one aspect, a holographic storage system including micro-actuators is presented. In one example of one aspect of the invention, the device includes a spatial light modulator, a detector, a storage medium, and at least one micro-actuator configured to move at least one of the spatial light modulator, the detector, and the storage medium. The micro-actuators may include a servomechanism or the like to control the positioning of a component based on feedback associated with a misalignment of a detected image. According to another aspect of the invention, various methods for determining component misalignments of a holographic storage system are presented.

Disclosed is a multiplexing method and apparatus that allows holograms to be spatially multiplexed with partial spatial overlap between neighboring stacks of holograms. Each individual stack can additionally take full advantage of an alternate multiplexing scheme such as angle, wavelength, phase code, peristrophic, or fractal multiplexing, for example. An amount equal to the beam waist of the signal beam writing a hologram separates individual stacks of holograms. Upon reconstruction, a hologram and its neighbors will all be readout simultaneously. An filter is placed at the beam waist of the reconstructed data such that the neighbors that are read out are not transmitted to the camera plane. Alternatively, these unwanted reconstructions can be filtered out with an angular filter at an intermediate plane in the optical system that has a limited angular passband.

A method for processing data pixels in a holographic data storage system is disclosed. The method includes assigning predetermined reserved blocks throughout each data page, where each reserved block comprises known pixel patterns, determining position errors of the data page by computing the best match between regions of the data page and the predetermined reserved blocks, and compensating the data pixels at the detector in accordance with the corresponding position errors of the data page.

A holographic recording medium exhibiting a high recording sensitivity without execution of reduction treatment. A system records information on the holographic recording medium by using a gating light within a wavelength band causing less optical damage to the holographic recording medium. The holographic recording medium includes a single crystal of lithium niobate (LiNbO3) or lithium tantalate (LiTaO3) containing Mn as a dopant.

Holographic storage media including a substrate and a dye material capable of undergoing a photo-induced change are disclosed. Data may be written into the holographic storage media using light of one wavelength and read using light of a different wavelength.

A holographic recording and reconstructing apparatus includes a light source having a variable oscillation wavelength; a temperature sensing unit operable to sense temperature; and a control unit operable to record information about a temperature sensed by the temperature sensing unit on a holographic recording medium during recording, to obtain the information about the temperature from the holographic recording medium and obtain a temperature sensed by the temperature sensing unit during reconstruction, to determine the amount of wavelength shift to counteract the effects of a change in the dimension of the holographic recording medium between recording and reconstruction based on the difference between the temperatures, and to shift the oscillation wavelength of the light source by the determined amount.

An optical storage system suitable for optical storage and retrieval of information using a storage medium comprising a substrate, an active layer for retention of the data, and an overlying optical layer, or layers for double-sided. The optical layer serves to produce an evanescent field in or adjacent to the active layer in response to an incident beam of radiation. The evanescent field is frustrated or attenuated by the data in the active layer and produces a signal.

A holographic storage apparatus for recording data in a holographic medium includes at least one light source for generating a reference beam and a signal beam. The reference beam is preferably a phase beam of unchanging phase content. The apparatus also includes a holographic medium placed in a path of the reference beam and a path of the signal beam. The holographic medium has a first face and both the reference beam and the signal beam enter the holographic medium through the first face. The holographic medium also includes a data reflective surface. The reference beam and the signal beam interfere in the holographic medium to create a hologram only after at least one of the reference beam and the signal beam have reflected off of the data reflective surface.

An apparatus for writing and reading holograms, comprising a spatial light modulator (SLM) operable in phase mode, having a plurality of pixels for generating an object beam that overlaps with a reference beam; a holographic recording medium (HRM) in the path of the object beam; and a first lens element disposed in the path of the object beam between the SLM and the HRM; wherein the HRM is disposed at or near the Fourier transform plane of the first lens element.

Calibration of holographic data storage systems (HDSS) is provided by utilizing holographic media (4) having calibration features which can be read, written, or read and written by a HDSS (30). Calibration features may represent for example, surface-relief gratings, holographic recordings, amplitude varying regions, or magnetic regions, or a combination thereof, at locations on or within the media. One or more of the calibration features along media region (302) are media calibration features with media and format information, and other calibration features along region (301) are system calibration features for optically and mechanically aligning HDSS optics. The media (4) may have performance calibration features along region (307) which can be recorded by a HDSS and then read back to determine characteristics of the media. Different HDSS systems can read the calibration features of the media (4) when installed in each HDSS to obtain information about the media, and to optically and mechanically align the media for optimal operation with the media.

The present invention provides an optical information recording device and reproduction device which enable accurate recording and reproduction of information. The present invention comprises a light source 103, a deflection element 109 for changing the traveling direction of light emitted from the light source, a means 113 for generating information light holding information using light of which the traveling direction has been changed by the deflection element, a means 113 for generating recording reference light using light of which the traveling direction has been changed by the deflection element, an objective lens 127 for irradiating information light and recording reference light to the moving recording medium 151, and a control means 163 for controlling the deflection element and enabling the irradiation position of the objective lens 127 to the recording medium 151 to follow the movement of the recording medium 151.

The present invention relates to embodiments of a process for subjecting a holographic storage medium to illuminative treatment to: (1) enhance or optimize recording of holographic data; (2) enhance or optimize reading of recorded holographic data; and / or (3) erase recorded holographic data. The present invention also relates to embodiments of a system comprising: (a) an illuminative treatment beam; (b) means for reducing the coherence of the beam and (c) means for transmitting the reduced coherence beam to cause illuminative treatment of: (1) an unrecorded portion of a holographic storage medium to provide pre-cured portions having increased ability to stably record holographic data; (2) a recorded portion of a holographic storage medium to provide a post-cured portion having reduced residual sensitivity; and / or (3) a recorded portion of a holographic storage medium having holographic data to provide an erased portion wherein at least some of the recorded holographic data is erased.

A hologram recording medium has a transparent substrate having an incidence surface, on which a write beam and a reference beam are made incident, and a servo surface opposite to the incidence surface, the servo surface including a header section and a data section, a reflecting layer formed on the servo surface of the transparent substrate, and a hologram recording layer provided on the incidence surface of the transparent substrate, the servo surface having intermittent tracking grooves in the data section except for recording positions, and a width of the tracking grooves being set at a value to less than an e−2 diameter of the reference beam.

The invention relates to novel aromatic urethane (meth)acrylates having a high refractive index, a process for the preparation thereof and a process for the production of holographic media.

An optical information recording device, a reproduction device, and a method enabling include a first spatial light modulator I for generating information light by spatially modulating light from a light source 143 by a plurality of pixels and a second spatial light modulator R for generating reference light by spatially modulating light from a light source by a plurality of pixels. The area I of the information light and the area R of the reference light on the entrance pupil surface of an objective lens 111 are formed such that one area surrounds the other area. The reference light is spatially modulated by the second spatial light modulator R such that interference is not easily generated between the reference lights in the information recording layer 3.

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. The positioning of the information light and the reference light for recording is carried out based on information recorded in address servo areas (6).

Holographic data storage devices are presented. The holographic data storage device includes an optically transparent substrate, wherein the optically transparent substrate includes a photochemically active dye and a heat generating chromophore. Methods for making holographic data storage device are also presented.

A novel polymerizable high-refractive index compound which is useful as an optical material, and a holographic recording medium using the same, which has high diffraction efficiency, high light transmittance and small rate of shrinkage, are provided. A composition for forming a holographic recording layer containing a reactive compound represented by the following formula 1, a holograph recording material, and a holographic recording medium provided with a recording layer containing the same, are disclosed.(In the formula (1),A is an optionally substituted ring;Ar is an optionally substituted (hetero)aryl group formed by condensation of two or more rings;R is hydrogen or a methyl group;n is an integer of from 1 to 7; andwhen n is 2 or more, then plural Ars may be the same as or different from each other,provided that when A is an aromatic heterocyclic ring, and Ar is an optionally substituted (hetero)aryl group formed by condensation of two or more rings, then in the structure in which A and Ar are connected with each other, those partial structures that are in the structure of each of A and Ar, and are connected directly with each other, do not contain a heteroatom.)

Methods and systems are provided for obtaining a phase conjugate reconstruction beam for use in retrieving holographic information from a holographic storage medium. These methods and systems include generating a coherent light beam that is a reproduction of the reference beam used in storing the holographic information in the storage medium. This coherent light beam is then directed through the holographic storage medium at the same angle and location of the reference beam during recording of the hologram. The directed coherent beam is then reflected back through the storage medium so that the reflected coherent light beam provides a phase conjugate of the reference beam and passes through the storage medium at the same angle and location that the reference beam passed through the storage medium during recordation of the hologram.

According to one aspect and example, a holographic recording system includes a light source, an object for modulating an object beam from the light source, and a relay system adapted to magnify (positive or negative) the modulated beam (e.g., an image of the object) to an output image. The object may include an SLM operable to modulate the object beam with an information layer comprising a plurality of data pages. The output image is directed to the holographic storage medium, where a reference beam is also directed, to record the resulting interference pattern. Additionally, the relay system converges the output image to an output Fourier plane, which may be disposed within the holographic storage medium. A filter may be placed at an intermediate Fourier plane located prior to the output Fourier plane, and a phase mask may be placed at the position of the output image.

According to one aspect, methods and systems for recording and reading holographic storage media are provided. In one aspect, a method includes illuminating a data mask with a beam and recording a resulting modulated beam in a holographic storage medium, wherein the data mask includes an information layer that is divided into multiple data pages, and propagating a reference beam to the holographic storage medium to record the multiple data pages of the data mask in a parallel fashion on the holographic storage medium.

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.

The present invention provides a hologram recording material which is not required to be subjected to pre-exposure treatment at the time of recording, attains high refractive index change, high sensitivity, low scattering, environment resistance, durability, low dimensional change, and high multiplicity, and is suitable for volume hologram recording. Also, the present invention provides a hologram recording medium. A hologram recording material comprising a matrix material having a softening temperature of 50° C. or higher, and a photopolymerizable monomer which is in a liquid phase state at room temperature. The matrix material is preferably contained in an amount of 50% by weight or more and 90% by weight or less of the whole of the hologram recording material. A softening temperature of the hologram recording material is preferably 0° C. or higher.

A method for holographic storage data recovery in a holographic storage system is presented. One exemplary method includes detecting a stored image at a detector such that the image is oversampled. A relationship is determined between a location of the detected image and a location of the source image. Pixel information associated with the source image may be obtained from the detected image based on a fractional delay filter. In one example, the image may be oversampled by magnifying the detected image at the detector and / or having a detector with pixel sizes and spacing less than the image pixel size. Further, coefficients of the fractional delay filter may be determined, at least in part, on magnification and shift information of the image based on known registration marks.

There is provided a hologram reconstruction method including: onto an optical recording medium in which a hologram is recorded by simultaneously irradiating the Fourier transformed signal beam representing a digital data with a bright and dark image and removing a DC component and the Fourier transformed reference beam thereon, irradiating a first reference beam for reading out that is the same as the reference beam to generate a first diffracted light generated by the recorded hologram, and synthesizing a DC component of a predetermined phase with the generated first diffracted light to generate a first synthesized light; detecting an inverse Fourier transformed image of the first synthesized light to obtain first image data; irradiating a second reference beam for reading out that differs from the reference beam onto the hologram recorded on the optical recording medium to generate a second diffracted light from the recorded hologram, and synthesizing a DC component of a predetermined phase with the generated second diffracted light to generate a second synthesized light; detecting an inverse Fourier transformed image of the second synthesized light to obtain second image data; subtracting one of the first image data and the second image data from the other at each pixel of the light and dark image; and decoding the digital data based on the value obtained by subtraction.