EP1166188A1 - Materiau d'enregistrement holographique - Google Patents

Materiau d'enregistrement holographique

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Publication number
EP1166188A1
EP1166188A1 EP00912500A EP00912500A EP1166188A1 EP 1166188 A1 EP1166188 A1 EP 1166188A1 EP 00912500 A EP00912500 A EP 00912500A EP 00912500 A EP00912500 A EP 00912500A EP 1166188 A1 EP1166188 A1 EP 1166188A1
Authority
EP
European Patent Office
Prior art keywords
recording material
particularly preferably
material according
alkyl
dye
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.)
Withdrawn
Application number
EP00912500A
Other languages
German (de)
English (en)
Inventor
Horst Berneth
Thomas Bieringer
Johannes Eickmans
Rainer Hagen
Serguei Kostromine
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.)
Bayer AG
Original Assignee
Bayer AG
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 Bayer AG filed Critical Bayer AG
Publication of EP1166188A1 publication Critical patent/EP1166188A1/fr
Withdrawn legal-status Critical Current

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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
    • G03H1/02—Details of features involved during the holographic process; Replication of holograms without interference recording
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F246/00—Copolymers in which the nature of only the monomers in minority is defined
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09B—ORGANIC DYES OR CLOSELY-RELATED COMPOUNDS FOR PRODUCING DYES, e.g. PIGMENTS; MORDANTS; LAKES
    • C09B69/00—Dyes not provided for by a single group of this subclass
    • C09B69/10—Polymeric dyes; Reaction products of dyes with monomers or with macromolecular compounds
    • C09B69/106—Polymeric dyes; Reaction products of dyes with monomers or with macromolecular compounds containing an azo dye
    • 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
    • G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
    • G11B7/241—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
    • G11B7/242—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers
    • G11B7/244—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers comprising organic materials only
    • G11B7/245—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers comprising organic materials only containing a polymeric component
    • 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
    • G03H2001/026—Recording materials or recording processes
    • 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
    • G03H2001/026—Recording materials or recording processes
    • G03H2001/0264—Organic recording material
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H2240/00—Hologram nature or properties
    • G03H2240/20—Details of physical variations exhibited in the hologram
    • G03H2240/26—Structural variations, e.g. structure variations due to photoanchoring or conformation variations due to photo-isomerisation
    • 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
    • G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
    • G11B7/26—Apparatus or processes specially adapted for the manufacture of record carriers

Definitions

  • the present invention relates to a recording material for a holographic volume memory, its production and use for the recording of volume holograms.
  • Holography is a process in which objects can be imaged in suitable storage materials by the interference of two coherent light beams (signal wave and reference wave) and these images can be read out again with light (reading beam) (D. Gabor, Nature 151, 454 (1948), NH Farath, Advances in
  • the light source is usually the light of a laser.
  • Various materials are described as storage material, e.g. B. inorganic crystals such as LiNb0 3 (z. B.), organic polymers (z. BM Eich, JH Wendorff, Makromol. Chem., Rapid Commun. 8, 467 (1987), JH Wendorff, M. Eich, Mol. Cryst Liq. Cryst. 169, 133 (1989)) or photopolymers (Uh-Sock Rhee et al., Applied Optics, 34 (5), 846
  • Holograms addressed the same molecules that contributed to the construction of previously written holograms, so that the information from earlier holograms was lost after only a few more writing processes.
  • the invention accordingly relates to a recording material for a holographic volume memory, containing at least one dye which changes its spatial arrangement when a hologram is written in, and optionally at least one shape-anisotropic grouping, characterized in that it allows two or more holograms to be recorded at a sample position.
  • the at least one dye changes its spatial arrangement so that it can no longer be excited by the electromagnetic radiation or changes its absorption behavior, in particular reduces its sensitivity to actinic light, preferably between 10% and
  • the dye can also reduce its absorption behavior, in particular its sensitivity to actinic light, by folding it in the direction perpendicular to the polarization direction of the actinic light and its longitudinal molecular axis making an angle between 10 ° and 90 °, preferably between, with the polarization direction of the actinic light 50 ° and 90 ° is particularly preferably between 75 ° and 90 ° and very particularly preferably between 85 ° and 90 °.
  • This change in the excitation behavior with regard to electromagnetic radiation when writing in the hologram can be achieved in that the dye changes its spatial arrangement in the polymeric or oligomeric organic, amorphous material.
  • Materials of this type can be used to prevent the holograms previously written into this material from being unacceptably reduced, completely damaged or even completely overwritten when a hologram is written.
  • an unacceptable weakening means that the remaining information can no longer be resolved in relation to the background noise.
  • the information is stored holographically.
  • two polarized, coherent beams are brought to interference on the sample.
  • the dyes change their spatial position in the polymeric or oligomeric layers. Dyes that align their molecular longitudinal axis in the plane that are spanned by the two writing beams (plane of incidence) during exposure are from this
  • the direction of polarization forming an angle ⁇ not equal to 90 ° is addressed further in the case of further hologram exposures.
  • the likelihood of a reorientation of these dyes and in particular the sensitivity of the dyes to light decreases the closer the angle of the molecule's longitudinal axis comes to the 90 ° position.
  • the molecular longitudinal axis can be determined, for example, on the basis of the molecular shape by molecular modeling (eg CERIUS 2 ).
  • the reorientation of the dyes after exposure to actinic light results, for example, from investigations into polarized absorption spectroscopy: A sample previously exposed to actinic light is placed between 2 polarizers in a UV / VIS spectrometer (e.g. CARY 4G, UV / VIS spectrometer) examined in the spectral range of absorption of the dyes.
  • a UV / VIS spectrometer e.g. CARY 4G, UV / VIS spectrometer
  • the reorientation of the dyes follows from the intensity profile of the extinction as a function of the sample angle and can thus be clearly determined.
  • a measure of the sensitivity to actinic light is holographic
  • the sensitivity is defined as the slope of the root of the diffraction efficiency according to the deposited energy, normalized to the thickness of the storage medium.
  • the invention relates to a recording material for a holographic volume memory that has an optical density ⁇ 2, preferably ⁇ 1, particularly preferably ⁇ 0.3 at the wavelength of the writing laser. In this way it can be ensured that the actinic light leads to homogeneous illumination of the entire storage medium and a thick hologram can be generated.
  • the optical density can be determined with commercial UV / VIS spectrometers (e.g. company CARY 4G, UV - VIS spectrometer).
  • the recording material according to the invention is a material which has an irradiated thickness of> 0.1 mm, particularly 0.5 mm, preferably> 1 mm and very particularly preferably not greater than 5 cm.
  • the grouping that interacts with the electromagnetic radiation is a dye.
  • the material according to the invention consequently contains at least one dye.
  • the electromagnetic radiation is preferably laser light, preferably in the wavelength range between 390 to 800 nm, particularly preferably in the range 400 to 650 nm, very particularly preferably in the range from 510 to 570 nm.
  • the recording material is no longer exposed to two interfering beams as in writing, but only one beam, the reading beam.
  • the wavelength of the reading beam is preferably longer than that of the signal and reference waves, for example 70 to 500 nm longer.
  • reading with the wavelength of the writing laser is also possible and will be used in particular in the commercial use of holographic volume memories.
  • the energy of the reading beam is reduced during the reading process either by reducing the exposure intensity or the exposure time, or by reducing the exposure intensity and the exposure time.
  • optical density of the recording material according to the invention is set by the following two parameters
  • Dyes with low extinction coefficients are, for example, dyes with a non-polar and / or less polarizable structure. Such dyes can, for example, come from the classes of anthraquinone, stilbene, azastilbene, azo or methine dyes. Azo dyes are preferred. Azo dyes with an absorption maximum of the ⁇ * band which is less than or equal to 400 nm, very particularly preferably less than 400 nm, are particularly preferred.
  • azo dyes have the following structure of formula (I) wherein
  • X 1 and X 2 are the same or similar
  • R ! and R 2 are independently hydrogen or a nonionic substituent and
  • n and n independently of one another represent an integer from 0 to 4, preferably 0 to 2.
  • the Hammett constants for example, can be used as a measure of the similarity of the electronic structure of the atom types or groups.
  • X 1 and X 2 are preferably -X r -R 3 or X 2 ' -R 4 ,
  • (CNR 8 -NR 5 ) - stand, R 3 , R 4 , R 5 and R 8 independently of one another for hydrogen, C, - to C 20 alkyl, C 3 - bis
  • X r -R 3 and X 2 ' -R 4 can represent hydrogen, halogen, cyan, nitro, CF 3 or CC1 3 ,
  • R 6 and R 7 independently of one another for hydrogen, halogen, C, - to C 20 -alkyl, C, - to C 20 -alkoxy, C 3 - to C 10 -cycloalkyl, C 2 - to C 20 -alkenyl or
  • alkyl, cycloalkyl, alkenyl and aryl radicals can in turn be replaced by up to 3
  • Residues from the series halogen, cyano, nitro, C, - to C 20 -alkyl, C, - to C 20 -alkoxy, C 3 - to C 10 -cycloalkyl, C 2 - to C 20 -alkenyl or C 6 - bis C 10 aryl can be substituted and the alkyl and alkenyl radicals can be straight-chain or branched.
  • Halogen is to be understood as fluorine, chlorine, bromine and iodine, in particular fluorine and
  • the recording material according to the invention is preferably polymeric or oligomeric organic, amorphous material, particularly preferably a side chain polymer, likewise particularly preferably a block copolymer and / or a graft polymer.
  • the main chains of the side chain polymer come from the following basic structures: polyacrylate, polymer methacrylate, polysiloxane, polyurea, polyurethane, polyester or cellulose. Polyacrylate and polymethacrylate are preferred.
  • the block copolymers consist of several blocks, at least one of which contains the copolymer systems described above.
  • the other blocks consist of unfunctionalized polymer scaffolds, which serve the purpose of thinning the functional block in order to set the required optical density.
  • the extension of the functional block is below the light wavelength, preferably in the range of less than 200 nm, particularly preferably less than 100 nm.
  • the block copolymers are polymerized, for example, via free-radical or anionic polymerization or via other suitable polymerization processes, possibly followed by a polymer-analogous reaction or by
  • the uniformity of the systems is in a range less than 2.0, preferably less than 1.5.
  • the molecular weight of the block copolymers obtained by radical polymerization reaches values in the range of 50,000, values greater than 100,000 can be set by anionic polymerization.
  • the dyes in particular the azo dyes of the formula (I), are covalently bound to these polymer skeletons, generally via a spacer.
  • X 1 or X 2
  • X 1 stands for such a spacer, in particular with the meaning X 1 - (Q '-T'-S 1 -,
  • i stands for an integer from 0 to 4, where for i> 1 the individual Q 1 can have different meanings,
  • T 1 stands for - (CH 2 ) p -, where the chain can be interrupted by -O-, -NR 9 -, or -OSiR , 0 2 O-,
  • S 1 stands for a direct bond, -O-, -S- or -NR 9 -,
  • p represents an integer from 2 to 12, preferably 2 to 8, in particular 2 to 4,
  • R 9 represents hydrogen, methyl, ethyl or propyl
  • R '° represents methyl or ethyl
  • R D to R 8 have the meaning given above.
  • Preferred dye monomers for polyacrylates or methacrylates then have the formula (II) wherein
  • R represents hydrogen or methyl
  • Particularly preferred monomers of the formula (II) are, for example:
  • the polymeric or oligomeric organic, amorphous material according to the invention can carry formanisotropic groups in addition to the dyes, for example of the formula (I). These are also covalently bonded to the polymer frameworks, usually via a spacer.
  • Shape anisotropic groupings have, for example, the structure of the formula (III)
  • A represents O, S or NC, to C 4 alkyl
  • X 3 stands for -X 3 ' - (Q 2 ) j -T 2 -S 2 -,
  • X 4 stands for X 4 ' -R 13 ,
  • R 5 , R 8 and R 13 independently of one another for hydrogen, C, - to C 20 alkyl, C 3 - bis
  • X 4 -R 13 can stand for hydrogen, halogen, cyan, nitro, CF 3 or CC1 3 ,
  • R 6 and R 7 independently of one another are hydrogen, halogen, C, - to C 20 -alkyl, C, - to C 20 -alkoxy, C 3 - to C 10 -cycloalkyl, C 2 - to C 20 -alkenyl or - to C, 0 aryl stand,
  • R ", R 12, R:> are independently hydrogen, halogen, cyano, nitro, C, - to C 20 - alkyl, C, - to C 20 alkoxy, phenoxy, C 3 - to C 10 cycloalkyl,
  • q, r and s independently of one another represent an integer from 0 to 4, preferably 0 to 2,
  • j represents an integer from 0 to 4, where the individual Q 'may have different meanings for j> 1,
  • T 2 stands for - (CH 2 ) p -, where the chain can be interrupted by -O-, -NR 9 -, or -OSiR 10 2 O-,
  • S 2 stands for a direct bond, -O-, -S- or -NR 9 -,
  • p represents an integer from 2 to 12, preferably 2 to 8, in particular 2 to 4, R 9 represents hydrogen, methyl, ethyl or propyl and
  • R 10 represents methyl or ethyl.
  • Preferred monomers with such shape-anisotropic groupings for polyacrylates or methacrylates then have the formula (IV)
  • R represents hydrogen or methyl
  • Particularly preferred shape-anisotropic monomers of the formula (IV) are, for example:
  • the alkyl, cycloalkyl, alkenyl and aryl radicals can in turn be substituted by up to 3 radicals from the series halogen, cyano, nitro, C 1 -C 20 -alkyl, C 1 -C 20 alkoxy, C 3 -C 10 -cycloalkyl, C 2 - to C 20 -alkenyl or C 6 - to C 10 -aryl can be substituted and the alkyl and alkenyl radicals can be straight-chain or branched.
  • Halogen is to be understood as meaning fluorine, chlorine, bromine and iodine, in particular fluorine and chlorine.
  • the oligomers or polymers according to the invention can also contain building blocks which are used primarily to lower the percentage of functional building blocks, in particular dye building blocks. In addition to this task, they can also be responsible for other properties of the oligomers or polymers, e.g. B. the glass transition temperature,
  • such monomers are acrylic or methacrylic acid esters of the formula (V)
  • R represents hydrogen or methyl
  • R 14 represents optionally branched C 1 -C 20 -alkyl or a radical containing at least one further acrylic unit.
  • Polyacrylates and polymethacrylates according to the invention then preferably contain, as repeating units, those of the formulas (VI), preferably those of the formulas (VI) and (VII) or of the formulas (VI) and (VIII) or of the formulas (VI), (VII) and (VIII)
  • the quantitative ratio between VI, VII and VIII is arbitrary.
  • the concentration of VI is, depending on the absorption coefficient of VI, between 0.1 and
  • VI and VII is between 100: 0 and 1:99, preferably between 100: 0 and 30:70, very particularly preferably between 100: 0 and 50:50.
  • the dyes of the formula (I) or the dye monomers of the formula (II) have a short-wave main absorption band ( ⁇ - ⁇ * band) and a longer-wave secondary absorption band (n- ⁇ * band).
  • the molar extinction coefficient ⁇ of this n- ⁇ * band is in the range 400 to 5,000 * 10 3 cm 2 / mol.
  • the polymers and oligomers according to the invention preferably have glass transition temperatures T g of at least 40 ° C.
  • the glass transition temperature can be determined, for example, according to B. Vollmer, Grundriß der Makromolekularen Chemie, pp. 406-410, Springer-Verlag, Heidelberg 1962.
  • the polymers and oligomers according to the invention have a weight average molecular weight of 5,000 to 2,000,000, preferably 8,000 to 1,500,000, determined by gel permeation chromatography (calibrated with polystyrene).
  • Graft polymers are prepared by free radical attachment of dye monomers of the formula (II) and, if appropriate, additionally of formanisotropic monomers of the formula (IV) and / or if appropriate additionally of monomers of the formula (V) to oligomeric or polymeric basic systems.
  • Such basic systems can be a wide variety of polymers, e.g. B. polystyrene, poly (meth) acrylates,
  • the radical attachment can follow by irradiation with light or by using radical generating reagents, e.g. B. tert-butyl hydroperoxide, dibenzoyl peroxide, azodisobutyronitrile, hydrogen peroxide / iron (II) salts.
  • radical generating reagents e.g. B. tert-butyl hydroperoxide, dibenzoyl peroxide, azodisobutyronitrile, hydrogen peroxide / iron (II) salts.
  • the intermolecular interactions of the structural elements of the formulas (VI) with one another or between the formulas (VI) and (VII) with one another are adjusted by the structure of the polymers and oligomers in such a way that the formation of liquid-crystalline order states is suppressed and optically isotropic, transparent non-scattering films, foils, Slabs or cuboids can be made.
  • the intermolecular interactions are still strong enough to cause
  • interaction forces occur between the side groups of the repeating units of the formula (VI) or between those of the formulas (VI) and (VII), which are sufficient for the photo-induced configuration change of the side groups of the formula (VI) to produce a so-called cooperative Realignment of the other side groups ((VI) and / or (VII)) causes.
  • optical anisotropy can be induced in the optically isotropic amorphous photochromic polymers ( ⁇ n to 0.4).
  • Order states are generated and modified, thus modulating the optical properties.
  • Polarized light is used as the light, the wavelength of which lies in the region of the absorption band, preferably in the region of the long-wave n- ⁇ * band of the repeating units of the formula (VI).
  • the polymers and oligomers can be prepared by methods known from the literature, for example according to DD 276 297, DE-A 3 808 430, Macromolecular Chemistry 187, 1327-1334 (1984), SU 887 574, Europ. Polym. 18,
  • Films, foils, plates and cuboids can be produced without the need for complex orientation processes using external fields and / or surface effects. They can be opened up by spin coating, dipping, pouring or other technologically easily controllable coating processes
  • the layer thickness is> 0.1 mm, preferably> 0.5 mm, particularly preferably> 1 mm.
  • a particularly preferred preparation process for layers in the millimeter range is the injection molding process.
  • the polymer melt is pressed through a nozzle into a shaping holder, from which it can be removed after cooling.
  • a preferred method of producing the recording material or the polymer according to the invention comprises a process in which at least one monomer is polymerized without a further solvent, preferably free-radically polymerizing, and particularly preferably initiated by free-radical initiators and / or UV light and / or thermally .
  • the process is carried out at temperatures between 20 ° C. and 200 ° C., preferably between 40 ° C. and 150 ° C., particularly preferably 50 ° C. and 100 ° C. and very particularly preferably around 60 ° C.
  • AIBN is used as the radical starter.
  • liquid monomers which are preferably olefinically unsaturated monomers, particularly preferably based on acrylic acid and methacrylic acid, very particularly preferably methyl methacrylate.
  • the proportion of the monomers of the formula (II) in the copolymers is preferably 0.1 to 99.9% by weight, particularly preferably 0.1 to 50% by weight, very particularly preferably 0.1 to 5% by weight. %> and in the best case 0.5 to 2 wt .-% o.
  • the method of holographic data storage is, for example, in LASER
  • the polymer films described above are irradiated by two coherent laser beams of a wavelength which causes the required light-induced reorientations.
  • One beam, the object beam contains the optical information to be stored, for example the intensity curve, which results from the passage of a light beam through a two-dimensional, checkerboard-like pixel structure (data page).
  • the object beam is brought to interference on the storage medium with the second laser beam, the reference beam, which is generally a flat or circular wave.
  • the resulting interference pattern is memorized in the storage medium as a modulation of the optical constants (refractive index and / or absorption coefficient). This modulation penetrates the entire irradiated area, in particular the thickness of the optical constants (refractive index and / or absorption coefficient). This modulation penetrates the entire irradiated area, in particular the thickness of the optical constants (refractive index and / or absorption coefficient). This modulation penetrates the entire irradiated area, in particular the thickness of the optical constants (refrac
  • the modulated storage medium acts as a kind of diffraction grating for the reference beam.
  • the intensity distribution resulting from the diffraction corresponds to the intensity distribution which started from the object to be stored, so that it can no longer be distinguished whether the light comes from the object itself or whether it results from the diffraction of the reference beam.
  • Different multiplexing methods are used to store different holograms at a sample position: wavelength division multiplexing, shift multiplexing, phase multiplexing, peristrophic multiplexing and / or angle multiplexing and / or others.
  • Angle multiplexing changes the angle between the storage medium in which a hologram was saved at the current angles and the reference beam. After a certain change in angle, the original hologram (Bragg-Mismatch) disappears: the incident reference beam can no longer be transferred from the storage medium to the reconstruction of the
  • the angle from which this occurs depends crucially on the thickness of the storage medium (and on the modulation of the optical constants generated in the medium): the thicker the medium, the smaller the angle by which the reference steel has to be changed.
  • the polymer systems described in this patent now have the great advantage that when writing a subsequent hologram, those in the storage medium deposited information of the previous holograms is not deleted and that more than 5 holograms, preferably more than 50, particularly preferably more than 100, very particularly preferably more than 500 and extremely preferably more than 1000 holograms can be written at one location on the storage medium.
  • the objects to be stored are data pages that are transmitted by a
  • Liquid crystal displays are generated. These data pages have 256 x 256 pixels, preferably 512 x 512 pixels, particularly preferably 1024 x 1024 data pixels.
  • Another object of the invention is a recording material for a holographic volume storage consisting of a polymeric or oligomeric organic, amorphous material which contains at least one group which interacts with electromagnetic radiation and optionally at least one shape-anisotropic grouping, characterized in that it has an optical density ⁇ 2, preferably ⁇ 1, very particularly preferably ⁇ 0.3.
  • the recording material can be a self-supporting film, or preferably in one
  • Multi-layer structure can be used for data storage.
  • This multilayer structure is, for example, a sandwich in which the actual recording medium is surrounded by at least one substrate.
  • the substrate can be transparent media with high optical quality, for example glass plates, quartz plates or plates made of polycarbonate.
  • High optical quality is understood to mean that the scattering efficiency, ie the quotient between light scattered on this sandwich and the incident light, is not less than 10 "4 , preferably not less than 10 °, very particularly preferably not less than 10 " 6 .
  • the sample can be exposed to the beam of a HeNe laser. The detection takes place via a CCD camera. Examples
  • the water formed during the reaction is separated on the water separator.
  • the reaction mixture is diluted with 150 ml of chloroform, washed several times with 100 ml of water and dried over Na 2 S0 4 .
  • the desiccant is filtered off and the chloroform is distilled off on a rotary evaporator to two thirds.
  • the dispersion was diluted 1:10 with water, spread on a glass plate and dried.
  • the transparent, slightly yellow film on the glass plate was irradiated with polarized light, cold light lamp KL 500 from Schott, (spot diameter 6 mm) for 10 min. Between the crossed polarizers, the illuminated spot could be seen brightly in a dark environment.
  • a solution of 1 mol%> of a monomer of formula (II) or of Example 2 and 0.052 grams of 2,2'-azoisobutyronitrile in 10 grams of methyl methacrylate was rinsed in a glass ampule with dry argon for 30 minutes. The ampule was sealed with a rubber stopper and annealed at 60 ° C for 7 days. The result was a transparent polymer cylinder. The polymer cylinder could be isolated by breaking the ampoule and removing the glass fragments. Another storage for 2 weeks at 60 ° C served to remove the residues of methacrylic acid methyl ester and to dissolve the internal stresses in the polymer block.
  • the PAP cylinder obtained in this way was cut into disks with a diameter of 17 mm and a thickness of 1.9 mm in the precision engineering workshop and then polished. These discs have the optical according to the invention
  • a copolymer with 10 mol% of the azo dye is produced analogously. Analogously, copolymer is produced from 1 mol% of the other monomers and 99 mol% of the methacrylic acid methyl ester.
  • a polymer from Example 3 is applied from a solution by means of spin coating to a 150 ⁇ m thick glass substrate.
  • the measuring point lying on the substrate is 600 nm.
  • the height of the refractive index n of the polymer layer is determined for the three spatial directions x, y (layer plane) and z (layer normal) using the prism coupling method.
  • the base of a prism is brought into close contact with the polymer layer.
  • the angles at which the polarized light from a laser couples into the layer and passes through it in a waveguide fashion provide information about its refractive index at the light wavelength. Every coupling is evident as a signal dip at a detector in reflection.
  • the refractive index in the direction of polarization can be determined.
  • the values for n x and ri y can be determined.
  • the value for n z can be determined. For this, one of the two spatial directions x or y must coincide with the plane of incidence.
  • the value of the refractive index of the direction chosen in this way (n x or n y ) is included in the calculation.
  • the refractive indices n x , n y and n z are determined on the sample before, during and after several exposures and deletions. The exposure happens through
  • Irradiation onto the polymer layer in a vertical incidence with laser light of wavelength ⁇ 514 nm.
  • the light intensity is 200 mW / cm 2 .
  • the light is linearly polarized in the x direction.
  • the orientation anisotropy induced in this way in the xy plane is deleted with polarization in the y direction.
  • the sample is measured untreated, after 200 s, exposure, after 500 s exposure and after 5000 s exposure.
  • the level of the refractive index of each spatial direction is a measure of the average number of chromophores oriented in this direction, because it correlates with the inducible polarization and this is mainly composed of the high molecular polarizabilities along each molecular axis. Since n x and n y are originally identical, there is a macroscopically isotropic distribution in the xy plane. The smaller value for n z indicates the planar molecular orientation, which was created by the manufacturing process. The first exposure successively leads to an orientation distribution with a reduced number of chromophores lying in the x direction.
  • a polymer from a monomer according to Example 2 is in the form of granules. It is placed on a glass support and heated to approx. 180 ° C. The polymer melts at this temperature. There are spacers on the glass substrate, e.g. made of Mylar film or glass fibers and another cover glass. This sandwich glass-polymer-glass creates layers in the range from 20 to 1000 ⁇ m.
  • An SHG serves as the writing source
  • Nd YAG laser (532 nm).
  • a spatial light modulator that creates a data mask of 1024 x 1024 pixels.
  • the intensity ratio of the reference to the object beam is 7: 1, the total power density falling on the sample is 200 mW / cm 2 .
  • a new hologram is written under this new angle configuration. This pre walk is repeated 100 times. After each writing process, in addition to the hologram just written, all previously written holograms are read out by setting the corresponding reference angle. Even after the 100 writes have been completed, the information is retained in all holograms.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Holo Graphy (AREA)
  • Optical Record Carriers And Manufacture Thereof (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
  • Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)

Abstract

Cette invention concerne des matériaux d'enregistrement holographique entrant dans le domaine des polymères photoadressables.
EP00912500A 1999-03-08 2000-02-23 Materiau d'enregistrement holographique Withdrawn EP1166188A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE19910248 1999-03-08
DE19910248A DE19910248A1 (de) 1999-03-08 1999-03-08 Holographisches Aufzeichnungsmaterial
PCT/EP2000/001479 WO2000054111A1 (fr) 1999-03-08 2000-02-23 Materiau d'enregistrement holographique

Publications (1)

Publication Number Publication Date
EP1166188A1 true EP1166188A1 (fr) 2002-01-02

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EP (1) EP1166188A1 (fr)
JP (1) JP2002539475A (fr)
KR (1) KR20010103044A (fr)
AU (1) AU3424700A (fr)
CA (1) CA2365934A1 (fr)
DE (1) DE19910248A1 (fr)
WO (1) WO2000054111A1 (fr)

Cited By (1)

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Publication number Priority date Publication date Assignee Title
WO2003029311A1 (fr) 2001-09-27 2003-04-10 Bayer Aktiengesellschaft Materiau d'enregistrement optique reinscriptible presentant une bonne solubilite

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10027153A1 (de) * 2000-05-31 2001-12-06 Bayer Ag Blockcopolymere zur optischen Datenspeicherung
EP1256602A1 (fr) * 2001-05-08 2002-11-13 Rolic AG Mélange dichroique
WO2006016725A1 (fr) 2004-08-13 2006-02-16 National Institute Of Advanced Industrial Scienceand Technology Compose azoique heterocyclique photosensible, son procede de production et moyen d'enregistrement de donnees optiques
US7897296B2 (en) 2004-09-30 2011-03-01 General Electric Company Method for holographic storage
DE102006012225A1 (de) * 2006-03-16 2007-09-20 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Optisches Element, Verfahren zu dessen Herstellung und Vorrichtung zur Durchführung des Verfahrens

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Publication number Priority date Publication date Assignee Title
DE4339862A1 (de) * 1993-03-30 1994-10-06 Agfa Gevaert Ag Flächenhafte Gebilde aus Seitengruppenpolymeren
US5496670A (en) * 1993-08-30 1996-03-05 Riso National Laboratory Optical storage medium
DE4431823A1 (de) * 1994-09-07 1996-03-14 Bayer Ag Verfahren zur Verstärkung von Information in photoadressierbaren Seitenkettenpolymeren
DE19703132A1 (de) * 1997-01-29 1998-07-30 Bayer Ag Photoadressierbare Seitengruppenpolymere mit hoher induzierbarer Doppelbrechung
DE19720288A1 (de) * 1997-05-15 1998-11-19 Bayer Ag Homopolymere mit hoher photoinduzierbarer Doppelbrechung

Non-Patent Citations (1)

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Title
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2003029311A1 (fr) 2001-09-27 2003-04-10 Bayer Aktiengesellschaft Materiau d'enregistrement optique reinscriptible presentant une bonne solubilite

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AU3424700A (en) 2000-09-28
KR20010103044A (ko) 2001-11-17
JP2002539475A (ja) 2002-11-19
CA2365934A1 (fr) 2000-09-14
WO2000054111A1 (fr) 2000-09-14
DE19910248A1 (de) 2000-10-05

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