Data storage using light of spatially modulated phase and polarization

• US 10,236,027 B1
• Filed: 02/12/2018
• Issued: 03/19/2019
• Est. Priority Date: 02/12/2018
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Inventors: Georgiou, Andreas, Kollin, Joel Steven, Clegg, James Hilton, Anderson, Patrick Neil
• Primary Examiner(s): Agustin, Peter Vincent
• Application Number:
  US15/894,778
• Time in Patent Office: 400 Days
• Field of Search: None
• CPC Class Codes: G02B 27/1046 for use with transmissive spatial light modulators
• CPC Class Codes: G03H 1/041 Optical element in the object space affecting the object beam, not otherwise provided for
• CPC Class Codes: G03H 1/16 using Fourier transform G03H1/10, G03H1/12, G03H1/14 take precedence; analogue computers G06G, e.g. G06G7/19
• CPC Class Codes: G03H 1/2294 Addressing the hologram to an active spatial light modulator
• CPC Class Codes: G03H 1/26 Processes or apparatus specially adapted to produce multiple sub- holograms or to obtain images from them, e.g. multicolour technique
• CPC Class Codes: G03H 2001/048 Parallel printer, i.e. a fringe pattern is reproduced
• CPC Class Codes: G03H 2001/0482 Interference based printer
• CPC Class Codes: G03H 2001/0484 Arranged to produce three-dimensional fringe pattern
• CPC Class Codes: G03H 2001/2605 Arrangement of the sub-holograms, e.g. partial overlapping
• CPC Class Codes: G03H 2210/30 3D object
• CPC Class Codes: G03H 2223/22 Polariser
• CPC Class Codes: G03H 2225/36 Polarisation
• CPC Class Codes: G03H 2225/60 Multiple SLMs
• CPC Class Codes: G11B 11/10532 Heads
• CPC Class Codes: G11B 7/0045 Recording G11B7/006, G11B7/0065 take precedence
• CPC Class Codes: G11B 7/0065 Recording, reproducing or erasing by using optical interference patterns, e.g. holograms
• CPC Class Codes: G11B 7/127 Lasers; Multiple laser arrays lasers per se H01S
• CPC Class Codes: G11B 7/128 Modulators G11B7/1245 takes precedence
• CPC Class Codes: G11B 7/1372 Lenses
• CPC Class Codes: G11B 7/1395 Beam splitters or combiners G11B7/1353, G11B7/1356 take precedence ; beam splitting or combining per se G02B27/10
• CPC Class Codes: G11B 7/14 : specially adapted to record on, or to reproduce from, more than one track simultaneously

Abstract

An optical data-storage system comprises a laser, an imaging optic, and associated computer logic. The laser is configured to emit a pulsed wavefront having uniform phase and polarization. The imaging optic is configured to modulate the phase and polarization of different portions of the wavefront by different amounts, and to diffract light from the different portions to a substrate with writeable optical properties. The logic is configured to receive data and to control modulation of the phase and polarization such that the light diffracted from the imaging optic writes the data to the substrate.

Claims

1. An optical data-storage system, comprising:

a laser configured to emit a sub-picosecond pulsed wavefront having uniform phase and polarization;

an imaging optic configured to modulate the phase and polarization of different portions of the wavefront by different amounts, and to diffract light from the different portions to a substrate with writeable optical properties, the imaging optic being configured to modulate the different portions of the wavefront to different near-field polarizations and to image the light to an array of substrate voxels at different far-field polarizations; and

operatively coupled to the imaging optic, logic configured to receive data and to control modulation of the phase and polarization such that the light diffracted from the imaging optic writes the data to the substrate.

2. The optical data-storage system of claim 1 wherein the data includes inequivalent first and second data values written simultaneously by the light diffracted from the imaging optic, wherein the first data value is written to a first voxel by light of a first far-field polarization, and wherein the second data value is written to a second voxel by light of a second far-field polarization.

3. The optical data-storage system of claim 2 wherein each data value written to the substrate is characterized by one of R≥

1 different amplitude values of the diffracted light at each of Q≥

1 different far-field polarizations.

4. The optical data-storage system of claim 3 wherein the each of Q≥

1 different far-field polarization determines a slow axis orientation at the voxel where the data value is written, and wherein the one of R≥

1 different amplitude values determines a retardance at the voxel where the data value is written.

5. The optical data-storage system of claim 1 wherein the substrate comprises glass.

6. The optical data-storage system of claim 1 wherein the pulsed wavefront comprises pulses of 100 femtoseconds or less.

7. The optical data-storage system of claim 1 wherein the imaging optic is a liquid-crystal spatial light modulator (LCSLM) having an array of pixel elements configured to modulate the phase and polarization of different portions of the wavefront by different amounts, and to diffract the light from the different portions to the substrate.

8. The optical data-storage system of claim 7 wherein the LCSLM includes two independently addressable electrodes per pixel element and is configured to modulate the phase independent of the polarization.

9. The optical data-storage system of claim 1 wherein the imaging optic is configured to modulate the phase in correlation with the polarization.

10. The optical data-storage system of claim 1 wherein the logic is configured to execute a holographic-design algorithm to control modulation of the phase and polarization.

11. An optical data-storage system, comprising:

a laser configured to emit a pulsed wavefront having uniform phase and polarization;

a liquid-crystal spatial light modulator (LCSLM) having an array of pixel elements configured to modulate the phase and polarization of different portions of the wavefront by different amounts, and to diffract light from the different portions to a substrate with writeable optical properties; and

operatively coupled to the LCSLM, logic configured to receive data and to control modulation of the phase and polarization such that the light diffracted from the LCSLM writes the data to the substrate,

wherein the LCSLM is configured to modulate the different portions of the wavefront to different near-field polarizations and to image the light to an array of substrate voxels at different far-field polarizations, wherein the data includes inequivalent first and second birefringence values written simultaneously by the light diffracted from the LCSLM, wherein the first birefringence value is written to a first voxel by light of a first far-field polarization, and wherein the second birefringence value is written to a second voxel by light of a second far-field polarization.

12. The optical data-storage system of claim 11 wherein the LCSLM is configured to modulate the phase in correlation with the polarization.

13. The optical data-storage system of claim 11 wherein the logic is configured to execute a holographic-design algorithm to control modulation of the phase and polarization.

14. The optical data-storage system of claim 13 wherein the holographic-design algorithm is based on a Gerchberg-Saxton algorithm.

15. The optical data-storage system of claim 13 wherein the holographic-design algorithm is based on a Direct Binary Search algorithm.

16. The optical data-storage system of claim 11 further comprising a polarization-modulating sheet arranged between the laser and the LCSLM, the polarization-modulating sheet comprising a tiling of cells arranged in registry with the pixel elements of the array, each cell configured to rotate the polarization of a portion of the wavefront passing through that cell.

17. An optical data-storage system, comprising:

a laser configured to emit a pulsed wavefront having uniform phase and polarization;

a liquid-crystal spatial light modulator (LCSLM) having an array of pixel elements configured to modulate the phase and polarization of different portions of the wavefront by different amounts, and to diffract light from the different portions to a substrate with writeable optical properties, each pixel element having first and second independently addressable electrodes; and

operatively coupled to the first and second electrodes of each pixel element, logic configured to receive data and to control modulation of the phase and polarization such that the light diffracted from the LCSLM writes the data to the substrate,

wherein an average voltage applied to the first and second electrodes of a pixel element of the LCSLM affects a phase of a first component of the portion of the wavefront passing through that element, and wherein a differential voltage between the first and second electrodes affects a phase of a non-parallel second component of the portion of the wavefront passing through that element.