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PatentDOI

Holographic storage using shift multiplexing

15 Feb 1995-Optics Letters (Optical Society of America)-Vol. 20, Iss: 7, pp 782-784
TL;DR: In this article, the authors present a method of recording successive holograms in a recording medium, using at least a fan of M waves along at least one first axis with a separation angle between adjacent waves and directing the fan of the M waves as a reference beam along a reference path onto the recording medium.
Abstract: The invention is embodied in a method of recording successive holograms in a recording medium, using at least a fan of M waves along at least a first axis with a separation angle between adjacent waves and directing the fan of M waves as a reference beam along a reference beam path onto the recording medium, successively modulating a wave with a succession of images to produce a succession of signal beams along a signal beam path lying at a propagation angle relative to the reference beam path so that the signal and reference beams intersect at a beam intersection lying within the medium, the beam intersection having a size corresponding to beam areas of the reference and signal beams, producing a succession of relative displacements in a direction parallel to the first axis between the recording medium and the beam intersection of the signal and reference beam paths in synchronism with the succession of signal beams, each of the displacements being less than the size of the intersection whereby to record successive holograms partially overlapped along a direction of the displacements.

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Citations
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Journal ArticleDOI
19 Jul 2004
TL;DR: Fundamental issues underlying holographic data storage: grating formation, recording and readout of thick and thin holograms, multiplexing techniques, signal-to-noise ratio considerations, and read out techniques suitable for conventional, phase conjugate, and associative search data retrieval are discussed.
Abstract: In this paper, we discuss fundamental issues underlying holographic data storage: grating formation, recording and readout of thick and thin holograms, multiplexing techniques, signal-to-noise ratio considerations, and readout techniques suitable for conventional, phase conjugate, and associative search data retrieval. Next, we consider holographic materials characteristics for digital data storage, followed by a discussion on photorefractive media, fixing techniques, and noise in photovoltaic and other media with a local response. Subsequently, we discuss photopolymer materials, followed by a discussion on system tradeoffs and a section on signal processing and en/decoding techniques, succeeded by a discussion on electronic implementations for control, signal encoding, and recovery. We proceed further by presenting significant demonstrations of digital holographic systems. We close by discussing the outlook for future holographic data storage systems and potential applications for which holographic data storage systems would be particularly suited.

337 citations

Journal ArticleDOI
TL;DR: The performance of shift-multiplexed memories is characterized by using a spherical wave as the reference beam and the shift selectivity, the cross talk, the exposure schedule, and the storage density of the method are derived.
Abstract: Shift multiplexing is a holographic storage method particularly suitable for the implementation of holographic disks. We characterize the performance of shift-multiplexed memories by using a spherical wave as the reference beam. We derive the shift selectivity, the cross talk, the exposure schedule, and the storage density of the method. We give experimental results to verify the theoretical predictions.

232 citations

Journal ArticleDOI
TL;DR: The holographic recording and recovery of high-capacity (480-kbit) digital data pages in these media are reported, further illustrating their data-storage capabilities.
Abstract: A general strategy for fabricating thick, optically flat photopolymer recording media with high dynamic range (M/#) that exhibit low levels of recording-induced Bragg detuning for holographic data storage is presented. In particular, media with M/# values as high as 42 in 1-mm-thick formats are obtained. We believe that these results are the first demonstration of a holographic storage medium with a dynamic range of this magnitude. In addition, we report the holographic recording and recovery of high-capacity (480-kbit) digital data pages in these media, further illustrating their data-storage capabilities.

211 citations

Journal ArticleDOI
TL;DR: Several basic architectural concepts along with various multiplexing options and associated techniques for holographic data storage are reviewed.
Abstract: Although the concept of using multiplexed holography for data storage has been considered for some time, recent advances in several critical device technologies along with developments in storage materials have greatly enhanced the likelihood of successful implementations. We review several basic architectural concepts along with various multiplexing options and associated techniques for holographic data storage.

210 citations

Journal ArticleDOI
TL;DR: The performance specifications of a holographic three-dimensional disk system are experimentally characterized and a surface density of 10 bits/µm(2) is experimentally demonstrated with a 100-µM-thick photopolymer as the recording medium.
Abstract: The performance specifications of a holographic three-dimensional disk system are experimentally characterized. A surface density of 10 bits/μm^2 is experimentally demonstrated with a 100-μm-thick photopolymer as the recording medium.

202 citations

References
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Journal ArticleDOI
Fai H. Mok1
TL;DR: As many as 5000 holograms of high-resolution images have been stored within a single crystal of Fe:LiNbO3 using fracture-space multiplexing to increase the storage bandwidth.
Abstract: As many as 5000 holograms of high-resolution images (320 × 220 pixels) have been stored within a single crystal of Fe:LiNbO3. The nominal angle between the reference beam and the object beam was 90°. Fractal-space multiplexing was used to increase the storage bandwidth.

548 citations

Journal ArticleDOI
TL;DR: A volume holographic data storage scheme that employs counterpropagating reference and image beams and wavelength multiplexing for page differentation and a reduction in holographic cross talk is predicted.
Abstract: We propose a volume holographic data storage scheme that employs counterpropagating reference and image beams and wavelength multiplexing for page differentation. This method is compared with that based on angular multiplexing. A reduction in holographic cross talk is predicted. Further cross-talk reduction that is due to sidelobe suppression is observed in experiments by using photorefractive crystals and the proposed orthogonal data storage.

380 citations

Journal ArticleDOI
TL;DR: A novel phase encoding method using deterministic orthogonal phase codes in a reference-based multiplexing technique is obtained that is able to retrieve multiple images with high diffraction efficiency without energy losses, adjustment problems or any time delay.

306 citations

Book
01 Jan 1981

302 citations

PatentDOI
TL;DR: A method of multiplexing holograms by rotating the material or, equivalently, the recording beams is described, and a total of 295 holograms in a 38-microm-thick photopolymer film is multiplexed by combining peristrophicmultiplexing with angle multiplexers.
Abstract: A peristrophic multiplexing system directs a signal light beam and reference light beam onto a selected recording spot in the recording medium. The light beams collectively define a plane of interaction. Either the recording medium or the signal/reference beam are rotated relative to the other through a succession of peristrophic multiplexing angles. Those angles cause relative rotation about an axis that is not perpendicular to the plane of selectivity. The rotation occurs contemporaneously with the modulating of the hologram on the medium.

256 citations