Abstract: A method is disclosed for replicating (copying) a master hologram into a photosensitive layer to produce a copy of the hologram in a manner such that the copy of the hologram is an accurate and true replication of the master hologram with minimum interface-related defects. A holographic element containing a master hologram for use in contact copying is also disclosed.

Abstract: In order to prevent decrease in diffraction efficiency that is brought about when the diffraction peak wavelength shifts due to, for example, the shrinkage of a volume-hologram-recording photosensitive material layer 1, the present invention provides an original volume hologram film 10. The original volume hologram film 10 has a volume-hologram-recording photosensitive material layer 1 provided on a film 2, and an adhesive layer 8 provided on a film 9. The films 2 and 9 are affixed to each other with the layer 1 and 8 facing each other. The volume hologram has been recorded in the layer 1. The layer 8 can migrate an ingredient to the layer 1 to shift the diffraction peak wavelength to the opposite side.

Abstract: This invention relates to the field of holography, in particular to a method and a device for recording optical holograms by means of amorphous molecular semiconductor (AMS) films deposited on a glass substrate pre-covered with a transparent electric conducting sub-layer. More precisely, the invention relates to a method and device for registering optical holograms on AMS-films which operates in such a way that the AMS-films possess the maximum achievable information parameters: Holographic sensitivity, optimal spatial frequency of the transmitted characteristic, band parameters for the spatial frequencies of the transmitted characteristic, “signal-to-noise” ratio in the restored holographic image, reference and object beam intensities ratio during hologram registration, and cycling ability.

Abstract: A holographic information storage and retrieval system provides an all-optical reversible method to fix information in doped or undoped photorefractive materials. The fixed information is sufficiently stable to provide long term archival storage over a period of decades or more and can be read out non-destructively by a coherent reference beam. Holograms recorded in a photorefractive material are fixed when the material is irradiated with incoherent ultraviolet light. Hence, the holograms are preserved indefinitely against erasure by a coherent beam and against dissipation in dark storage. Holograms, which are fixed in the photorefractive material with incoherent ultraviolet light, are also erased with incoherent ultraviolet light, thus making the process reversible.

Abstract: The optical article of the invention, e.g., holographic recording medium or polymeric waveguide, is formed by mixing a matrix precursor and a photoactive monomer, and curing the mixture to form the matrix in situ. The reaction by which the matrix precursor is polymerized during the cure is independent from the reaction by which the photoactive monomer is polymerized during writing of data. In addition, the matrix polymer and the polymer resulting from polymerization of the photoactive monomer are compatible with each other. Use of a matrix precursor and photoactive monomer that polymerize by independent reactions substantially prevents cross-reaction between the photoactive monomer and the matrix precursor during the cure and inhibition of subsequent monomer polymerization. Use of a matrix precursor and photoactive monomer that result in compatible polymers substantially avoids phase separation. And in situ formation allows fabrication of articles with desirable thicknesses.

Abstract: The invention relates to improvements in security features in paper and other substrates and in particular to an activatable feature to warn of tampering. The invention further relates to a security feature for a security document comprising at least one activatable layer and at least one visually apparent masking layer, said at least one activatable layer comprising a composition which is generally non-mobile but which becomes mobile when wetted with a liquid, said composition further including at least one detectable component, in which under dry conditions said at least one masking layer wholly covers the activatable layer and renders it non-detectable.

Abstract: A method is provided for producing a holographic optical element that is comprised of at least one primary hologram (as defined herein) and at least one complementary hologram (as defined herein). The holographic optical element is useful as a security device, since it is relatively easily produced and yet is uncopyable in total. Also disclosed are methods for establishing the authenticity of the holographic optical element.

Abstract: An improved method and apparatus for applying discrete area holograms or other optical devices directly onto documents or other substrates in a continuous process analogous to the operation of a printing press. The continuous process is carried out in a vacuum chamber in which at least two process steps are performed in sequence: the formation of a micro-grooved discrete resin area and a localized coating of it with a reflective or refractive material layer. The formation of the micro-grooved resin area can be accomplished by electron beam curing of the resin. The localized coating of the micro-grooved resin can be done by sputtering. One or more other steps, including pre-coating, post-coating and partial removal of the reflective or refractive layer, may also be carried out as part of the continuous process within the vacuum chamber.

Abstract: Charge-transfer materials are demonstrated to be useful for generating femtosecond holographic gratings. Using semiconducting polymers sensitized with varying concentrations of C60, absorption holographic gratings with diffraction efficiencies of 1.6% were recorded with individual ultrafast laser pulses; the diffraction efficiency and time decay of the gratings were measured using nondegenerate four-wave mixing. High quantum efficiency for electron transfer reduces the effects of early recombination which otherwise limits the density of excitations in pure polymers, and the metastability of the charge transfer enables tuning of the decay dynamics by controlling the concentration of acceptors in the mixture.

Abstract: There is described an image-recording medium and an image-reading method, which make it possible to improve reading accuracy of information by avoiding duplication of an optical variable image with the information. The image-recording medium includes a substrate, an image-receiving layer provided on the substrate and an optical variable layer provided on the substrate, wherein at least a part of the optical variable layer includes an optical variable image, and the optical variable image is formed in a manner such that the optical variable image, overlapping with an image recorded on the image-receiving layer, emerges in a first direction, while the optical variable image, overlapping with an image recorded on the image-receiving layer, does not emerge in a second direction.

Abstract: A photosensitive composition and A photosensitive medium for volume hologram recording comprises a photopolymerization reactive compound (a monomer) and any one of the following binder: (a) an organic-inorganic hybrid polymer obtainable by copolymerizing an organometallic compound of the formula 1 “R1m M1 (OR2)” and an ethylenic monomer and/or its hydrolyzed polycondensate; (b) an organic-inorganic hybrid polymer obtainable by copolymerizing an organometallic compound of the formula 3 “R4m Si (OR5)n” and an ethylenic monomer and/or its hydrolyzed polycondensate; and (c) a binder resin bonded to a metal or a combination use of a binder resin containing a hydroxyl group and/or carboxyl group and a metal chelate compound.

Abstract: The present invention relates to a volume hologram laminate with low generation of spotty hologram flaws in the volume hologram layer even when kept under pressurized conditions during storage, and to a volume hologram laminate-fabricating label. The volume hologram laminate 1 of the invention has a first adhesive layer 3, a volume hologram layer 5, a second adhesive layer 4 and a surface protective film 6 formed in that order on a substrate 1, wherein the volume hologram layer is a hologram recording in a recording material comprising a matrix polymer and a photopolymerizable compound, having a glass transition point of 30° C.-70° C. and a dynamic storage elastic modulus of 5×105 Pa-5×107 Pa at 50° C. when measured at 6.28 rad/s, and the second adhesive layer has a dynamic storage elastic modulus of no greater than 5×104 Pa or at least 2.5×105 Pa at 50° C. when measured at 6.28 rad/s.

Abstract: Disclosed is a storage medium which comprises strontium barium niobate single crystal containing europium and cerium as impurities. The material may be used in which the strontium barium niobate has a chemical formula: SrxBa1-xNb2O6 where x satisfies 0.25≦x≦0.75. Further, small amounts of cerium and europium are added to a main component comprised by strontium, barium, niobate and oxygen. The optical material can be used in various optical devices such as a holographic storage medium, a phase conjugate mirror and an optical amplifier.

Abstract: A method of fabricating a hologram screen having a large visual range and a hologram imaging apparatus used for the particular method of fabricating the hologram screen are disclosed. A plurality of mirrors (3) extended toward a plurality of photosensitive members (5) are arranged at a plurality of end portions (21), respectively, of a light diffuser (2). At least a reference beam (41) and object beams (42) passed through the light diffuser (2) are radiated on a plurality of the photosensitive members (5) individually thereby to form a plurality of holograms. These holograms are integrated with each other by being arranged two-dimensionally thereby to fabricate a hologram screen. Among the mirrors (3), a reference beam-side mirror (31) arranged nearer to the light source of the reference beams (41) is extended from the light diffuser (2) by a length varied with the position of the photosensitive member (5) to be exposed.

Abstract: The invention relates to improvements in security features in paper and other substrates and in particular to an activatable feature to warn of tampering. The invention further relates to a security feature for a security document comprising at least one activatable layer and at least one visually apparent masking layer, said at least one activatable layer comprising a composition which is generally non-mobile but which becomes mobile when wetted with a liquid, said composition further including at least one detectable component, in which under dry conditions said at least one masking layer wholly covers the activatable layer and renders it non-detectable.

Abstract: A method for impressing holographic images or holograms in the surface of metal objects such as aluminum cans, sheet metal or metal foil. The surfaces of metal shims and print rolls bearing holograms are hardened as by coating them with thin amorphous diamond coatings or diamond like coatings so the holograms can be embossed into many thousands of metal objects with clarity and consistency.

Abstract: Multi-domain, phase-compensated, differential-coherence detection of photonic signals for interferometric processes and devices may be manufactured holographically and developed in situ or with an automatic registration between holograms and photonic sources in a single frame. Photonic or electronic post processing may include outputs from a cycling or rotation between differently phased complementary outputs of constructive and destructive interference. A hyper-selective, direct-conversion, expanded-bandpass filter may rely on an expanded bandpass for ease of filtering, with no dead zones for zero beat frequency cases. A hyper-heterodyning, expanded bandpass system may also provide improved filtering and signal-to-noise ratios. An ultra-high-resolution, broadband spectrum analyzer may operate in multiple domains, including complex “fingerprints” of phase, frequency, and other parameters.

Abstract: A method for fabricating an error-free linear position encoder incorporates the generation of fringes on a holographic plate by the interference of light from two point sources. The fringes are projected onto a curved holographic plate without intervening optical elements, the curve being such that the fringes have a constant pitch along the surface of the plate. A methodology for generating such a curve includes the creation of a graphic representation of the hyperbolic fringes generated by the interference between two coherent point sources, which would fall on an appropriately curved holographic plate. A numerical technique derived from the graphic representation produces a “constant-pitch” curve such that all of the fringes projected onto the curve are equidistant. The holographic plate, coated with a photosensitive material, is fabricated or formed in the shape of the constant-pitch curve.

Abstract: An optical information recording and reproducing apparatus, which detachably supports a holographic memory formed of a photorefractive crystal, includes a portion for supplying a coherent reference light beam at a first wavelength into the holographic memory; a portion for supplying a coherent signal light beam at the first wavelength, modulated in accordance with image data, into the memory to produce an optical interference pattern with the reference light within the memory; a portion for supplying a gate light beam at a second wavelength into the memory for activating or deactivating an index grating in accordance with the presence or absence of the optical interference pattern to enhance a photo-sensitivity of the memory; a detector for detecting diffraction light from the index grating of the memory by the irradiation of the reference light beam; and a portion for changing and regulating a light intensity of the gate light beam.

Abstract: A method and apparatus is disclosed for creating a structure, such as a grating (45) in a photosensitive material (40). The method and apparatus relies upon creating at least two coherent beams of light (33, 38) and reflecting them, in a counter propagating manner, around a series of reflective elements (35, 37) along substantially equivalent paths so that the coherent beams interfere at a structure staging area (45). The structure staging area can then be utilized to create grating structures or the like having improved qualities.

Abstract: Disclosed is a holographic recording medium. The novel holographic recording mediums disclosed herein comprises: a) at least one polyfunctional epoxide monomer or oligomer which undergoes acid initiated cationic polymerization. Each epoxide in the monomer or oligomer is linked by group comprising a siloxane to a silicon atom and each monomer or oligomer has an epoxy equivalent weight of greater than about 300 grams/mole epoxide; b) a binder which is capable of supporting cationic polymerization; c) an acid generator capable of producing an acid upon exposure to actinic radiation; and optionally d) a sensitizer.

Abstract: New photosensitive acrylic material compositions for fabrication of holographic recording materials (HRMs) are provided. These compositions are comprised of polymerizable acrylic monomers and light absorbing dyes, and when polymerized they are thermally stable, light sensitive, hard and inert to common chemicals. Methods of fabricating HRMs with symmetric concentration distribution of the dye are also provided.

Abstract: The invention provides a partial metallic hologram wherein a light reflecting layer is formed easily at a low price and the light reflecting layer and the hologram region are formed in a pattern having an arbitrary shape, and a method of producing the same. A metallic hologram comprises a light reflecting layer, wherein the light reflecting layer is formed by coating or printing with a high brightness coating agent.

Abstract: A method for making wire grid optical elements by preferentially depositing material on a substrate is disclosed. Material can be preferentially deposited by directing an electromagnetic interference pattern on to a substrate to selectively heat areas of the substrate coincident with the interference pattern maxima. The substrate can then be exposed to gas phase material that is capable of preferentially accumulating on surfaces based on surface temperature.

Abstract: The invention relates to a liquid crystal display device which enables a visual field range to be made wide and luminance drops to be reduced, so that bright displayed images can be presented, and provides a liquid crystal display device comprising, in order from a side of backlight 11, backlight 11, scatter plate 12, and liquid crystal element 20, wherein a transmission type of hologram scatter plate 13 is located in front of a display surface of liquid crystal display element 20. Hologram scatter plate 13, because of having been fabricated by means of single-step or two-step exposure, enables light more or less scattered through scatter plate 12 to be limitedly scattered within a given wide visual field range, so that bright displayed images can be presented over a wide visual field range yet with a reduced luminance drop. Scatter plate 12 may be omitted.

Abstract: It has been found that holographic images can be formed on the surfaces of plastic products or the plastic packaging for products. The elastic preferably is a thermoplastic that can flow into the narrow spacings that form the holographic image. The holographic image is formed while the product or packaging is being formed. These can be formed by injection molding, blowmolding, injection stretch blowmolding and thermoforming. A shim bearing the image of the hologram is placed in the mold and the plastic injected or otherwise flowed or placed in the mold. Upon the plastic under pressure being in contact with the shin in the mold, the shin will impart a holographic image into the plastic. The product or package is cooled and then is in a form for use.

Abstract: The invention relates to novel monodisperse or polydisperse compounds, in general named DNO (diamino acid N&agr;-substituted oligopeptides), preferably low molecular weight polypeptides, e.g., based on ornithine, lysine, diaminobutyric acid, diaminopropionic acid, aminoethylglycine or other amino acids or peptides having azobenzenes or other physicially functional groups, e.g., photoresponsive groups, as side chains. These compounds may be synthesized using solid phase peptide synthesis techniques. Materials, e.g., thin films, comprising such compounds may be used for optical storage of information (holographic data storage), nonlinear optics (NLO), as photoconductors, photonic band-gap materials, electrically conducting materials, electroluminescent materials, piezo-electric materials, pyroelectric materials, magnetic materials, ferromagnetic materials, ferroelectric materials, photorefractive materials, or materials in which light-induced conformational changes can be produced.

Abstract: Novel volume holographic elements were made from Bragg diffractive gratings in photo-thermo-refractive (PTR) glass with absolute diffraction efficiency ranging from greater than approximately 50% up to greater than approximately 93% and total losses below 5%. Both transmitting and reflecting volume diffractive elements were done from PTR glasses because of high spatial resolution enabling recording spatial frequencies up to 10000 mm−1. The use of such diffractive elements as angular selector, spatial filter, attenuator, switcher, modulator, beam splitter, beam sampler, beam deflectors controlled by positioning of grating matrix, by a small-angle master deflector or by spectral scanning, selector of particular wavelengths (notch filter, add/drop element, spectral shape former (gain equalizer), spectral sensor (wavelength meter/wavelocker), angular sensor (pointing locker), Bragg spectrometer (spectral analyzer), transversal and longitudinal mode selector in laser resonator were described.

Abstract: Polymer techniques are used to reduce the feature size in electrical or mechanical processes. A first embodiment uses a light sensitive polymer. A first illumination forms a lens structure. A second illumination is focused by that lens structure to form a final feature. The lens can then be removed. A second embodiment uses holographic techniques to pattern polymers and form consistent pores within the polymers.

Abstract: The present invention relates to compositions useful for optically recording or storing data by stimulating a composition having a refraction modulating composition, where a stimulated region of the composition represents one kind of data and a non-stimulated region of the composition represents another kind of data. The present invention also relates to methods of optically recording data utilizing the compositions of the present invention, as well as to optical data storage devices and optical data storage elements which utilize the optical data storage compositions of the invention.

Abstract: A multilevel diffractive optical element comprising a base and a plurality of phase zones having phase levels of a substantially identical height h, each phase zone being defined by a local modulation depth d and a local number of phase levels &xgr;=d/h, the local number of phase levels &xgr; per phase zone being a real number, an integer of which defines the number of complete levels in the phase zone, which complete levels have identical widths, and a fraction of which, in at least one phase zone, defines an incomplete level which is narrower than the complete levels, said local number of phase levels &xgr;=&xgr;(x, y) varying among different phase zones so as to provide corresponding variation of said local modulation depth d=d(x, y) whereby local diffraction efficiencies and consequently an overall diffraction efficiency of the optical element is arbitrarily controlled.

Abstract: A system and method of preparing artwork for a laser foil die implement prism lines designed to interact with the diffraction grating on a layer of laser hot foil. Artwork may be selectively segmented into discrete regions; prism lines may be created by assigning a halftone value, a frequency value, and an angle for each region of the artwork. A system and method of creating a laser foil die transfer such artwork and prism lines to a blank die; when created in accordance with the present invention, a die may transfer prism lines to a layer of laser foil applied to a substrate.

Abstract: Disclosed is an improvement in an optical information recording method by utilizing a unique phenomenon in which, when a thin film of a polymeric compound having a structure of azobenzene is irradiated spotwise with a light beam of a specified wavelength, a pattern of rugged surface with recesses and raises is resulted by the migration of the polymer molecules from the strongly irradiated area to the weakly irradiated area. The improvement has an object to increase the photosensitivity of this phenomenon by simultaneously irradiating the polymeric thin film with a second or bias light beam of a larger cross section to envelop the irradiation spot by the first or writing light beam.

Abstract: The photonic crystal material has a 3-D periodic structure with a periodicity that varies on a length scale comparable to the wavelength of electromagnetic radiation. The 3-D periodic structure is produced by irradiating photosensitive material with electromagnetic radiation such that interference between radiation propagating in different directions within the sample gives rise to a 3-D periodic variation in intensity within the sample. Thereafter the irradiated material is developed to remove the less or more irradiated regions of the material to produce a structure having 3-D periodicity in the refractive index of the composite material. 3-D photonic material is particularly suited to use as low-loss waveguides and as a control with lasers to limit the number of modes into which a laser may emit radiation.

Abstract: A multilayer polymer film has an optical stack including a plurality of alternating polymer layers with skin layers having mechanical, optical, or chemical properties differing from those of the layers in the optical stack. In one embodiment, the multilayer polymeric film has one or more holograms that provide attractive and useful optical effects.

Abstract: The invention provides a hologram transfer foil comprising a substrate and a transfer layer laminated thereon, said transfer layer comprising a surface protective layer, a thermoplastic resin layer, a hologram layer and a heat seal layer in this order. The hologram transfer foil is applied on the heat seal layet side to an application member. In this case, a peel force between the substrate and the surface protective layer is smaller than that between adjacent layers in other layers. This hologram transfer foil enables a hologram image, etc. to be reconstructed in an uninterrupted manner, and is improved in terms of transferability and productivity.

Abstract: The present invention provides a volume hologram laminate by which a desirable reproduced wavelength is controlled and set optionally. The laminate has a first adhesive layer 3, a volume hologram layer 5, a second adhesive layer 4 and a surface protecting film 6 formed on a substrate 2 in the described order, wherein a substance for shifting a recorded wavelength to the volume hologram layer is contained in the first and/or the second adhesive layer(s) and a reproduced wavelength of hologram recorded in the volume hologram layer is controlled with shifting the substance between the layers.

Abstract: New photosensitive acrylic material compositions for fabrication of holographic recording materials (HRMs) are provided. These compositions are comprised of polymerizable acrylic monomers and light absorbing dyes, and when polymerized they are thermally stable, light sensitive, hard and inert to common chemicals. Methods of fabricating HRMs with symmetric concentration distribution of the dye are also provided.

Abstract: The hologram recording sheet according to the invention is made up of a base film and hologram sensitive materials sensitive to different wavelength regions formed therein in a desired pattern, or a film and at least two hologram recording sensitive materials sensitive to different wavelength regions laminated on the film with a transparent plastic spacer layer located therebetween, thereby enabling the required diffraction light wavelengths to be recorded on the required sites without producing unnecessary interference fringes. At least two hologram recording sensitive materials sensitive to different wavelength regions are formed on different sites on a film in dotted or striped configuration, the size of which is up to 200 mm or at least twice as large as the thickness of the sensitive material layers, thereby enabling regions diffracting light of different wavelengths to be formed in the form of independent sets of interference fringes.

Abstract: There are disclosed the following three types of optical recording film:

Abstract: A method for fabricating a capacitor electrode on a semiconductor substrate includes the steps of: forming a conducting layer over the semiconductor substrate; forming a photoresist layer over the conducting layer; pattering the photoresist layer through an interfering exposure step; and pattering the conducting layer using the patterned photoresist layer as a mask, thereby forming a capacitor electrode.

Abstract: A holographic information storage and retrieval system provides an all-optical reversible method to fix information in doped or undoped photorefractive materials. The fixed information is sufficiently stable to provide long term archival storage over a period of decades or more and can be read out non-destructively by a coherent reference beam. Holograms recorded in a photorefractive material are fixed when the material is irradiated with incoherent ultraviolet light. Hence, the holograms are preserved indefinitely against erasure by a coherent beam and against dissipation in dark storage. Holograms, which are fixed in the photorefractive material with incoherent ultraviolet light, are also erased with incoherent ultraviolet light, thus making the process reversible.

Abstract: The invention provides an optical lens having a combination volume holographic optical element that provides a diffractive optical power. The optical lens has a programmed activating angle in which the holographic optical element provides a diffractive optical power. The invention also provides a method for producing a multilayer holographic element suitable for the optical lens.

Abstract: Lithography processes that use multiple layers require registration between layers. The accuracy requirement depends on the application of the lithograph. For microlithography, the registration requirement could be less than one micron. Systems that use lenses for imaging such as optical steppers can image conventional alignment marks through those lenses. A unique microlithography system that employs holograms has properties that are not compatible with known alignment techniques. The present invention is a new system for alignment of holographic microlithography elements.

Abstract: A pattern formation method wherein a very small pattern composed of a desired element (atoms) is formed directly on a substrate by using atomic beam hologram technology. Quantum coherent reflection of an atomic wave is utilized. A coherent atomic beam is irradiated as a material wave, for example, upon a hologram of the transmission type to modulate the atomic beam with pattern information included in the hologram. The atomic beam having passed through and diffracted by the hologram is introduced to a reflecting plane so that the atomic beam may be quantum coherent reflected by the reflecting plane, and the atomic beam thus reflected is introduced into a substrate. A binary (two-value) hologram produced by computer synthesis is used suitably as the hologram. A hologram of the potential control type may be also used.

Abstract: A thickness of each hologram lens for forming a hologram color filter is set so as to be smaller as the wavelength of light to be diffracted by each hologram lens is shorter. A thin plate glass layer is bonded to a surface of the hologram color filter such that it is in a firm contact therewith by adhesive agent and a sum of the thickness of the thin plate glass layer and thickness of the adhesive agent is smaller than the shortest focal length of the focal lengths in glass of a plurality of the hologram lenses. As a result, light diffracted and divided by the hologram color filter is focused on a picture element electrode of a corresponding color properly thereby eliminating deterioration of color reproduction due to mixing of colors. Further, upon production of the hologram color filter from hologram recording material, an influence of a fringe rotation is compensated.

Abstract: The invention provides a hologram transfer foil 1 comprising, in order from top to bottom, a substrate 7, a volume hologram layer 2 releasably stacked on substrate 7 and comprising a volume hologram in a cured resin layer, a first heat seal layer 3 and a second heat seal layer 4. In use, the hologram transfer foil 1 is applied on the second heat seal layer 4 side over an application member. The adhesion force of volume hologram layer 2 to the application member is larger than a material fracture force for the volume hologram layer or the application member, so that the hologram transfer layer can be applied by thermo-compression to the application member. This hologram transfer foil is useful for illegal copying of the hologram layer because when the volume hologram is forcibly peeled from the application, a material fracture of the volume hologram layer or application member occurs.

Abstract: High storage densities using a holographic system are achievable using a stratified medium while maintaining a relatively high selectivity upon reconstruction of the stored images. Such combination of high density and high selectivity is achievable by employing a stratified medium and a recording process where selectivity does not vary with recording thickness.

Abstract: A photoactive medium has a complex format grating written thereon, the complex format grating including at least three component gratings, each of the component gratings characterized by a unique grating vector. Methods for writing the complex format grating include the steps of providing a photoactive medium; and focussing a plurality of pairs of mutually coherent light beams into a focal plane in the medium.

Abstract: The present invention comprises an optical data storage system utilizing a host material and molecules that exhibit non-linear absorption dissolved therein. The non-linear absorbing molecules allow for energy in the form of heat to be generated during the optical data storage process. This heat provides for localized alterations to occur in the pre-formatted holographic grating. The non-linear feature of these molecules allow for alterations to occur at specific depths and locations within the storage medium while limiting the secondary effects on other locations within the storage medium. The molecules exhibiting non-linear absorption may be selected from the group of molecules exhibiting two-photon absorption or reverse saturable absorption. The invention also comprises a method for preparing the optical storage medium, an optical data storage device comprising the optical data storage medium and having a format hologram stored within the medium.