Abstract: A method for printing a pattern from a hologram mask into a photosensitive layer on a substrate, which method includes arranging the hologram mask on a coupling element, arranging the substrate so that it is substantially parallel with the hologram mask and separated from it by an amount substantially corresponding to the focal distance of the hologram mask, reconstructing the pattern recorded in the hologram mask by scanning an exposure beam of substantially collimated across the hologram mask while continuously measuring the local separation between the hologram mask and substrate in at least two locations where the pattern is being reconstructed by scanning at least two focus beams across the hologram mask, and continuously adjusting the separation and the angle of tilt between the hologram mask and substrate in order that the pattern reconstructed from the hologram mask is accurately focussed onto the photosensitive layer on the substrate.

Abstract: Described are holographic storage mediums and method of making holographic storage mediums. The holographic storage mediums may have write components that bind to the matrix to form a pattern in the media. The holographic storage mediums may also be rewriteable.

Abstract: It is a main object of the present invention to provide a volume hologram layer with good foil cutting property which is used for a volume hologram transfer foil and the like. The present invention provides a volume hologram layer wherein when the layer thickness thereof is 20 ?m, breaking strength is in a range from 10 MPa to 30 MPa and breaking strain is in a range from 0.1% to 3% at 25° C., and breaking strength is in a range from 0.1 MPa to 1 MPa and breaking strain is in a range from 0.1% to 5% at 130° C., to thereby solve the above problem.

Abstract: A method for manufacturing water-based laser hologram papers has acts of entirely or partially coating water-based varnish on a printed paper substrate, subjecting the paper substrate to a mirror treatment, and entirely or partially molding the paper substrate with laser compressing operations. By substituting PVC or PET plastic membranes with decomposable water-based varnish, the laser hologram paper is environmental friendly to reduce pollution and is also breakable to provide counterfeit-deterring efficiency. Moreover, material cost of the plastic membranes is eliminated to reduce manufacturing cost of the laser hologram papers.

Abstract: A method for controlling the shape of the area machined by a pulse of laser light on a surface, such that the shape has a desired elliptical shape with its major axis aligned in a desired direction and the length of this major axis is less than or equal to a diameter of a beam spot. The pulse is generated and focused to the beam spot within a target area. The polarization of the pulse is adjusted to be elliptically polarized with an axis of the polarization ellipse oriented in the desired direction. The ellipticity of the polarization of the pulse is adjusted such that the pulse of laser light has contours of constant machining capacity on the workpiece surface, which have a similar shape to the desired shape. The fluence of the pulse light is controlled such that the area machined by the pulse is substantially the desired shape.

Abstract: The present invention includes an optical system to control and optimize molecular reorientation for information storage. A preferred embodiment of the invention utilizes light sources emitting at wavelengths centered on or around the absorption bands of the storage medium. The light can be selectively polarized to control orientation of molecular components of organic material to provide non-volatile storage of large amounts of information. This provides an alternative to magnetic, electric, magneto-optical, or electro-optical methods which are complex and expensive. The all-optical holographic method in accordance with the present invention provides a storage system with extremely high memory capacity. In accordance with another aspect of the present invention, a system for optically storing and retrieving data includes optically recording (writing) and retrieving (reading) with the same wavelength beam, for example, without additional conditions such as an electric or magnetic field.

Abstract: A holographic recording and reconstructing apparatus includes a light source having a variable oscillation wavelength; a temperature sensing unit operable to sense temperature; and a control unit operable to record information about a temperature sensed by the temperature sensing unit on a holographic recording medium during recording, to obtain the information about the temperature from the holographic recording medium and obtain a temperature sensed by the temperature sensing unit during reconstruction, to determine the amount of wavelength shift to counteract the effects of a change in the dimension of the holographic recording medium between recording and reconstruction based on the difference between the temperatures, and to shift the oscillation wavelength of the light source by the determined amount.

Abstract: In the present invention, a photosensitive layer of an optical recording medium includes a photo-responsive high-molecular compound comprising a photo-responsive group (e.g., an azobenzene derivative) which is geometrically isomerized by light radiation, and a liquid crystal linear mesogen group (e.g., a biphenyl derivative), wherein the photo-responsive group and the linear mesogen group are respectively bonded as side chains. The invention provides an optical recording medium enabling large scale recording by making the photosensitive layer thick without impairing recording characteristics. The photo-responsive high-molecular compound preferably comprises an aromatic ring on a main chain. Further, the photo-responsive high-molecular compound preferably comprises a structural unit which is capable of forming a liquid-crystalline or crystalline polymer and a structural unit which is capable of forming an amorphous polymer.

Abstract: Disclosed is a holographic recording medium and methods of manufacturing the holographic recording medium. The example of the medium has a recording layer containing a three dimensionally cross-linked polymer matrix including an epoxy resin, a radically polymerizable monomer, and a photo radical polymerization initiator. The radically polymerizable monomer comprises both N-vinylcarbazole (VC) and N-vinylpyrrolidone (VP) or N-vinylcarbazole alone. The weight ratio of N-vinylcarbazole (VC) to the sum of N-vinylcarbazole (VC) and N-vinylpyrrolidone (VP), i.e., (VC/(VC+VP)), is not smaller than 0.75 and not larger than 1.0.

Abstract: The chiral agent used for liquid crystal according to the present invention comprises a phosphoric acid amide represented by General Formula (1) below: in General Formula (1), the binaphthyl structure has an axial asymmetry of either (R) or (S); R1 and R2 may be identical or different and each represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkenyl group, an alkynyl group or an alkoxy group; R3 and R4 may be identical or different and each represents a hydrogen atom, an alkyl group or an aryl group.

Abstract: Disclosed is a holographic optical recording medium, comprising a recording layer containing a three dimensionally cross-linked polymer matrix, a radically polymerizable compound, and a photo radical polymerization initiator, the three dimensionally cross-linked polymer matrix comprising a cured material of a reaction product between a diglycidyl ether and an amine, the diglycidyl ether being selected from the group consisting of 1,6-hexanediol diglycidyl ether and diethylene glycol diglycidyl ether.

Abstract: The main object is to provide a volume hologram transfer foil showing an excellent foil cutting property and capable of being transferred easily to a transferred body. This object is solved by providing a volume hologram transfer foil comprising a substrate, a volume hologram layer formed on the substrate and a heat sensitive adhesive layer formed on the volume hologram layer, wherein the volume hologram layer has a breaking strain at 25° C. in a range of 0.5% to 15% and a breaking strain at 120° C. in a range of 0.5% to 30%, and the heat sensitive adhesive layer has a breaking strain at 25° C. in a range of 0.5% to 15%.

Abstract: A method for manufacturing water-based laser hologram papers has acts of entirely or partially coating water-based varnish on a printed paper substrate, subjecting the paper substrate to a mirror treatment, and entirely or partially molding the paper substrate with laser compressing operations. By substituting PVC or PET plastic membranes with decomposable water-based varnish, the laser hologram paper is environmental friendly to reduce pollution and is also breakable to provide counterfeit-deterring efficiency. Moreover, material cost of the plastic membranes is eliminated to reduce manufacturing cost of the laser hologram papers.

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: A reference beam is deflected by an angularly rotating mirror, and applied to a hologram recording medium at a set incident angle. The relevant applied reference beam and a signal beam are superposed within the hologram recording medium, and light intensity distribution of the resultant interference fringes is recorded as a hologram. The reference beam incident on the hologram recording medium is partially transmitted through the hologram recording medium. The relevant transmitted reference beam passes through a quarter wave plate to be incident on a hologram element. The relevant incident reference beam has its traveling direction changed into a reverse direction by the hologram element regardless of its incident angle, follows the same optical path as the incoming path, and is applied again to the hologram recording medium.

Abstract: A polarization-selective diffractive optical element includes a liquid crystal polymer film supported by a substrate. The liquid crystal polymer film includes an array of pixels, each pixel encoded with a fixed liquid crystal director such that each liquid crystal director is aligned in a common plane perpendicular to the liquid crystal polymer film and provides a predetermined pattern of out-of-plane tilts. A size of the pixels in the array and the predetermined pattern are selected such that the liquid crystal polymer film forms a phase hologram for diffracting light polarized parallel to said common plane and a zeroth order diffraction grating for light polarized perpendicular to the said common plane. The non-etched and flat phase hologram is suitable for a wide range of applications.

Abstract: A rotary apertured interferometric lithography (RAIL) system that includes interferometric lithography tools, a mask with a slit preferably with an arc shape, and a rotating stage is disclosed. The RAIL system could create a servo pattern of a recording-head trajectory of a hard disk drive in a master for magnetic-contact printing. The master can could be used to form arrays of sub-micron sized magnetic elements on a magnetic disk media for high-density magnetic recording applications.

Abstract: Producing a digital hologram-in a storage medium includes: (i) focusing a write beam onto the storage medium; (ii) moving the write beam two-dimensionally relative to the storage medium; (iii) focusing a scanning beam onto a beam-guiding mask having a plurality of tracks; (iv) moving the scanning beam two-dimensionally relative to the mask, the movement of the scanning beam being coupled with the movement of the write beam; (v) generating a position control signal when the position of the scanning beam deviates from the scanned track by a predefined value; (vi) controlling the position of the write beam on the storage medium with the aid of the position control signal; and (vii) writing the hologram by introducing radiation energy point by point, the intensity of the write beam being controlled as a function of the position of the write beam on the storage medium.

Abstract: A host matrix—normally a binder such as cellulose acetate propionate in a solvent such as acetone—contains a radiation-polymerizable photopolymer—normally a monomer like dipentaerythritol pentaacrylate in combination with a crosslinker like 1-vinyl-2-pyrrolidinone, an initiator like N-phenyl glycine, and/or a photosensitizer like camphor quinine—that is initially uniformly doped with a stable dye—typically Rhodamine B and/or Bodipy Red—that photoinitiates photopolymerization. Upon selective exposure of certain regions of the matrix by radiation, most normally laser light radiation, the dye will initially migrate and redistribute itself to radiatively-exposed regions until, dye migration being substantially complete, photopolymerization will occur, locking the migrated dye in place at a relatively higher concentration at the selectively exposed regions. The dye therein stably located can be optically detected by, preferably, light-radiation-stimulated fluorescence.

Abstract: A diffractive optical element such as a diffuser, diffraction grating, and/or hologram, can be manufactured by using a surface relief pattern on a surface of a surface relief tool. A layer of curable material is physically contacted with the surface relief pattern on the surface of the surface relief tool to thereby imprint the pattern on a surface of the layer. Diffractive features are formed in the layer by propagating energy through the surface relief tool and into the layer such that refractive index variations corresponding to the pattern are created in the layer. The resultant product is a diffractive optical element comprising a layer of material having diffractive features formed by a predetermined pattern of refractive index variations. The diffractive features originate at an undulating boundary and extend only from one side of the boundary into the material. The undulating boundary has an undulating pattern that corresponds to the predetermined pattern of refractive index variations.

Abstract: High efficiency reflective volume Bragg gratings with chirped gratings recorded in photo-thermo-refractive glass having an absolute diffraction efficiency exceeding 95% in transmitting and reflecting modes are used to stretch and/or compress ultrashort laser pulses with high efficiency. Robustness, compactness, thermal and laser stability along with placement of multiple elements in the same space provides femtosecond laser system with high efficiency of stretching and re-compression of femtosecond pulses.

Abstract: The present invention relates to a method of producing digital holograms in a storage medium, in which the technical problem of writing computer-generated holograms by means of optical lithography as quickly as possible and with little effort with simultaneous accurate control of the timed triggering and the positioning of the write beam is achieved in that a write beam is focused onto the storage medium and moved one-dimensionally relative to the storage medium, in that a scanning beam is focused onto a trigger mask having a plurality of trigger lines and moved one-dimensionally transversely relative to the trigger lines, the movement of the scanning beam being coupled with the movement of the write beam, in that, during the scanning of the trigger lines, a timed trigger signal is generated as a function of the arrangement of the trigger lines, in that, with the aid of the timed trigger signal, the intensity of the write beam on the storage medium is controlled, and in that the hologram is written line by li

Abstract: The present invention relates to an apparatus for writing to optical storage media capable of performing pre-exposure and/or curing of a photo-sensitive material for optical data storage, in particular for holographic data storage. The apparatus has a first light source for emitting a first light beam, a second light source for emitting a second light beam, and a spatial light modulator, which is switchable between at least two states for spatially modulating at least a part of the first light beam, and which is arranged such that in a first state it directs the first light beam towards an optical storage medium, and that in a second state it directs the second light beam towards the optical storage medium.

Abstract: There is provided a hologram recording medium having: a recording layer at which a hologram can be recorded by illumination of writing light; and a protective layer provided on the recording layer in order to protect the recording layer, a water absorbency of the protective layer being less than or equal to 0.01%.

Abstract: A lithograph for producing digital holograms in a storage medium includes a light source for producing a write beam, the light source having drive means for the two-dimensional movement of the write beam relative to the storage medium and having a first objective for focusing the write beam onto the storage medium. Writing computer-generated holograms by means of optical lithography is solved in that: a two-dimensional trigger matrix is provided, means of producing a scanning beam are provided, a second objective for focusing the scanning beam onto the trigger matrix is provided, the drive means moves the scanning beam two-dimensionally relative to the surface of the trigger matrix, the movement of the scanning beam being coupled with the movement of the write beam, and means for generating a trigger signal to control the intensity of the write beam are connected to the trigger matrix.

Abstract: The present invention relates to materials comprising hydrophilic polymers and immobilized proteorhodopsin and the use of such materials as an optical information carrier. The material comprises one or more hydrophilic polymers that are capable to form a homogeneous phase with proteorhodopsin prior to solidification to a solid form. The hydrophilic polymer, for example, is silica sol-gel, gelatin, polyvinylalcohol, agarose, agar, methyl cellulose, polyvinyl acetate, polyvinyl pyrrolidone, polyethylene glycol, or a mixture thereof. The solid material having immobilized proteorhodopsin is deposited on a substrate selected from the group consisting of glass, paper, metal, fabric material, plastic material, and used as an optical data storage material or a fraud-proof carrier. The present invention further provides a security ink comprising proteorhodopsin and one or more hydrophilic polymers.

Abstract: An object of the present invention is to provide a hologram recording material composition comprising a radical polymerizable compound being solid at an ordinary temperature and having a 9,9-diarylflourene skeleton, a polymeric binder and a plasticizer, the composition being excellent in transparency and diffraction efficiency, which are characteristics required for a hologram. The hologram recording material composition comprises a thermoplastic resin (A) which is soluble in a solvent, a radical polymerizable compound (B) which is solid at an ordinary temperature and at ordinary pressure and has the 9,9-diarylfluorene skeleton and at least one radical polymerizable unsaturated double bond, a plasticizer (C) and a photopolymerization initiator (D). A weight percentage ratio of the thermoplastic resin (A), the radical polymerizable compound (B) and the plasticizer (C), (A):(B):(C) is 10 to 80:10 to 80:10 to 80.

Abstract: The present invention provides methods for storing holographic data and articles derived using these methods. The method includes providing an optically transparent substrate comprising a photochemically active dye and a sensitizing solvent. The method further includes irradiating the optically transparent substrate with a holographic interference pattern to form an optically readable datum and removing at least a portion of the sensitizing solvent from the optically transparent substrate to stabilize the optically readable datum.

Abstract: Photo-thermo-refractive (PTR) glass is a multi-component silicate glass having photosensitivity in rear UV region. A novel process is disclosed for PTR glass sensitization to visible region by means of two-step illumination followed by thermal development. This disclosed process utilizes a first illumination at approximately 325 nm followed by a second illumination with radiation in the visible spectral region out of the region of original photosensitivity of the PTR glass which enables fabrication of complex holographic optical elements for visible region such as plane elements, lenses, curved mirrors, combinations of complex elements and optical correlators. The same process provides a positive increment of refractive index in the bulk of the PTR glass and, therefore, can be used for refractive optical elements recording, such as lenses and waveguides.

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: An optical device generated by interferometric lithography, in the form of a surface relief pattern that diffracts light, to be used mainly in optical security, produced by optical systems compliant with the Schimpflug and hinge Rules containing: two identical lenses L1 and L2, two physical object location B1 e B2 and one image plane A1?A2. No physical mask is needed throughout the origination process, thus eliminating any kind of border effects. The device actually implements an in-plane focused hologram, with a complex surface pattern of valleys and ridges with a non-trivial generating function, which is, by itself, both an additional security feature of the device and its fingerprint. The time to generate the optical device is proportional to the number of colours specified for the reference geometry and not depend on the overall area of the optical device.

Abstract: A holographic recording medium 10 includes: a recording layer 12; two substrates 14 and 16 sandwiching the same; and a photosensitive protective layer 18 covering these recording layer 12 and substrates 14 and 16 entirely. The recording layer 12 is set so that its photosensitivity corresponding to a recording wavelength falls in the vicinity of the recording wavelength from shorter wavelengths to longer wavelengths. The photosensitive protective layer 18 is set so that its light transmittance corresponding to the recording wavelength falls in the vicinity of the recording wavelength from longer wavelengths to shorter wavelengths. This improves damage of the recording layer from ambient exposure without a drop in recording sensitivity.

Abstract: An interference lithography system is described that is capable of exposing high resolution patterns in photosensitive media and employing yield increasing active stabilization techniques needed in production environments. The inventive device utilizes a division-of-wavefront interference lithography configuration which divides a single large field size optical beam using one or more mirrors, and is actively stabilized with a subsystem employing; a phase modulator operating on each divided wavefront section; a novel feedback apparatus for observing the relative phase shifts between interfering wavefront sections; and a control system for holding the relative phase shifts constant.

Abstract: Disclosed is a photopolymerizable holographic recording medium for data storage that comprises colloidal metal, and which exhibits a threshold for a second stage polymerization which is substantially insensitive to the light used for both forming holograms and interrogating the medium during servo and/or read events. Also disclosed is a method of preparing said photopolymerizable holographic recording medium. Also disclosed is a method for preparing a colloidal without additives in a viscous medium.

Abstract: There is provided an optical recording medium comprising a recording layer containing a charge-generating material capable of generating a first electric charge and a second electric charge by beam irradiation, the second electric charge having a different polarity from that of the first electric charge, a charge-transport material enabling at least the first electric charge to be transported to isolate the first electric charge and the second electric charge, and a trapping material retaining the first electric charge. The optical characteristics of the recording layer is changed in accordance with changes in spatial distribution of the first and second electric charges, and the trapping material is provided with a conjugated system and with at least one nitrogen-containing heterocyclic group, and bonded through an unsaturated carbon atom of the heterocyclic group to the conjugated system.

Abstract: A method of writing a spatially heterodyne hologram having spatially heterodyne fringes includes: passing a single write beam through a spatial light modulator that digitally modulates said single write beam; and focusing the single write beam at a focal plane of a lens to impose a holographic diffraction grating pattern on the photorefractive crystal, the holographic diffraction grating pattern including the spatially heterodyne hologram having spatially heterodyne fringes, wherein only said single write beam is incident on said photorefractive crystal without a reference beam.

Abstract: The present invention provides a composition comprising at least one a photoactive index-contrasting polymerizable material, wherein the photoactive polymerizable material comprises at least one reactive functional group and at least one index-contrasting group, and wherein the photoactive polymerizable material includes one or more of the following parameters: (1) a distance between at least one reactive group and at least one index-contrasting group which is at least to the average radius of the index-contrasting group; (2) two or more reactive groups per photoactive polymerizable materials; (3) an index-contrasting group having a strong chromophore absorption at a wavelength shorter than the recording wavelength, and (4) the photoactive polymerizable material comprises a reactive nanoparticle. The photoactive polymerizable material may be used to prepare an article by, for example, dispersion thereof in a support matrix, which may be used, for example, to record holograms.

Abstract: A diffractive optical element is fabricated to have a first element and a second element of different materials bonded to each other with a diffraction grating formed between the elements. In forming the first element, a material thereof is stamped with a die having a diffraction grating pattern. In forming the second element, a photo-setting resin material is deposited on a diffraction grating surface of the first element, stamped with a die, and cured by transmitting light rays through the first element. The first and second elements are made of materials selected such that a transmittance of the first element and a transmittance of said second element are substantially equal to each other for the curing light rays. Differences in cure shrinkage of the photo-setting resin material are thereby controlled within a range so as not to degrade desired performance of the diffractive optical element.

Abstract: A holographic recording medium 1 includes a holographic recording layer 7 having information recorded by use of recording beams L1, L2 and a two-state variable layer 5 arranged on one side of the holographic recording medium 1 where the recording beams L, L2 radiate from the holographic recording layer 7. In the holographic recording medium 1, the two-state variable layer 5 is made from a material whose state can be changed from a first state to a second state by receiving a light and whose reflectivity can be changed from a first reflectivity corresponding to the first state to a second reflectivity corresponding to the second state. The second reflectivity is higher than the first reflectivity.

Abstract: A novel photoimageable system for a two-chemistry system containing liquid photoreactive asymmetric acrylate compound containing sulfur, aromatic moieties, and optionally bromine, and an aluminum salt compound is disclosed. The photoimageable system has high dynamic range (M/#) and sensitivity and unexpectedly high temperature and high humidity resistance. The photoimageable system retains its dynamic range when exposed to 60° C. for 4 weeks while a composition without the aluminum salt compound lost 75% of its dynamic range under similar exposure conditions. In one embodiment, 2-10 weight % of a thio-butylacrylate dissolved in a two-component urethane matrix containing 0.002 to 1 weight % of the aluminum salt compound showed a dynamic range of greater than 5 for a 200 microns thick sample and retained more than 80% of the dynamic range after 4 weeks exposure at 60° C.

Abstract: A holographic recording medium includes a recording layer containing a matrix material, a photoactive monomer having an ethylenic unsaturated bond dispersed in the matrix material and a photoinitiator, and a polymerization-terminating layer formed on at least one surface of the recording layer.

Abstract: A holographic recording medium has a recording layer, including a matrix formed of a polymer of spiroorthoester of an epoxy compound, a radical-polymerizable compound, and a photoinitiator.

Abstract: Fiber optic devices including volume Bragg grating (VBG) elements are disclosed. A fiber optic device may include one or more optical inputs, one or more VBG elements, and one or more optical receivers. Methods for manufacturing VBG elements and for controlling filter response are also disclosed. A VBG chip, and fiber optic devices using such a chip, are also provided. A VBG chip includes a monolithic glass structure onto which a plurality of VBGs have been recorded.

Abstract: Hologram production devices can include holographic recording material deposition systems to deposit holographic recording material as needed by the hologram production device. Various nozzles, ink jets, and similar devices can be used to deposit one or more components of the holographic recording material on to an appropriate substrate. If needed, the material is pre-processed to, for example, provide material stability for the holographic recording material. Once holograms are recorded in the holographic recording material, the material can be post-processed as desired.

Abstract: According to an exemplary embodiment of the present invention, an optical apparatus includes an optical filter array which comprises a plurality of optical filter elements, wherein at least one of the optical filter elements is adapted for tuning to two or more wavelengths. According to another exemplary embodiment of the present invention, an optical apparatus includes a monolithic optical filter array which further includes at least one tunable optical filter element. The optical apparatus also includes a tuning mechanism which tunes the tunable optical filter element to extract a signal of a particular wavelength from an optical signal which includes a plurality of wavelengths. According to another exemplary embodiment of the present invention, a method for selectively extracting optical signals of particular wavelengths includes providing a monolithic optical filter array which further includes at least one tunable optical filter element.

Abstract: A hologram recording material with high sensitivity, high diffraction efficiency, good storability, a small shrinkage ratio, dry processing applicability and a multiple recording performance, which is applicable to high density optical recording media and the like, is provided. The hologram recording material contains the specific acid generator of sensitizing dye.

Abstract: A method for aligning an exposure mask, comprises: using a plurality of hologram masks, on which alignment marks are formed,; aligning position of the hologram masks toward an object, which is exposed and on which alignment marks are also formed, a plurality of times by using both alignment marks, wherein a first straight line connects a first area on the object to be exposed for a pattern exposure with the alignment mark for aligning with a holographic mask that is used in an exposure onto the first area and a second straight line connects the other area, adjacent to the first area, on the object to be exposed for a pattern exposure with the other alignment mark for aligning with a holographic mask that is used in an exposure onto the another area, and the first straight line and the second straight line are intersected each other.

Abstract: Transmission and reflection type holograms may be formed utilizing a novel polymer-dispersed liquid crystal (PDLC) material and its unique switching characteristics to form optical elements. Applications for these switchable holograms include communications switches and switchable transmission, and reflection red, green, and blue lenses. The PDLC material of the present invention offers all of the features of holographic photopolymers with the added advantage that the hologram can be switched on and off with the application of an electric field. The material is a mixture of a polymerizable monomer and liquid crystal, along with other ingredients, including a photoinitiator dye. Upon irradiation, the liquid crystal separates as a distinct phase of nanometer-size droplets aligned in periodic channels forming the hologram. The material is called a holographic polymer-dispersed liquid crystal (H-PDLC).

Abstract: A method for aligning an exposure mask comprises: using a plurality of hologram masks, on which an alignment mark is formed; aligning position of the hologram masks toward an object to be exposed and on which an alignment mark is also formed, with a plurality of times by using both alignment marks; and pattern-exposing the object, wherein, while aligning at least three consecutive times, an alignment mark for third time aligning on the object is set in between alignment marks respectively for second time aligning and first time aligning, or at a position on an opposite side to a side in which the alignment mark for second time aligning is located with respect to the alignment mark for first time aligning.

Abstract: A photopolymerizing composition and a photopolymerizing recording medium manufactured using the composition, wherein the photopolymerizing composition contains: 1.0-99.0% by weight of at least one kind of polymerizable compound; 0.05-0.5% by weight of at least one kind of photosensitizer selected from among photochromic compounds that change color by incoherent UV light irradiation; 0.2-6.0% by weight of a coinitiator that is activated by visible light in the presence of a photoinduced form of the photochromic compound transformed by incoherent UV light to photopolymerize the polymerizable compound; 0-97.5% by weight of a polymer binding agent; 0-6.0% by weight of a plasticizer; and 0-3.0% by weight of a non-polymerizing solvent. The photopolymerizing recording medium has a high angular diffraction selectivity and thus can be effectively used to manufacture a 3D holographic optical memory with ultra high information storage capacity.