US20140204437A1 - Dynamic aperture holographic multiplexing - Google Patents

Dynamic aperture holographic multiplexing Download PDF

Info

Publication number
US20140204437A1
US20140204437A1 US13/875,071 US201313875071A US2014204437A1 US 20140204437 A1 US20140204437 A1 US 20140204437A1 US 201313875071 A US201313875071 A US 201313875071A US 2014204437 A1 US2014204437 A1 US 2014204437A1
Authority
US
United States
Prior art keywords
angular aperture
aperture
signal beam
angle
signal
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US13/875,071
Other languages
English (en)
Inventor
Mark R. Ayres
Kenneth E. Anderson
Fredric R. Askham
Bradley Jay SISSOM
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Akonia Holographics LLC
Original Assignee
Akonia Holographics LLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Akonia Holographics LLC filed Critical Akonia Holographics LLC
Priority to US13/875,071 priority Critical patent/US20140204437A1/en
Assigned to AKONIA HOLOGRAPHICS LLC reassignment AKONIA HOLOGRAPHICS LLC ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: ANDERSON, KENNETH E., ASKHAM, FREDRIC R., AYRES, MARK R., SISSOM, BRADLEY J.
Priority to US14/385,469 priority patent/US9760061B2/en
Priority to JP2015554300A priority patent/JP2016510931A/ja
Priority to EP14743821.2A priority patent/EP2948948A4/en
Priority to PCT/IB2014/060014 priority patent/WO2014115129A2/en
Priority to KR1020147031165A priority patent/KR101526836B1/ko
Publication of US20140204437A1 publication Critical patent/US20140204437A1/en
Abandoned legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
    • G03H1/26—Processes or apparatus specially adapted to produce multiple sub- holograms or to obtain images from them, e.g. multicolour technique
    • G03H1/2645—Multiplexing processes, e.g. aperture, shift, or wavefront multiplexing
    • G03H1/265—Angle multiplexing; Multichannel holograms
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
    • G03H1/02—Details of features involved during the holographic process; Replication of holograms without interference recording
    • G03H1/024—Hologram nature or properties
    • G03H1/0248—Volume holograms
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
    • G03H1/26—Processes or apparatus specially adapted to produce multiple sub- holograms or to obtain images from them, e.g. multicolour technique
    • G03H1/2645—Multiplexing processes, e.g. aperture, shift, or wavefront multiplexing
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/004—Recording, reproducing or erasing methods; Read, write or erase circuits therefor
    • G11B7/0065—Recording, reproducing or erasing by using optical interference patterns, e.g. holograms
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/007—Arrangement of the information on the record carrier, e.g. form of tracks, actual track shape, e.g. wobbled, or cross-section, e.g. v-shaped; Sequential information structures, e.g. sectoring or header formats within a track
    • G11B7/00772—Arrangement of the information on the record carrier, e.g. form of tracks, actual track shape, e.g. wobbled, or cross-section, e.g. v-shaped; Sequential information structures, e.g. sectoring or header formats within a track on record carriers storing information in the form of optical interference patterns, e.g. holograms
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
    • G11B7/135—Means for guiding the beam from the source to the record carrier or from the record carrier to the detector
    • G11B7/1381—Non-lens elements for altering the properties of the beam, e.g. knife edges, slits, filters or stops
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
    • G03H1/26—Processes or apparatus specially adapted to produce multiple sub- holograms or to obtain images from them, e.g. multicolour technique
    • G03H1/2645—Multiplexing processes, e.g. aperture, shift, or wavefront multiplexing
    • G03H2001/267—Polarisation multiplexing

Definitions

  • the present disclosure relates generally to holography and, more specifically, to holographic multiplexing.
  • Holography is a technique for storing both phase and amplitude information of light by recording the interference pattern generated between a coherent object beam and a reference beam as a hologram in a photosensitive medium.
  • a probe beam which is a replica of the reference beam
  • a diffracted beam which is a replica of the object beam
  • the object and reference beams shared an optical axis, creating a diffracted “ambiguity” beam from the conjugate interference term, as well as resulting in a superposition of the diffracted beam with the probe beam.
  • Holography is attractive for digital data storage because many holograms may be written into the same volume (or overlapping volumes) of a thick recording medium using a process known as multiplexing, which is described by G. Barbastathis and D. Psaltis, “Volume holographic multiplexing methods,” in Holographic Data Storage , H. J. Coufal, D. Psaltis, and G. Sincerbox, eds. Springer (2000), pp. 21-62. Many different holographic multiplexing techniques have been developed. For example, using angle multiplexing, described by F. H. Mok, “Angle-multiplexed storage of 5000 holograms in lithium niobate,” Opt. Lett.
  • each hologram may record a different object beam (or signal beam) that has been modulated with a different digital data pattern.
  • the hologram may be illuminated by a probe beam. Due to the Bragg effect, only a hologram recorded with a reference beam angle at the same angle of incidence as the probe beam will produce substantial diffraction.
  • Each signal beam may thus be reconstructed independently, allowing the digital data to be recovered without cross-talk from the rest of the multiplexed holograms.
  • holographic multiplexing techniques such as wavelength multiplexing described by D. Lande, J. F. Heanue, M. C. Bashaw, and L. Hesselink, “Digital wavelength-multiplexed holographic data storage system,” Opt. Lett. 21, 1780-1782 (1996), shift multiplexing described by D. Psaltis, A. Pu, M. Levene, K. Curtis, and G. Barbastathis, “Holographic storage using shift multiplexing,” Opt. Lett. 20, 782-784 (1995), and polytopic multiplexing described by K. Anderson and K. Curtis, “Polytopic multiplexing,” Opt. Lett. 29, 1402-1404 (2004), have been developed. These multiplexing techniques may be used alone or in combination with other multiplexing techniques to increase the amount of data stored in a recording medium.
  • a page-oriented system is one in which the signal beam is modulated as a two-dimensional array of pixels, the modulation typically being imparted by a spatial light modulator (SLM).
  • SLM spatial light modulator
  • a Fourier architecture is one in which the recording medium is placed at or near an optical Fourier plane of the page image.
  • a monocular system is one in which both the reference and signal beams pass through a single, shared objective lens before illuminating the recording medium, as described in U.S. Pat. No. 7,742,209, “Monocular holographic data storage system architecture,” Jun. 22, 2010.
  • One example method may include: recording a first hologram of the set of multiplexed holograms to a recording medium using a first signal beam angular aperture and a first reference beam; and recording a second hologram of the set of multiplexed holograms to the recording medium using a second signal beam angular aperture and a second reference beam, wherein the second signal beam angular aperture is varied in at least one characteristic from the first signal beam angular aperture.
  • the first hologram and the second hologram may each comprise a data page of pixel information.
  • the first signal beam angular aperture and the second signal beam angular aperture may vary in one or more of shape, size, and position.
  • the method may further include: recording a third hologram of the set of multiplexed holograms to the recording medium using a third signal beam angular aperture and a third reference beam, wherein the third signal beam angular aperture may be varied in at least one characteristic from the first signal beam angular aperture and the second signal beam angular aperture; and recording a fourth hologram of the set of multiplexed holograms to the recording medium using a fourth signal beam angular aperture and a fourth reference beam, wherein the fourth signal beam angular aperture may be varied in at least one characteristic from the first signal beam angular aperture, second signal beam angular aperture, and the third signal beam angular aperture.
  • an edge of the first signal beam angular aperture may be separated from an angular aperture of the first reference beam by a first angle; an edge of the second signal beam angular aperture may be separated from an angular aperture of the second reference beam by a second angle; an edge of the third signal beam angular aperture may be separated from an angular aperture of the third reference beam by a third angle; and an edge of the fourth signal beam angular aperture may be separated from an angular aperture of the fourth reference beam by a fourth angle.
  • the first angle, the second angle, the third angle, and the fourth angle may be substantially equal.
  • the first angle and the third angle may be substantially equal; the second angle and the fourth angle may be substantially equal; and the first angle and the third angle may be different than the second angle and the fourth angle.
  • using the first signal beam angular aperture may include using a signal beam with an angular range.
  • at least a portion of an angular locus of a set of reference beams used to record the set of multiplexed holograms may overlap at least a portion of an angular locus of a set of signal beams used to record the set of multiplexed holograms.
  • a first portion of the set of multiplexed holograms may be used to store error parity data and a second portion of the set of multiplexed holograms may be used to store input data, wherein the holograms of the first portion may be smaller than the holograms of the second portion.
  • FIGS. 1( a ) and 1 ( b ) illustrate real and k-space distributions of holographic recording terms.
  • FIG. 2( a ) illustrates an example holographic data storage system having a monocular architecture.
  • FIG. 2( b ) illustrates an example angular aperture map of the monocular system of FIG. 2( a ).
  • FIG. 3( a ) illustrates an example angular aperture map of a monocular system.
  • FIG. 3( b ) illustrates an example angular aperture map of a monocular system implementing dynamic aperture holographic multiplexing.
  • FIG. 4( a ) illustrates an example graph showing the relationship between user capacity and the number of multiplexed holograms, and the relationship between the average number of recorded pixels per hologram and the number of multiplexed holograms.
  • FIG. 4( b ) illustrates an example graph showing the relationship between the reference angle and the multiplexed hologram number, and the relationship between the angular spacing and the multiplexed hologram number.
  • FIG. 5 illustrates a system diagram for an example holographic data storage system for performing dynamic aperture holographic multiplexing.
  • FIG. 6( a ) illustrates an example k-space distribution of holographic recording terms obtained using angle multiplexing.
  • FIG. 6( b ) illustrates an example k-space distribution of holographic recording terms obtained using angle multiplexing and dynamic aperture holographic multiplexing.
  • FIG. 7 illustrates an example k-space distribution of holographic recording terms obtained using dynamic aperture equalization.
  • FIGS. 8( a ) and 8 ( b ) illustrate example angular aperture maps using multiple locus aperture sharing.
  • FIG. 9 illustrates a system diagram for an example collinear holographic data storage system for performing dynamic aperture holographic multiplexing.
  • FIG. 10 illustrates an example SLM pattern and angular aperture map for collinear recording.
  • FIGS. 11( a )-( c ) illustrate an example scheme for performing dynamic aperture holographic multiplexing using a collinear system.
  • FIG. 12 illustrates an example process for performing dynamic aperture holographic multiplexing.
  • FIG. 13 illustrates an example computing system.
  • One example dynamic aperture holographic multiplexing process may include recording a set of holograms in a recording medium by varying both the angular aperture of a reference beam and the angular aperture of a signal beam.
  • the angular aperture of the signal beam may be dynamically changed such that the closest edge of each signal beam angular aperture is selected to be a threshold angle different than the reference beam angular aperture used to record it.
  • the reference beam locus e.g., the aggregate coverage of the individual reference beam angular apertures
  • the signal beam locus e.g., the aggregate coverage of the individual signal beam angular apertures
  • the dynamic aperture holographic multiplexing process may include dynamic aperture equalization to reduce cross-talk, to improve error correction parity distribution for improved recovery transfer rate, to provide multiple locus aperture sharing for increased recording density, and to provide polarization multiplexed shared aperture multiplexing for increased transfer rate in both recording and recovery.
  • the processes for dynamic aperture holographic multiplexing may be combined with other multiplexing techniques, such as angle multiplexing, polytopic multiplexing, and the like.
  • other multiplexing techniques such as angle multiplexing, polytopic multiplexing, and the like.
  • a page-oriented, monocular, Fourier geometry may be used to perform dynamic aperture holographic multiplexing.
  • dynamic aperture holographic multiplexing may similarly be used with other architectures, such as collinear holography systems, common aperture holography systems, and the like.
  • Holographic recording and diffraction can be analyzed using k-space formalism, as described in M. R. Ayres, “k-Space Formalism,” in K. Curtis, L. Dhar, W. L. Wilson, A. Hill, M. R. Ayres, Holographic Data Storage: From Theory to Practical Systems , John Wiley & Sons, Ltd. (2010), pp. 26-31.
  • k-space propagating optical waves and holographic gratings may be represented by three-dimensional Fourier transforms of their distributions in real space.
  • a collimated monochromatic reference beam can be represented in real space and k-space by
  • a r is the complex amplitude of the field
  • ⁇ right arrow over (k) ⁇ r is a vector whose length indicates the spatial frequency of the light waves, and whose direction indicates the direction of propagation.
  • all beams may be composed of light of the same wavelength, so all optical k-vectors may have the same length (e.g.,
  • k n ).
  • all optical propagation vectors may lie on a sphere of radius k n . This construct is known as the k-sphere.
  • Holograms for data storage usually include spatial variations of the index of refraction within the recording medium, typically denoted ⁇ n( ⁇ right arrow over (r) ⁇ ). Ideally, this index modulation pattern is proportional to the spatial intensity of the recording interference pattern, i.e.,
  • E s ( ⁇ right arrow over (r) ⁇ ) is the spatial distribution of the signal beam field.
  • E s ( ⁇ right arrow over (r) ⁇ )E r *( ⁇ right arrow over (r) ⁇ ) is the signal-bearing (data band) term.
  • FIGS. 1( a ) and 1 ( b ) illustrate example distributions for a Fourier angular-multiplexing geometry.
  • FIG. 1( a ) shows a cross-section of the recording beams E s ( ⁇ right arrow over (k) ⁇ ) 102 and E r ( ⁇ right arrow over (r) ⁇ ) 104 in real space.
  • the cross-hatched region 106 indicates where the beams intersect within the recording layer 108 , and thus where the data-bearing holographic fringes are located.
  • the narrow waist 110 of this region 106 corresponds to the Fourier plane.
  • FIG. 1( b ) illustrates these same distributions in k-space. Since E s ( ⁇ right arrow over (k) ⁇ ) 112 and E r ( ⁇ right arrow over (k) ⁇ ) 114 represent monochromatic optical fields, they may be confined to arcs along the k-sphere. Note that while E r ( ⁇ right arrow over (r) ⁇ ) 104 shows only a single collimated reference beam, the dots in the arc of E r ( ⁇ right arrow over (k) ⁇ ) 114 represent multiple reference beams used to write an angle-multiplexed stack of holograms.
  • E r ( ⁇ right arrow over (k) ⁇ ) 114 may be confined largely to the plane of the figure, E s ( ⁇ right arrow over (k) ⁇ ) 112 may extend out of the figure plane to subtend a page-shaped region (or “patch”) on the surface of the sphere.
  • the data band 116 distribution can be constructed graphically from the cross-correlation of the signal patch E s ( ⁇ right arrow over (k) ⁇ ) 112 with the reference arc E r ( ⁇ right arrow over (k) ⁇ ) 114 .
  • the conjugate data band 118 may be similarly constructed by reversing the order of the operands.
  • the internal structure of the data bands is also indicated.
  • the entire data band (along with the conjugate data band) represents the k-space locus of the holographic fringes for all of the holograms in an angle-multiplexed hologram stack, and each hologram occupies an E s ( ⁇ right arrow over (k) ⁇ ) 112 patch-shaped layer within each of the bands.
  • Each layer has a slight thickness (determined by the Bragg selectivity imparted by the medium thickness) and may be packed in a nested fashion similar to the layers of an onion within the data band to maximize density.
  • FIG. 1( b ) depicts only 14 layers, hundreds or more may be present in an actual implementation.
  • Each hologram/layer may thus occupy a different (substantially disjoint) region of k-space, such that there is little to no cross-talk from other holograms during reconstruction.
  • FIG. 2( a ) illustrates an example holographic data storage system 200 having a monocular architecture.
  • a monocular architecture is a configuration that may employ a very high numerical aperture (NA) objective lens in order to maximize storage density. In this configuration, both the reference and signal beams may pass through the objective lens.
  • NA numerical aperture
  • the example system 200 shown in FIG. 2( a ) is similar to a conventional, off-axis architecture in that it is a page-oriented, angle-multiplexed, Fourier geometry.
  • FIG. 2( b ) illustrates the angular aperture map 210 of system 200 .
  • the x and y locations of angular aperture map 210 indicate the external angle of incidence of beam components into the recording medium.
  • an image of the SLM may coincide with the angular aperture plane.
  • the arrow 216 spanning 50° to 30° and labeled “Ref-beam” shows the locus of the reference beam angular apertures.
  • this locus may be further subdivided into multiple (e.g., 192) finely-spaced points corresponding to the multiple (e.g., 192) reference beam angular apertures (e.g., angle of incidences) used for angle multiplexing.
  • the signal beam angular aperture may remain constant during the recording of the multiple (e.g., 192) holograms, and the locus of the signal beam angular aperture may be disjoint (non-overlapping) with the locus of the reference beam angular aperture.
  • a holographic data storage system having a monocular architecture like that shown in FIG. 2( a )
  • overlapping holographic recordings can be made within a recording medium.
  • the recording medium is being used inefficiently.
  • a data storage system implementing dynamic aperture holographic multiplexing may be used to increase the amount of data that can be stored in a recording medium.
  • dynamic aperture holographic multiplexing involves the changing of the signal beam angle aperture for different holograms in a multiplexed set.
  • FIG. 3( a ) shows an angular aperture map of a data storage system having a monocular architecture that does not implement dynamic aperture holographic multiplexing.
  • the reference beam is confined (e.g., to a scan range of 23° ( ⁇ 58° to ⁇ 35°)), and the edge 304 of the signal beam locus 302 is separated from the reference beam locus 306 (e.g., by a minimum of 15° (worst selectivity case)) according to a representative design criterion.
  • the reference beam locus 306 may be subdivided into multiple (e.g., 192) reference angles, again according to a design rule based on constant minimum Bragg selectivity. According to a software model, this configuration (along with other assumptions) may result in a user capacity of 700 GB on a 120 mm disk.
  • FIG. 3( b ) shows an angular aperture map of a data storage system having a monocular architecture that implements dynamic aperture holographic multiplexing.
  • the reference beam scan range has been expanded to 101° ( ⁇ 58° to +43°).
  • the minimum separation of 15° between reference beam angular apertures of locus 316 and angular apertures of signal beam locus 312 may be achieved by dynamically changing the signal beam angular aperture such that the closest edge of each signal beam angular aperture is selected to be 15° higher than the angular aperture of the reference beam used to record it.
  • the locus 316 of the reference beam angular apertures is thus shared with the locus 312 of the signal beam angular apertures.
  • holograms may be recorded in order of ascending reference beam angular aperture, and thus with a shrinking signal beam angular aperture as the reference beam scans from left to right in the figure. In other examples, the holograms may be recorded in other orders. While specific values (e.g., of minimum separation, reference beam scan range, and signal beam angular aperture) were provided for the example above, it should be appreciated that other values may be used.
  • the signal beam angular aperture may be dynamically changed by changing the subset of the SLM pixels that are included in the holographic data page.
  • regions of the signal angular aperture that are not included in the holographic data page may be darkened to prevent their illuminating the recording medium.
  • this darkening may be accomplished by setting SLM pixels corresponding to the excluded regions to a dark, or “off” state.
  • this darkening may be accomplished using a knife edge shutter or similar device to selectively block illumination from excluded aperture regions while passing illumination from included regions. Such a method might be used if, for example, the SLM employed does not produce an appropriate dark pixel state.
  • this darkening may be accomplished by a beam shaping device that dynamically redirects light from dark regions to illuminated regions.
  • the number of holograms multiplexed may be increased from 192 to 834 using dynamic aperture holographic multiplexing. Because the size of the signal beam angular aperture may decrease as the reference angular aperture moves, the amount of data per hologram may also decrease. Nevertheless, the total amount of data that may be recorded in the recording medium may increase substantially. Applying the same model used for the example shown in FIG. 3( a ), the maximum user capacity may increase from 700 GB to 1.7 TB, which is an improvement of over 240%.
  • FIGS. 4( a ) and 4 ( b ) illustrate example graphs showing relationships between various storage attributes with respect to the multiplexed hologram number when using dynamic aperture holographic multiplexing.
  • the solid line of FIG. 4( a ) indicates the user capacity in TB as a function of the number of multiplexed hologram (pages) according to the model.
  • the dashed line of FIG. 4( a ) shows the average number of recorded pixels per hologram, which is a useful proxy for the transfer rate that may be achieved by a real device.
  • the points indicated by the circle and the x indicate the capacity and transfer rate of a conventional system, respectively.
  • a designer may elect to record only a subset of these holograms in a real system. For example, if 500 holograms were used instead of 834, the device would achieve over 1.5 TB of capacity with a transfer rate penalty of only 17% compared to the conventional system.
  • FIG. 4( b ) shows the angle (solid line) and angular spacing (dashed line) of the reference beams produced by the model.
  • the figure illustrates the increased angular density that may be available in the middle of the scan range to a design employing a constant minimum Bragg selectivity spacing rule.
  • any spacing rule may be employed without departing from the scope of the present disclosure.
  • FIG. 5 illustrates an example holographic data storage system 500 for performing dynamic aperture holographic multiplexing.
  • System 500 generally includes a laser source 502 , a beam directing device (e.g., a galvanometer) 504 for directing the output of the laser source 502 , a polarizing beam splitter (“PBS”) 506 in conjunction with a thin strip half-wave plate (“Strip HWP”) 508 that may collectively act as an aperture sharing element, a detector 522 for performing the recovery operation, an SLM 520 for modulating the signal beam 512 , a polytopic aperture 518 , a high NA objective lens 510 through which both the reference beam 516 and signal beam 512 may pass, and a recording medium 514 . While not shown, SLM 520 may receive an output from laser source 502 and modulate that output to generate the signal beam.
  • System 500 may further include a processor (not shown) for controlling laser source 502 , beam directing device 504 , and SLM 520 .
  • System 500 may include an aperture sharing element to combine the reference 516 and signal beam 512 paths in the regions that are shared between the two.
  • the aperture sharing function may be performed using a passive method utilizing PBS 506 in conjunction with Strip HWP 508 .
  • PBS 506 may serve to combine the beams 512 and 516 in orthogonal polarization states, for example, with the signal beam 512 in the linearly-polarized “s” state (with respect to the PBS 506 hypotenuse), and the reference beam 516 in the “p” state.
  • Strip HWP 508 may be placed in the back focal plane of the objective lens 510 where the reference beam 516 comes to a focus. This plane may also be an image plane of the SLM 520 .
  • Strip HWP 508 may be aligned with the transit path of the reference beam 516 , but may be sufficiently narrow that it occludes only a few rows of SLM pixels. In some examples, the occlusion may be confined to a single row. To account for this occlusion, the occluded SLM pixel(s) may be easily omitted from the SLM page data format with negligible loss of capacity.
  • the birefringent axes of the Strip HWP 508 may be oriented so as to rotate the reference beam polarization to the “s” state, thus allowing the reference beam to interfere with the signal beam and enabling the recording of holographic fringes. The fringes so written are disjoint in k-space.
  • passive aperture sharing may be accomplished using a thin strip mirror that reflects only the reference beam, thus allowing the beams to be combined in the same polarization state.
  • the larger schematic in FIG. 5 shows the assembly with the reference beam 516 near the start of its scan range where the SLM page is large, whereas the inset 524 to the right shows the beam positions near the end of the scan range where the SLM page is small.
  • beam directing device 504 and SLM 520 may be used to adjust the angle of incidence of reference beam 516 and the signal beam angular aperture of signal beam 512 , respectively.
  • an active aperture sharing element employing a switchable element, such as a MEMS-actuated micro-mirror array, to dynamically select the desired beam source for each region of the shared aperture, may be used.
  • a single SLM may be used to generate both signal and reference beams, and may thus itself be considered to be an active aperture sharing element.
  • other architectures potentially employing other methods of either passive or active aperture sharing, may additionally or alternatively be used.
  • FIGS. 6( a ) and 6 ( b ) illustrate the results of a k-space analysis for system 500 using a method similar to that described above with respect to FIGS. 1( a ) and 1 ( b ).
  • FIG. 6( a ) illustrates a cross-section of k-space distributions for a monocular system.
  • FIG. 6( b ) shows the analogous k-space distributions that may result using dynamic aperture holographic multiplexing as described above with respect to FIGS. 3-5 . As is evident in FIG.
  • the layers representing individual holograms within the data band continue to nest in disjoint regions of k-space despite the fact that the loci of E s ( ⁇ right arrow over (k) ⁇ ) and E r ( ⁇ right arrow over (k) ⁇ ) are no longer disjoint over the multiplexed set.
  • the overall volume occupied by the data band and conjugate data band is larger than in that shown in FIG. 6( a ), reflecting the increased multiplexing density of the present disclosure.
  • dynamic aperture equalization may be performed by interleaving data page sizes. For example, the edge of the signal beam angular aperture may be changed every other hologram so that only the odd (or alternatively even) numbered holograms have the lowest allowable frequency components.
  • the angular apertures of the signal beams for odd holograms may be separated from the angular apertures of the reference beams by 15° as described, while the angular apertures of the signal beams for even (or alternatively odd) holograms may instead be separated from the angular apertures of the reference beams by 40°.
  • the resulting k-space distributions are illustrated in FIG.
  • dynamic aperture equalization may be performed with or without shared aperture multiplexing. Additionally, interleaving patterns of different lengths (not just odd/even), and patterns that are not cyclical may also be performed. In general, any technique that equalizes the k-space modulation distribution may be performed and may be referred to as dynamic aperture equalization.
  • Holographic storage devices typically employ error correcting codes in order to achieve robust data recovery in the presence of recovery errors.
  • systematic codes may be used to append parity data to the input data to allow for reconstruction when some part of the whole cannot be recovered.
  • Examples of systematic codes include low density parity check (LDPC) codes and Reed-Solomon codes.
  • the parity portion of the data recorded may be preferentially distributed to some subset of the data pages, while input data may be preferentially distributed to some other subset.
  • parity data may be preferentially distributed to smaller data pages, while input data may be preferentially distributed to larger ones. Distributing the parity data in this way advantageously improves the recovery transfer rate because in the event of error-free recovery of the input data, the parity data residing on the smaller data pages need not be recovered.
  • the parity pages may be selectively distributed to lower data rate (smaller) pages.
  • regions of the aperture may be shared multiple times. Multiple sharing of the signal and/or reference angular apertures can be used to access grating space that is inaccessible to the “singly shared” methods discussed above. Multiple sharing in this context is distinct from the “sharing” of an underlying multiplexing scheme, such as the angle multiplexing described above.
  • multiple locus aperture sharing may include double sharing and may be performed with the dynamic aperture holographic multiplexing described above.
  • FIGS. 8( a ) and 8 ( b ) illustrate one example arrangement for double aperture sharing.
  • FIG. 8( a ) shows an aperture map comparable to the aperture sharing of FIG. 3( b ) with two modifications: 1) the aperture map has been rotated by ⁇ 45°; and 2) a second edge (“Edge 2”) 804 has been added to the signal beam angular aperture locus 802 .
  • This arrangement may then be used to affect aperture sharing in the manner described above, with Edge 1 808 leading the reference beam angular aperture locus 806 by some amount (e.g.,)15°.
  • the new signal edge, Edge 2 804 may be dynamically changed so that its y-component is always slightly less than the y-component of the reference beam. Then, by applying the k-space formalism described above, it is apparent that the k y component of the data band grating distribution so generated will always be less than zero (e.g., the data band lies in the negative k y half of k-space). The conjugate data band, conversely, has a k y component greater than zero.
  • FIG. 8( b ) is similar to FIG. 8( a ), except that the distributions have been flipped about the x-axis.
  • the data band grating distribution for this example will lie entirely in the positive k y half of k-space (and the conjugate band will lie in the negative half).
  • both sets of holograms may be multiplexed into the same volume of recording medium.
  • Such a system may achieve a recording density of somewhat less than double that of the example described with respect to FIGS. 3-5 , with a somewhat decreased average number of pixels per hologram (and, hence, transfer rate).
  • the multiple locus hologram distributions may or may not be symmetric in k-space, and three, four, or even more distributions may be employed.
  • the method may be practiced in combination with multiplexing methods other than angular multiplexing and/or polytopic multiplexing.
  • multiple locus multiplexing may be performed simultaneously, rather than sequentially, by employing substantially orthogonal polarization states for the recording or recovery of two shared apertures simultaneously.
  • the shared apertures of FIGS. 8( a ) and 8 ( b ) may each be recorded or recovered with reference and signal light in the linearly-polarized “s” state with respect to their own reference beams. Since these polarizations are substantially orthogonal to each other, a recording operation may not produce significant interference fringes between reference A and signal B, or between reference B and signal A. Thus the two distributions may be recorded simultaneously.
  • the holographic data storage system may include two separate SLMs and reference scanners, as well as another aperture sharing element based on polarization (such as a PBS) used to combine the beams.
  • the system may further include two detectors to perform the recovery operation, and the new aperture sharing element may direct light of each polarization toward the appropriate detector. Polarization multiplexing would thus achieve a factor of two increase in transfer rate for both recording and recovery compared to the equivalent non-polarization multiplexed system.
  • System 900 generally includes a laser source 902 (e.g., green or blue), an SLM 904 for producing a reference beam and a signal (information) beam, a polarizing beam splitter (PBS) 906 , a dichroic mirror 908 , quarter-wave plate (QWP) 910 , objective lens 912 , recording media 914 , laser source 916 (e.g., red), photo-detector 918 , ring mask 920 , land CMOS or CCD sensor 922 .
  • System 900 may further include a processor (not shown) for controlling laser sources 902 and 916 , SLM 904 , and other components of the system. Additional lenses and/or reflectors may also be included in system 900 , as shown in FIG. 9 .
  • a combined image of the signal beam and the reference beam may be produced by SLM 904 .
  • the loci of the reference and signal components are labeled, showing the annular reference pattern 1002 surrounding a central data page 1004 .
  • the p-polarized output of SLM 904 may pass through PBS 906 and may then be incident on QWP 910 .
  • the p-polarized beams may be converted to a circularly polarized state by QWP 910 and may be focused in the holographic recording media 914 by objective lens 912 .
  • only the outer reference beam may be generated by SLM 904 and passed through PBS 906 , QWP 910 , and objective lens 912 onto holographic recording media 914 .
  • a reconstructed signal beam may be produced and may be reflected back through objective lens 912 and passed through QWP 908 , where it may be converted from a circularly polarized state to an s-polarized state.
  • the reconstructed signal beam may be then reflected by PBS 906 and detected using CMOS or CCD sensor 922 .
  • Laser source 916 may be used for optical servo control to adjust the focal point of the objective lens 912 .
  • a collinear system similar or identical to that shown in FIG. 9 may be modified to benefit from dynamic aperture holographic multiplexing.
  • the modified SLM patterns of FIG. 11 may be generated by shifting the position of the signal beam angular aperture to the edge of the SLM (e.g., in the directions of 0°, 120°, and 240° for FIGS. 11( a ), 11 ( b ), and 11 ( c ), respectively) and modifying the position of the reference beam angular aperture to accommodate these shifts.
  • a threshold angle difference may be maintained between edges of the signal beam angular aperture and the reference beam angular aperture. The threshold angle may be the same or different for each of the modified patterns.
  • the overall volume of the data bands and conjugate data bands of the holograms so multiplexed may be larger than in the conventional case. This may result in a higher theoretical recording density.
  • Collinear holography relies on a correlation effect for holographic multiplexing.
  • individual holograms in collinear recording are broadly distributed and densely overlapped with other holograms, leading to cross-talk expressions such as that of Shima et al.
  • Dynamic aperture holographic multiplexing described herein serves to slightly reduce the overlap of these distributions, and thus serves to slightly reduce cross-talk by driving the design toward a more disjoint k-space partitioning scheme.
  • Other variations of this technique may be implemented under the scope of the present disclosure.
  • FIG. 12 illustrates an exemplary process 1200 that can be used to perform dynamic aperture holographic multiplexing.
  • process 1200 may be performed by a holographic data storage system similar or identical to system 500 or 900 .
  • a system similar to system 500 but modified as described with respect to FIGS. 8( a ) and 8 ( b ), may be used.
  • a first hologram may be recorded to a recording medium using a first signal beam angular aperture and a first reference beam having a first reference beam angular aperture.
  • a reference beam may be generated by a laser source (e.g., laser source 502 ) and directed toward an aperture sharing element, such as a PBS in combination with a thin strip half-wave plate (e.g., PBS 506 and Strip HWP 508 ), by a beam directing device (e.g., galvanometer 504 ).
  • a signal beam may also be generated and modulated to contain data using an SLM (e.g., SLM 520 ).
  • the signal beam may be directed toward the aperture sharing element, where the reference and signal beam paths may be combined in the regions that are shared between the two.
  • the PBS may combine the reference and signal beams in orthogonal polarization states (e.g., signal beam in the linearly-polarized “s” state with respect to the PBS hypotenuse and the reference beam in the “p” state).
  • the thin strip half-wave plate may be positioned in the back focal plane of an objective lens (e.g., objective lens 510 ) where the reference beam comes to a focus. This plane may also be an image plane of the SLM.
  • the output of the thin strip half-wave plate may pass through the objective lens before entering a recording medium (e.g., medium 514 ) to record the first hologram.
  • a recording medium e.g., medium 514
  • reference beam may be generated by a laser source (e.g., laser source 902 ) and directed toward an SLM (e.g., SLM 904 ).
  • the SLM may generate both a reference beam and a signal beam, which may then pass through a PBS (e.g., PBS 906 ) and be incident on a QWP (e.g., QWP 910 ).
  • PBS e.g., PBS 906
  • QWP e.g., QWP 910
  • the QWP may convert the p-polarized reference and signal beams to a circularly polarized state and may be focused in a recording medium (e.g., recording medium 914 ) by an objective lens (e.g., objective lens 912 ) to record the first hologram.
  • a recording medium e.g., recording medium 914
  • an objective lens e.g., objective lens 912
  • the reference beam angular aperture and the edge of the signal beam angular aperture nearest the reference beam angular aperture may be separated by a threshold angle.
  • the separation between the reference beam angular aperture and the signal beam angular aperture may be set by adjusting the orientation of the beam deflecting device (e.g., galvanometer 504 ) reflecting the output of the laser source and/or by causing the SLM to change the size and position at which the signal beam enters the aperture sharing element (e.g., the PBS).
  • the signal beam angular aperture may be dynamically changed by changing the subset of the SLM pixels that are included in the holographic data page.
  • regions of the signal angular aperture that are not included in the holographic data page may be darkened to prevent their illuminating the recording medium.
  • this darkening may be accomplished by setting SLM pixels corresponding to the excluded regions to a dark, or “off” state. In other examples, this darkening may be accomplished using a knife edge shutter or similar device to selectively block illumination from excluded aperture regions while passing illumination from included regions. Such a method might be used if, for example, the SLM employed does not produce an appropriate dark pixel state. In still other examples, this darkening may be accomplished by a beam shaping device that dynamically redirects light from dark regions to illuminated regions. In some examples, the threshold angle separating the angular apertures of the reference and signal beams may be selected such that the edge of the signal beam angular aperture may be 15° higher than the angular aperture of the reference beam used to record it. However, other differences in angles may be used.
  • the separation between the reference beam angular aperture and the signal beam angular aperture may be set by causing the SLM (e.g., SLM 904 ) to shift the signal beam angular aperture to the edge of the SLM (e.g., in the directions of 0°, 120°, or 240° as shown in FIGS. 11( a ), 11 ( b ), and 11 ( c ), respectively) and to shift the reference beam angular aperture to accommodate the shifted signal beam angular aperture.
  • This may be done in a manner that results in a threshold angle separation between the reference beam angular aperture and the edge of the signal beam angular nearest the reference beam angular aperture.
  • a separation of approximately 1, 2, 4, 8, or other number of degrees may be created between the annular reference pattern (e.g., annular reference pattern 1002 ) and the flat edges of the central data page (e.g., central data page 1004 ) and a separation of less than 1, 2, 4, or other number of degrees may be created between the annular reference pattern and the corners of central data page.
  • a second hologram may be recorded to the recording medium using a second signal beam angular aperture and a second reference beam having a second reference beam angular aperture.
  • the second reference beam may be similar to the first reference beam used to record the first hologram at block 1202 , except that a characteristic of the first reference beam may be modified to generate the second reference beam at block 1204 .
  • the second signal beam angular aperture may be similar to the first signal beam angular aperture used to record the first hologram at block 1202 , except that a characteristic of the first signal beam angular aperture may be modified to generate the second signal beam angular aperture at block 1204 .
  • the reference beam may be modified so as to change its angular aperture (e.g., angle of incidence with respect to the recording medium). This may be performed by, for example, adjusting the orientation of the beam directing device reflecting the output of the laser source.
  • the signal beam angular aperture may be modified such that the reference beam angular aperture and the edge of the signal beam angular aperture nearest the reference beam angular aperture may be separated by a threshold angle. This may be accomplished by causing the SLM to change the size and position at which the signal beam enters the aperture sharing element, as described above.
  • the threshold angle may be the same or substantially the same (e.g., within a tolerance threshold) as the threshold angle used at block 1202 (e.g., the edge of the signal beam angular aperture may be 15° higher than the angular aperture of the reference beam used to record it).
  • the signal beam angular aperture may be modified by the same or substantially the same (e.g., within a tolerance threshold) amount as the angular aperture of the reference beam used to record it.
  • the threshold angle may be different than the threshold angle used at block 1202 .
  • the threshold angle may be selected such that the edge of the signal beam angular aperture may be 40° higher than the angular aperture of the reference beam used to record it. However, other differences in angles may be used.
  • the SLM may shift the signal beam angular aperture to a different edge of the SLM (e.g., in the directions of 0°, 120°, or 240° as shown in FIGS. 11( a ), 11 ( b ), and 11 ( c ), respectively, or other direction) and may shift the reference beam angular aperture to accommodate the shifted signal beam angular aperture. This may be done in a manner that results in a threshold angle separation between the reference beam angular aperture and the edge of the signal beam angular aperture nearest the reference beam angular aperture.
  • the threshold angle may be the same as or different than the threshold angle used at block 1202 .
  • a third hologram may be recorded to the recording medium using a third signal beam angular aperture and a third reference beam having a third angular aperture.
  • the third reference beam may be similar to the first reference beam used to record the first hologram at block 1202 , except that a characteristic of the first reference beam may be modified to generate the third reference beam at block 1206 .
  • the third signal beam angular aperture may be similar to the first signal beam angular aperture used to record the first hologram at block 1202 , except that a characteristic of the first signal beam angular aperture may be modified to generate the third signal beam angular aperture at block 1206 .
  • block 1206 may be performed in a manner similar to that of block 1204 , except that the reference beam angular aperture may be different than that used in any of the previous recordings (e.g., first and second recordings made at blocks 1202 and 1204 ) and that the signal beam angular aperture may be modified such that the reference beam angular aperture and the edge of the signal beam angular aperture nearest the reference beam angular aperture may be separated by a threshold angle.
  • the threshold angles used at blocks 1202 and 1204 were the same (or at least substantially the same)
  • the threshold angle used at block 1206 may also be the same (e.g., 15 degrees) or substantially the same.
  • the threshold angle used at block 1206 may be the same (or at least substantially the same) as that used at block 1202 (e.g., 15 degrees). In this way, dynamic aperture equalization may be achieved by interleaving data page sizes to reduce cross-talk between holograms.
  • block 1206 may be performed in a manner similar to that of block 1204 , except that the reference beam angular aperture may be different than that used in any of the previous recordings (e.g., first and second recordings made at blocks 1202 and 1204 ) and that the signal beam angular aperture may be modified such that the reference beam angular aperture and the edge of the signal beam angular aperture nearest the reference beam angular aperture may be separated by a threshold angle.
  • the threshold angles used at blocks 1202 and 1204 were the same (or at least substantially the same), the threshold angle used at block 1206 may also be the same or substantially the same.
  • the threshold angle used at block 1206 may be the same (or at least substantially the same) as that used at block 1202 . In this way, dynamic aperture equalization may be achieved by interleaving data page sizes to reduce cross-talk between holograms.
  • a fourth hologram may be recorded to the recording medium using a fourth signal beam angular aperture and a fourth reference beam having a fourth angular aperture.
  • the fourth reference beam may be similar to the first reference beam used to record the first hologram at block 1202 , except that a characteristic of the first reference beam may be modified to generate the fourth reference beam at block 1208 .
  • the fourth signal beam angular aperture may be similar to the first signal beam angular aperture used to record the first hologram at block 1202 , except that a characteristic of the first signal beam angular aperture may be modified to generate the fourth signal beam angular aperture at block 1208 .
  • block 1208 may be performed in a manner similar to that of block 1204 , except that the reference beam angular aperture may be different than that used in any of the previous recordings (e.g., first, second, and third recordings made at blocks 1202 , 1204 , and 1206 ) and that the signal beam angular aperture may be modified such that the reference beam angular aperture and the edge of the signal beam angular aperture nearest the reference beam angular aperture may be separated by a threshold angle.
  • the reference beam angular aperture may be different than that used in any of the previous recordings (e.g., first, second, and third recordings made at blocks 1202 , 1204 , and 1206 ) and that the signal beam angular aperture may be modified such that the reference beam angular aperture and the edge of the signal beam angular aperture nearest the reference beam angular aperture may be separated by a threshold angle.
  • the threshold angle used at block 1208 may also be the same (e.g., 15 degrees) or substantially the same. In other examples where at least some of the threshold angles used at blocks 1202 , 1204 , and 1206 were different, the threshold angle used at block 1208 may be the same or substantially the same as that used at block 1204 (e.g., 40 degrees). In these examples, the threshold angles for the first and third holograms may be the same or substantially the same, while the threshold angles for the second and fourth holograms may be the same or substantially the same. However, the threshold angle for the first and third holograms may be different than the threshold angle for the second and fourth holograms. In this way, dynamic aperture equalization may be achieved by interleaving data page sizes to reduce cross-talk between holograms.
  • block 1208 may be performed in a manner similar to that of block 1204 , except that the reference beam angular aperture may be different than that used in any of the previous recordings (e.g., first, second, and third recordings made at blocks 1202 , 1204 , and 1206 ) and that the signal beam angular aperture may be modified such that the reference beam angular aperture and the edge of the signal beam angular aperture nearest the reference beam angular aperture may be separated by a threshold angle.
  • the threshold angles used at blocks 1202 , 1204 , and 1206 were the same (or at least substantially the same)
  • the threshold angle used at block 1208 may also be the same or substantially the same.
  • the threshold angle used at block 1208 may be the same or substantially the same as that used at block 1204 .
  • the threshold angles for the first and third holograms may be the same or substantially the same, while the threshold angles for the second and fourth holograms may be the same or substantially the same.
  • the threshold angle for the first and third holograms may be different than the threshold angle for the second and fourth holograms. In this way, dynamic aperture equalization may be achieved by interleaving data page sizes to reduce cross-talk between holograms.
  • additional holograms may be recorded in a manner similar to that described with respect to blocks 1204 , 1206 , and 1208 .
  • Each additional hologram may be recorded using a reference beam that is different than any of those previously used to record holograms and a signal beam that has been dynamically adjusted accordingly, as described above.
  • the threshold angle offset between the reference beam angular aperture and the edge of the signal beam angular aperture nearest the reference beam may be the same or substantially the same as the threshold angles used in each of the previous recordings.
  • the threshold angle offset may be interleaved such that even numbered holograms may use the same or substantially the same threshold angle and odd numbered holograms may use the same or substantially the same threshold angle (different from the angle used for the even numbered holograms) in order to perform dynamic aperture equalization to reduce cross-talk between holograms.
  • other non-uniform distributions of threshold angles may be used to generate the holograms.
  • process 1200 may include the use of error correcting codes.
  • some of the data pages or holograms may be used to store parity information, while the other data pages are used to store input data.
  • the smaller data pages may be used to store the parity information, while the remaining data pages may be used to store input data. This may advantageously improve the recovery transfer rate because in the event of error-free recovery of the input data, the parity data residing on the smaller data pages need not be recovered.
  • process 1200 may include multiple locus aperture sharing, as discussed above. In these examples, regions of the aperture may be shared multiple times. For example, process 1200 may include double sharing, as described above with respect to FIGS. 8( a ) and 8 ( b ).
  • multiple locus multiplexing may be performed simultaneously, rather than sequentially, by employing substantially orthogonal polarization states for the recording or recovery of two shared apertures simultaneously.
  • the shared apertures of FIGS. 8( a ) and 8 ( b ) may each be recorded or recovered with reference and signal light in the linearly-polarized “s” state with respect to their own reference beams. Since these polarizations are substantially orthogonal to each other, a recording operation may not produce significant interference fringes between reference A and signal B, or between reference B and signal A. Thus the two distributions may be recorded simultaneously.
  • the holographic data storage system may instead include two separate SLMs and reference scanners, as well as another aperture sharing element based on polarization (such as a PBS) used to combine the beams.
  • the system may further include two detectors to perform the recovery operation, and the new aperture sharing element may direct light of each polarization toward the appropriate detector.
  • FIG. 13 depicts computing system 1300 with a number of components that may be used to perform the above-described processes.
  • the main system 1302 includes a motherboard 1304 having an input/output (“I/O”) section 1306 , one or more central processing units (“CPU”) 1308 , and a memory section 1310 , which may have a flash memory card 1312 related to it.
  • the I/O section 1306 is connected to a display 1324 , a keyboard 1314 , a disk storage unit 1316 , and a media drive unit 1318 .
  • the media drive unit 1318 can read/write a non-transitory computer-readable storage medium 1320 , which can contain programs 1322 and/or data.
  • a non-transitory computer-readable medium can be used to store (e.g., tangibly embody) one or more computer programs for performing any one of the above-described processes by means of a computer.
  • the computer program may be written, for example, in a general-purpose programming language (e.g., Pascal, C, C++, Java) or some specialized application-specific language.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Optical Recording Or Reproduction (AREA)
  • Holo Graphy (AREA)
  • Optical Head (AREA)
US13/875,071 2013-01-23 2013-05-01 Dynamic aperture holographic multiplexing Abandoned US20140204437A1 (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
US13/875,071 US20140204437A1 (en) 2013-01-23 2013-05-01 Dynamic aperture holographic multiplexing
US14/385,469 US9760061B2 (en) 2013-01-23 2014-03-21 Dynamic aperture holography
JP2015554300A JP2016510931A (ja) 2013-01-23 2014-03-21 ダイナミックアパーチャホログラフィ
EP14743821.2A EP2948948A4 (en) 2013-01-23 2014-03-21 HOLOGRAPHY OF DYNAMIC OPENING
PCT/IB2014/060014 WO2014115129A2 (en) 2013-01-23 2014-03-21 Dynamic aperture holography
KR1020147031165A KR101526836B1 (ko) 2013-01-23 2014-03-21 동적 개구 홀로그래피

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US201361755893P 2013-01-23 2013-01-23
US13/875,071 US20140204437A1 (en) 2013-01-23 2013-05-01 Dynamic aperture holographic multiplexing

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US14/385,469 Continuation US9760061B2 (en) 2013-01-23 2014-03-21 Dynamic aperture holography

Publications (1)

Publication Number Publication Date
US20140204437A1 true US20140204437A1 (en) 2014-07-24

Family

ID=51207473

Family Applications (2)

Application Number Title Priority Date Filing Date
US13/875,071 Abandoned US20140204437A1 (en) 2013-01-23 2013-05-01 Dynamic aperture holographic multiplexing
US14/385,469 Expired - Fee Related US9760061B2 (en) 2013-01-23 2014-03-21 Dynamic aperture holography

Family Applications After (1)

Application Number Title Priority Date Filing Date
US14/385,469 Expired - Fee Related US9760061B2 (en) 2013-01-23 2014-03-21 Dynamic aperture holography

Country Status (5)

Country Link
US (2) US20140204437A1 (https=)
EP (1) EP2948948A4 (https=)
JP (1) JP2016510931A (https=)
KR (1) KR101526836B1 (https=)
WO (1) WO2014115129A2 (https=)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9640215B2 (en) 2015-05-19 2017-05-02 National Central University Holographic light-emitting module and holographic storage system using the same
US10181336B1 (en) * 2017-08-08 2019-01-15 Microsoft Technology Licensing, Llc Multi-beam optical system for fast writing of data on glass
US10236027B1 (en) 2018-02-12 2019-03-19 Microsoft Technology Licensing, Llc Data storage using light of spatially modulated phase and polarization
US10248081B2 (en) 2017-03-10 2019-04-02 Microsoft Technology Licensing, Llc Holographic phase and amplitude spatial light modulation
CN111243628A (zh) * 2019-12-31 2020-06-05 广东紫晶信息存储技术股份有限公司 一种双面同时记录/读取的全息存储装置及方法
US10809529B2 (en) 2017-06-15 2020-10-20 Microsoft Technology Licensing, Llc Optical device having multiplexed electrodes
CN114690305A (zh) * 2017-10-04 2022-07-01 阿科尼亚全息有限责任公司 梳状移位式斜交镜
US20220262398A1 (en) * 2019-10-30 2022-08-18 Huawei Technologies Co., Ltd. Detection Apparatus, Optical Drive, and Detection Method
US20230296968A1 (en) * 2020-08-30 2023-09-21 Lumus Ltd. Reflective slm image projector with intermediate image plane

Families Citing this family (55)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB0522968D0 (en) 2005-11-11 2005-12-21 Popovich Milan M Holographic illumination device
GB0718706D0 (en) 2007-09-25 2007-11-07 Creative Physics Ltd Method and apparatus for reducing laser speckle
US11726332B2 (en) 2009-04-27 2023-08-15 Digilens Inc. Diffractive projection apparatus
US9335604B2 (en) 2013-12-11 2016-05-10 Milan Momcilo Popovich Holographic waveguide display
WO2012136970A1 (en) 2011-04-07 2012-10-11 Milan Momcilo Popovich Laser despeckler based on angular diversity
EP2748670B1 (en) 2011-08-24 2015-11-18 Rockwell Collins, Inc. Wearable data display
WO2016020630A2 (en) 2014-08-08 2016-02-11 Milan Momcilo Popovich Waveguide laser illuminator incorporating a despeckler
US10670876B2 (en) 2011-08-24 2020-06-02 Digilens Inc. Waveguide laser illuminator incorporating a despeckler
WO2013102759A2 (en) 2012-01-06 2013-07-11 Milan Momcilo Popovich Contact image sensor using switchable bragg gratings
CN103562802B (zh) 2012-04-25 2016-08-17 罗克韦尔柯林斯公司 全息广角显示器
US9456744B2 (en) 2012-05-11 2016-10-04 Digilens, Inc. Apparatus for eye tracking
US9933684B2 (en) * 2012-11-16 2018-04-03 Rockwell Collins, Inc. Transparent waveguide display providing upper and lower fields of view having a specific light output aperture configuration
WO2014188149A1 (en) 2013-05-20 2014-11-27 Milan Momcilo Popovich Holographic waveguide eye tracker
WO2015015138A1 (en) 2013-07-31 2015-02-05 Milan Momcilo Popovich Method and apparatus for contact image sensing
WO2016020632A1 (en) 2014-08-08 2016-02-11 Milan Momcilo Popovich Method for holographic mastering and replication
US10241330B2 (en) 2014-09-19 2019-03-26 Digilens, Inc. Method and apparatus for generating input images for holographic waveguide displays
WO2016046514A1 (en) 2014-09-26 2016-03-31 LOKOVIC, Kimberly, Sun Holographic waveguide opticaltracker
EP3245551B1 (en) 2015-01-12 2019-09-18 DigiLens Inc. Waveguide light field displays
WO2016113534A1 (en) 2015-01-12 2016-07-21 Milan Momcilo Popovich Environmentally isolated waveguide display
WO2016116733A1 (en) 2015-01-20 2016-07-28 Milan Momcilo Popovich Holographic waveguide lidar
TWI571869B (zh) * 2015-01-30 2017-02-21 國立中央大學 全像裝置與其資料讀取方法
JP6138982B2 (ja) 2015-01-30 2017-05-31 國立中央大學 ホログラフィック装置及びそのデータの読み取り方法
US9542970B2 (en) * 2015-01-30 2017-01-10 National Central University Light interference module and holographic storage apparatus
US9632226B2 (en) 2015-02-12 2017-04-25 Digilens Inc. Waveguide grating device
US10459145B2 (en) 2015-03-16 2019-10-29 Digilens Inc. Waveguide device incorporating a light pipe
US10591756B2 (en) 2015-03-31 2020-03-17 Digilens Inc. Method and apparatus for contact image sensing
CN113759555B (zh) 2015-10-05 2024-09-20 迪吉伦斯公司 波导显示器
US10983340B2 (en) 2016-02-04 2021-04-20 Digilens Inc. Holographic waveguide optical tracker
SG10201901665XA (en) 2016-03-22 2019-03-28 Lyteloop Technologies Llc Data in motion storage system and method
CN108780224B (zh) 2016-03-24 2021-08-03 迪吉伦斯公司 用于提供偏振选择性全息波导装置的方法和设备
JP6734933B2 (ja) 2016-04-11 2020-08-05 ディジレンズ インコーポレイテッド 構造化光投影のためのホログラフィック導波管装置
US11513350B2 (en) 2016-12-02 2022-11-29 Digilens Inc. Waveguide device with uniform output illumination
WO2018129398A1 (en) 2017-01-05 2018-07-12 Digilens, Inc. Wearable heads up displays
EP3698214A4 (en) 2017-10-16 2021-10-27 Digilens Inc. SYSTEMS AND METHODS FOR MULTIPLICATION OF THE IMAGE RESOLUTION OF A PIXELIZED DISPLAY
CN114721242B (zh) 2018-01-08 2025-08-15 迪吉伦斯公司 用于制造光学波导的方法
US10914950B2 (en) 2018-01-08 2021-02-09 Digilens Inc. Waveguide architectures and related methods of manufacturing
CN111566571B (zh) 2018-01-08 2022-05-13 迪吉伦斯公司 波导单元格中全息光栅高吞吐量记录的系统和方法
WO2019135837A1 (en) 2018-01-08 2019-07-11 Digilens, Inc. Systems and methods for manufacturing waveguide cells
EP4372451A3 (en) 2018-03-16 2024-08-14 Digilens Inc. Holographic waveguides incorporating birefringence control and methods for their fabrication
WO2019209095A2 (ko) * 2018-04-22 2019-10-31 Lee Jeong Yong 전자파 홀로그램을 이용한 동력발생장치
US11402801B2 (en) 2018-07-25 2022-08-02 Digilens Inc. Systems and methods for fabricating a multilayer optical structure
CA3101811A1 (en) 2018-08-02 2020-02-06 Lyteloop Technologies, Llc Apparatus and method for storing wave signals in a cavity
KR102315760B1 (ko) 2018-08-10 2021-10-20 라이트루프 테크놀로지스, 엘엘씨 각도 멀티플렉싱을 사용하여 파 신호의 경로 길이를 연장하기 위한 시스템 및 방법
CN112913091A (zh) 2018-11-05 2021-06-04 利特洛普技术有限公司 使用共享的公共组件构建、操作和控制多个放大器、再生器、以及收发器的系统和方法
WO2020149956A1 (en) 2019-01-14 2020-07-23 Digilens Inc. Holographic waveguide display with light control layer
US20200247017A1 (en) 2019-02-05 2020-08-06 Digilens Inc. Methods for Compensating for Optical Surface Nonuniformity
KR102866596B1 (ko) 2019-02-15 2025-09-29 디지렌즈 인코포레이티드. 일체형 격자를 이용하여 홀로그래픽 도파관 디스플레이를 제공하기 위한 방법 및 장치
US20220283377A1 (en) 2019-02-15 2022-09-08 Digilens Inc. Wide Angle Waveguide Display
WO2020186113A1 (en) 2019-03-12 2020-09-17 Digilens Inc. Holographic waveguide backlight and related methods of manufacturing
KR20220016990A (ko) 2019-06-07 2022-02-10 디지렌즈 인코포레이티드. 투과 및 반사 격자를 통합하는 도파관 및 관련 제조 방법
US11681143B2 (en) 2019-07-29 2023-06-20 Digilens Inc. Methods and apparatus for multiplying the image resolution and field-of-view of a pixelated display
WO2021041949A1 (en) 2019-08-29 2021-03-04 Digilens Inc. Evacuating bragg gratings and methods of manufacturing
KR20230119015A (ko) 2020-12-21 2023-08-14 디지렌즈 인코포레이티드. 도파로 기반 디스플레이에서의 홍목현상 억제 기술
US12399326B2 (en) 2021-01-07 2025-08-26 Digilens Inc. Grating structures for color waveguides
KR20230153459A (ko) 2021-03-05 2023-11-06 디지렌즈 인코포레이티드. 진공 주기적 구조체 및 제조 방법

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20070081211A1 (en) * 2005-10-06 2007-04-12 Sony Corporation Hologram recording medium, hologram reproducing apparatus, hologram reproducing method, and hologram sheet
US20080100890A1 (en) * 2006-11-01 2008-05-01 Inphase Technologies Monocular holographic data storage system architecture
US20080309998A1 (en) * 2007-06-13 2008-12-18 Sharp Kabushiki Kaisha Hologram element deflecting optical beam, hologram element fabricating apparatus, hologram element fabricating method, deflection optical unit, and information recording apparatus and information reconstructing apparatus using deflection optical unit

Family Cites Families (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2051193C (en) * 1990-09-14 1995-09-26 Hidetoshi Tatemichi Information recording apparatus
JP3031500B2 (ja) * 1990-09-14 2000-04-10 日本電信電話株式会社 情報記録装置
US5483365A (en) 1994-05-10 1996-01-09 California Institute Of Technology Method for holographic storage using peristrophic multiplexing
US7704643B2 (en) * 2005-02-28 2010-04-27 Inphase Technologies, Inc. Holographic recording medium with control of photopolymerization and dark reactions
JP2006276373A (ja) * 2005-03-29 2006-10-12 Sony Corp ホログラム記録装置及び位相マスク
US7911919B2 (en) * 2006-03-20 2011-03-22 Panasonic Corporation Information recording/reproducing device and hologram recording/reproducing method
US7990830B2 (en) * 2007-03-09 2011-08-02 Hitachi, Ltd. Optical pickup, optical information recording apparatus and optical information recording and reproducing apparatus using the optical pickup
KR20080087312A (ko) * 2007-03-26 2008-10-01 삼성전자주식회사 홀로그래픽 저장 매체, 기록 재생 장치 및 기록 재생 방법
JP5006397B2 (ja) * 2007-06-11 2012-08-22 パイオニア株式会社 ホログラム装置並びにその記録及び再生方法
KR101397434B1 (ko) * 2007-06-21 2014-05-20 삼성전자주식회사 가변 크기의 조리개를 채용한 홀로그래픽 기록/재생 장치
EP2048660A1 (en) * 2007-10-11 2009-04-15 Deutsche Thomson OHG Lens system for common aperture holographic storage system
US8330673B2 (en) * 2009-04-02 2012-12-11 GM Global Technology Operations LLC Scan loop optimization of vector projection display

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20070081211A1 (en) * 2005-10-06 2007-04-12 Sony Corporation Hologram recording medium, hologram reproducing apparatus, hologram reproducing method, and hologram sheet
US20080100890A1 (en) * 2006-11-01 2008-05-01 Inphase Technologies Monocular holographic data storage system architecture
US20080309998A1 (en) * 2007-06-13 2008-12-18 Sharp Kabushiki Kaisha Hologram element deflecting optical beam, hologram element fabricating apparatus, hologram element fabricating method, deflection optical unit, and information recording apparatus and information reconstructing apparatus using deflection optical unit

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
TWI584278B (zh) * 2015-05-19 2017-05-21 國立中央大學 全像光發射模組與應用其的全像儲存系統
US9640215B2 (en) 2015-05-19 2017-05-02 National Central University Holographic light-emitting module and holographic storage system using the same
US10248081B2 (en) 2017-03-10 2019-04-02 Microsoft Technology Licensing, Llc Holographic phase and amplitude spatial light modulation
US10809529B2 (en) 2017-06-15 2020-10-20 Microsoft Technology Licensing, Llc Optical device having multiplexed electrodes
US10181336B1 (en) * 2017-08-08 2019-01-15 Microsoft Technology Licensing, Llc Multi-beam optical system for fast writing of data on glass
CN114690305A (zh) * 2017-10-04 2022-07-01 阿科尼亚全息有限责任公司 梳状移位式斜交镜
US10236027B1 (en) 2018-02-12 2019-03-19 Microsoft Technology Licensing, Llc Data storage using light of spatially modulated phase and polarization
US20220262398A1 (en) * 2019-10-30 2022-08-18 Huawei Technologies Co., Ltd. Detection Apparatus, Optical Drive, and Detection Method
US11887624B2 (en) * 2019-10-30 2024-01-30 Huawei Technologies Co., Ltd. Detection apparatus, optical drive, and detection method
EP3846169A1 (en) * 2019-12-31 2021-07-07 Amethystum Storage Technology Co., Ltd. Holographic storage device and method for simultaneously recording and reading on two sides
CN111243628A (zh) * 2019-12-31 2020-06-05 广东紫晶信息存储技术股份有限公司 一种双面同时记录/读取的全息存储装置及方法
US20230296968A1 (en) * 2020-08-30 2023-09-21 Lumus Ltd. Reflective slm image projector with intermediate image plane
US12535723B2 (en) * 2020-08-30 2026-01-27 Lumus Ltd. Reflective SLM image projector with intermediate image plane

Also Published As

Publication number Publication date
EP2948948A2 (en) 2015-12-02
JP2016510931A (ja) 2016-04-11
KR101526836B1 (ko) 2015-06-05
EP2948948A4 (en) 2016-08-03
WO2014115129A3 (en) 2014-10-09
KR20140142367A (ko) 2014-12-11
US9760061B2 (en) 2017-09-12
WO2014115129A2 (en) 2014-07-31
US20150062675A1 (en) 2015-03-05

Similar Documents

Publication Publication Date Title
US20140204437A1 (en) Dynamic aperture holographic multiplexing
US7742209B2 (en) Monocular holographic data storage system architecture
JP2007508651A5 (https=)
US11169485B2 (en) Hologram displaying apparatus and method thereof
JP2007508651A (ja) 位相変調均質化フーリエ変換ホログラフィック・データ記録および再生の方法および装置
JP2008191330A (ja) 情報記録再生装置
JP2005134762A (ja) 多層ホログラフィック記録媒体、その製造方法、多層ホログラフィック記録再生方法、多層ホログラフィックメモリ再生装置及び多層ホログラフィック記録再生装置
US7180844B2 (en) Holographic disc recording system
JP2010507183A (ja) ホログラフィック記憶アレンジメントにデータを記憶する及びそれからデータを読み出すためのセットアップ及び方法
US8179579B2 (en) HROM replication methods, devices or systems, articles used in same and articles generated by same
JP2008269771A (ja) ホログラフィック記憶媒体からの読出しおよび／またはホログラフィック記憶媒体への書込みを行うための装置
US7995257B2 (en) Holographic storage medium, recording and/or reproducing apparatus, and recording and/or reproducing method
JP4605007B2 (ja) ホログラム記録再生方法及び装置
US7161723B1 (en) Scheme capable of providing gain and thresholding to the parallel recording and replication of holographic media
EP2390731B1 (en) Monocular holographic data storage system architecture
KR102768060B1 (ko) 홀로그램 디스플레이 장치 및 그 방법
CN1954370A (zh) 全息图母片制作和复制
KR20070015220A (ko) 홀로그래픽 데이터를 기록 및 재생하는 광학장치
JP2015164085A (ja) 光情報記録再生装置、光情報記録再生装置に用いる位相マスク及び光情報の記録再生方法
JP4634122B2 (ja) ホログラフィック光メモリ記録装置及び記録再生装置
Yatagai et al. Optical mass-storage based on vector wave holography
JP5298267B2 (ja) 光情報再生装置及び再生方法
Yatagai et al. Polarization holography for optical mass-storage
Matoba et al. Improvement on recording density in reflection-type holographic memory with random phase shift multiplexing

Legal Events

Date Code Title Description
AS Assignment

Owner name: AKONIA HOLOGRAPHICS LLC, COLORADO

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:AYRES, MARK R.;ANDERSON, KENNETH E.;ASKHAM, FREDRIC R.;AND OTHERS;REEL/FRAME:030330/0450

Effective date: 20130501

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION