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Phase-conjugate read-out in a holographic data storage

A data storage and holographic technology, applied in information storage, digital memory information, static memory, etc., can solve problems such as optical and mechanical structure complexity of hologram drive

Inactive Publication Date: 2007-05-30
KONINK PHILIPS ELECTRONICS NV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, this complicates the optical and mechanical structure of the hologram drive

Method used

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Embodiment Construction

[0042] To achieve high density and precise imaging without requiring short focal length lens systems corrected for all aberrations, it has been proposed to use phase-conjugate readout of volume holograms stored on holographic data storage media. After recording the target beam from the SLM with the reference beam, the hologram is reconstructed using the phase-conjugate (time-reversed copy) of the original reference beam. The diffracted wavefront then traces back the path of the incident target beam, canceling out any accumulated phase error. This is done to be able to fetch pages of data with high fidelity for very small systems with low performance lenses or even without any lenses.

[0043] However, the known phase-conjugate readout systems described above with reference to Figures 7(a) and 7(b) of the accompanying drawings cannot produce total reflection devices.

[0044] International patent application WO 03 / 012782 describes a holographic storage device in which two focu...

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Abstract

The invention relates to a holographic data storage medium (4) in which there are sections (20) which are used for data storage and sections (21) which are not. A diffractive structure (30a, 30b) is provided in respect of one or more of the unused sections (21), possibly at each of the boundaries between the used (20) and unused sections (21) or within the volume of a respective unused section (21) of the data storage volume. During read-out, a reference wave (6) is diffracted by the diffractive structure (30b) such that it enters a used section (20) (from the right) in a direction substantially perpendicular to the optical axis (16) of the signal wave (26). During recording, a reference wave (2) is diffracted by the diffractive structure (30a) such that it enters the used section (20) (from the left) in a direction substantially perpendicular to the optical axes (lb) of the signal wave (1).

Description

technical field [0001] The present invention relates to holographic data storage, in particular phase conjugate storage and readout of data. Background technique [0002] Holographic memory is a promising storage technology that uses three-dimensional media to store data. In the case of optical and hard disk storage, the data bits stored on the storage medium can only be read out sequentially, while in the case of page-oriented storage systems, such as holographic data storage systems, the stored data can be accessed one page at a time, That is, a group of N bits is read out at the same time, wherein such a group of N pixels is called a "data page". Storage media may be grouped into spatially separated regions or volumes, each group containing M data pages. Such a group of M data pages is called "workbook" (book), and the process of gradually processing data pages k=1 to k=M in a workbook is called "multiplexing". [0003] Hologram memory is a true three-dimensional stora...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G11B7/0065G11C13/04
CPCG11B7/0065G11C13/042
Inventor S·斯塔林加
Owner KONINK PHILIPS ELECTRONICS NV