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JP-2026514326-A - Phase-modulated optical data storage

JP2026514326AJP 2026514326 AJP2026514326 AJP 2026514326AJP-2026514326-A

Abstract

A method for writing data to a transparent substrate includes forming a first voxel by focusing a first laser pulse at a first location within the transparent substrate, and forming a second voxel by focusing a second laser pulse at a second location within the transparent substrate. The first and second laser pulses have different amplitudes, thereby resulting in first and second voxels having different intensities. A system useful for implementing this method, an optical data storage medium obtained by this method, and a method for reading data from the optical data storage medium are also provided.

Inventors

  • ウィンクラー，トーマス トルステン
  • ブラック，リチャード ジョン
  • サカクラ，マサアキ
  • イリエヴァ，テオドラ
  • クーパー，ブリジット ロザンナ ドリス
  • ステファノヴィチ，イオアン アレクサンドル
  • アラナス，エリカ ブランカダ
  • ベレンゲル，パブロ ラファエル アンドレアス ウィルケ
  • ドゥレヴィンスカス，ロカス
  • ゴメス ディアス，アリエル
  • ウィテカー，チャールズ アーネスト
  • ディーガン，ティモシー ジョン
  • クレッグ，ジェームス ヒルトン
  • クレザロー，ダニエル ジョナサン フィンチリー
  • ウィリアムズ，ヒュー デイビッド ポール
  • ドネリー，オースティン ニコラス

Assignees

  • マイクロソフト テクノロジー ライセンシング，エルエルシー

Dates

Publication Date
20260511
Application Date
20240313
Priority Date
20230331

Claims (20)

  1. (101) A first voxel (220) having a first intensity is formed by focusing a first laser pulse at a first location within a transparent substrate (200), wherein the first laser pulse has a first amplitude (101), (102) A second voxel (222) having a second intensity different from the first intensity is formed by focusing a second laser pulse at a second location within the transparent substrate (200), wherein the second laser pulse has a second amplitude different from the first amplitude (102), Methods that include...
  2. The method according to claim 1, wherein the first location is spaced from the second location by a distance selected such that the first voxel and the second voxel partially overlap.
  3. The method according to claim 1 or 2, further comprising focusing a third laser pulse at a third location within the transparent substrate to form a third voxel (320c), wherein the third voxel (320c) has an intensity equal to that of the first voxel (320a).
  4. The method according to claim 3, wherein the first voxel (320a) and the third voxel (320c) have different shapes.
  5. The method according to claim 3 or 4, wherein the first voxel (320a) is spaced by a first lateral distance from the scan axis (340), the third voxel (320c) is spaced by a third lateral distance from the scan axis (340), and the first and third lateral distances are different.
  6. The method according to any one of claims 1 to 5, wherein each voxel (220, 222) is formed by a single laser pulse.
  7. The method according to any one of claims 1 to 6, wherein the transparent substrate (200) includes glass.
  8. The method according to claim 7, wherein the glass is borosilicate glass or soda-lime glass.
  9. The method according to any one of claims 1 to 8, comprising forming at least two layers (230, 232) of voxels (220, 222) within the transparent substrate (200).
  10. The method according to claim 9, comprising forming at least 100 layers of voxels (220, 222) within the transparent substrate (200).
  11. The method according to any one of claims 1 to 10, comprising simultaneously forming at least two first voxels (220) at their respective first locations.
  12. The method according to any one of claims 1 to 11, comprising forming a plurality of voxels positioned as reference marks.
  13. A transparent substrate (200) containing a material having a bulk refractive index, A first voxel (220) embedded in the transparent substrate (200), wherein the first voxel (220) has a first strength, A second voxel (222) embedded in the transparent substrate (200), wherein the second voxel (222) has a second intensity different from the first intensity, thereby resulting in the first and second voxels (220, 222) encoding different data symbols, An optical data storage medium (200) comprising the above.
  14. The first and second voxels (220, 222) are heterogeneous voxels, and each of them is A positive sublayer having a refractive index greater than that of the bulk refractive index, A negative sublayer having a refractive index smaller than the bulk refractive index, An optical data storage medium according to claim 13, comprising the above.
  15. The optical data storage medium according to claim 13 or 14, wherein the first and second voxels (220, 222) are arranged to overlap.
  16. The optical data storage medium according to any one of claims 13 to 15, wherein the first and second voxels (220, 222) have different shapes.
  17. Controller (600) and A pulsed laser source (510), A first amplitude modulator (522) is located downstream of the pulsed laser source (510) on the optical path, A system (500) comprising, The controller (600) is operably linked to the amplitude modulator (522), and when in use, (101) A first voxel (220) having a first intensity is formed by focusing a first laser pulse at a first location within a transparent substrate (200), wherein the first laser pulse has a first amplitude (101), (102) A second voxel (222) having a second intensity different from the first intensity is formed by focusing a second laser pulse at a second location within the transparent substrate (200), wherein the second laser pulse has a second amplitude different from the first amplitude (102), A system (500) that causes the system (500) to perform a method including the above.
  18. The system according to claim 17, further comprising a scanner (524) positioned downstream of the amplitude modulator (522) on the optical path.
  19. A beam splitter (512) is positioned between the pulse laser source (510) and the first amplitude modulator (522), A second amplitude modulator is arranged in parallel with the first amplitude modulator, Furthermore, The system according to claim 17 or 18, wherein the second amplitude modulator is operablely linked to the controller (600), and in use, the controller (600) controls the system (500) to perform a method further comprising forming the first voxel and simultaneously focusing a third laser pulse to a third location in the transparent substrate (200) to form a third voxel.
  20. The system according to any one of claims 17 to 19, further comprising a movable sample stage (530) for holding the transparent substrate (200).

Description

background [0001] There is considerable demand for data storage. Cloud storage providers are estimated to need data storage capacity on the order of zettabytes (one zettabyte is one trillion gigabytes ( 10²¹ bytes)) in the near future. Much of the data needs to be stored for long periods of time. [0002] Examples of currently widely used data storage technologies include hard disk drives, magnetic tape, flash memory, and optical discs. All of these technologies have the drawback that data must be periodically copied to replacement media. This is costly in terms of both energy consumption and hardware requirements. [0003] Magnetic storage media such as hard drives and magnetic tapes suffer from the problem of gradual demagnetization. Flash memory is subjected to read disturb effects, which cause failure of surrounding flash cells due to repeated reading from a particular flash cell. Reflective materials used for data storage in optical media such as DVDs degrade over time. [0004] As a solution to these drawbacks, birefringent optical data storage media have been proposed. Birefringent optical data storage media comprise a substrate such as a quartz glass substrate. Data is encoded in three-dimensional nanostructures formed within the substrate. These nanostructures are called voxels. [0005] Voxels have different optical properties than those of the surrounding bulk substrate. Birefringent voxels exhibit different refractive indices depending on the polarization and/or direction of the incident light. Birefringence can be controlled when writing voxels to the substrate and is used to encode data. [0006] The substrate is transparent in the sense that it is transparent to one or more wavelengths of light used for reading and writing voxels. [0007] Birefringent optical data storage media and their manufacture are described, for example, in Anderson et al., Glass: A New Media for a New Era? 10th USENIX Workshop on Hot Topics in Storage and File Systems (HotStorage 18), 2018, and U.S. Patent No. 10,236,027B1. overview [0008] In one embodiment, a method is provided for writing data to a transparent substrate. This method includes forming a first voxel having a first intensity by focusing a first laser pulse to a first location in the transparent substrate, wherein the first laser pulse has a first amplitude, and forming a second voxel having a second intensity different from the first intensity by focusing a second laser pulse to a second location in the transparent substrate, wherein the second laser pulse has a second amplitude different from the first amplitude. By encoding the data by amplitude modulation, it is possible to write voxels using a single laser pulse, thereby increasing data throughput. Alternatively or additionally, this method can reliably form voxels on inexpensive substrates such as borosilicate glass. [0009] In another embodiment, an optical data storage medium is provided. The optical data storage medium comprises a transparent substrate containing a material having a bulk refractive index, a first voxel embedded in the transparent substrate having a first intensity, and a second voxel embedded in the transparent substrate having a second intensity different from the first intensity, thereby resulting in a first voxel and a second voxel encoding different data symbols. The transparent substrate can be obtained by methods such as those described herein. [0010] Another embodiment provides a system for writing phase voxels onto a transparent substrate. This system is useful for implementing methods such as those described herein. This system comprises a controller, a pulsed laser source, and a first amplitude modulator located downstream of the pulsed laser source in the optical path. The amplitude modulator is operably linked to the controller. The controller is configured to cause the system to perform methods such as those provided herein. [0011] Further embodiments provide a method for reading data from an optical data storage medium as defined herein. This method includes capturing an image of voxels using a refractive index-sensitive microscope and processing the image using a processor to reconstruct the data. Portions of the image having different signal strengths encode different data symbols. [0012] This specification also provides the use of amplitude modulation for encoding multiple different data symbols as voxels within a transparent substrate. [0013] This summary is provided to introduce, in a simplified form, the concepts that will be further described below in the detailed description. This summary is not intended to identify any major or essential features of the claimed invention, nor is it intended to be used to limit the scope of the claimed invention. Furthermore, the claimed invention is not limited to any implementation that solves any or all of the disadvantages described herein. Brief explanation of the drawing [0014] To aid in understanding embodiments of the present di