A method for producing holograms with a multiplicity of holographic prescriptions from a single master is provided. A multiplicity of holographic substrates each containing a first hologram is stacked on a second holographic recording medium substrate. The first hologram is designed to diffract light from a first direction into a second direction. When expose to illumination from the first direction zero order and diffracted light from each first hologram interfere in the second holographic recording medium substrate forming a second hologram. The second hologram is then copied into a third holographic recording medium substrate to provide the final copy hologram.

The present invention provides a novel photopolymer formulation comprising matrix polymers, writing monomer and a photoinitiator and further comprising a compound of formula (1) ##STR00001##
where A.sup.1, A.sup.2 and A.sup.3 are each independently hydrogen, fluorine, chlorine, bromine or iodine, R.sup.1, R.sup.2, R.sup.3, R.sup.4 and R.sup.5 are each independently hydrogen, halogen, cyano, nitro, amino, alkylimino, azide, isonitrile, enamino, formyl, acyl, carboxyl, carboxylate, carboxamide, orthoester, sulphonate, phosphate, organosulphonyl, organosulphoxidyl, optionally fluorinated alkoxy or an optionally substituted aromatic, heteroaromatic, aliphatic, araliphatic, olefinic or acetylenic radical while suitable radicals may be connected together via bridge of any desired substitution, or in that two or more compounds of formula (I) may be connected together via at least one of the radicals R.sup.1, R.sup.2, R.sup.3, R.sup.4 and R.sup.5, in which case these radicals therein constitute a 2- to 4-tuply functional bridge, with the proviso that at least one of the radicals R.sup.1, R.sup.2, R.sup.3, R.sup.4 and R.sup.5 is not hydrogen. Further subjects of the invention are a photopolymer comprising matrix polymers, a writing monomer and photoinitiator, a holographic medium comprising a photopolymer formulation of the present invention or being obtainable by use thereof, the use of a holographic medium of the present invention and also a process for producing a holographic medium by using a photopolymer formulation of the present invention.

To provide a photosensitive composition for hologram recording that enables further improvement in diffraction characteristic. A photosensitive composition for hologram recording that includes at least two kinds of photopolymerizable monomers, a photopolymerization initiator, a binder resin, and a polymerization inhibitor. The at least two kinds of photopolymerizable monomers are a monofunctional monomer and a polyfunctional monomer.

The invention relates to a photopolymer formulation comprising a polyol component, a polyisocyanate component, a writing monomer, and a photoinitiator, containing a coinitiator and a dye having the formula F An, where F stands for a cationic dye and An″ stands for an anion, wherein the dye having the formula F An comprises a water absorption of =5%. The invention further relates to a holographic medium, in particular in the form of a film, containing a photopolymer formulation according to the invention, to the use of such a medium for recording holograms, and to a special dye that can be used in the photopolymer formulation according to the invention.

Interlayers that exhibit superior properties and that provide desirable optical properties when incorporated into laminates, such as windshields, windows or other glazings containing a holographic optical element (HOE) are disclosed. The interlayers, when used in a laminate in conjunction with the HOE film, maintain and do not detract from the HOE film properties.

An illumination device (10) includes: laser light sources (20) having different radiant fluxes; and diffractive optical elements (40) provided correspondingly to the respective laser light sources. A planar dimension of the diffractive optical element, which corresponds to the laser light source that emits a laser light having a minimum radiant flux, is smaller than a planar dimension of the diffractive optical element, which corresponds to the laser light source that emits a laser light having a maximum radiant flux.

An optical waveguide is provided. The optical waveguide includes a base structure and a plurality of grating structures disposed at the base structure. The grating structures include a plurality of in-coupling grating structures configured to couple a plurality of lights into the optical waveguide. At least one of a grating period or a slant angle of a first in-coupling grating structure is different from at least one of a corresponding grating period or a corresponding slant angle of a second in-coupling grating structure. The grating structures also include a plurality of out-coupling grating structures configured to couple the lights out of the optical waveguide.

An illumination device includes: laser light sources having different radiant fluxes; and diffractive optical elements provided correspondingly to the respective laser light sources. A planar dimension of the diffractive optical element, which corresponds to the laser light source that emits a laser light having a minimum radiant flux, is smaller than a planar dimension of the diffractive optical element, which corresponds to the laser light source that emits a laser light having a maximum radiant flux.

The disclosure provides recording materials including propane derivatized monomers and polymers for use in volume Bragg gratings, including, but not limited to, volume Bragg gratings for holography applications. Several structures are disclosed for propane derivatized monomers and polymers for use in Bragg gratings applications, leading to materials with higher refractive index, low birefringence, and high transparency. The disclosed propane derivatized monomers and polymers thereof can be used in any volume Bragg gratings materials, including two-stage polymer materials where a matrix is cured in a first step, and then the volume Bragg grating is written by way of a second curing step of a monomer.

A method for making an optical grating having a non-uniform refractive index profile along a direction substantially perpendicular to a plane defined by the optical grating includes placing a layer of photopolymerization material having a first surface and a second surface that is opposite to the first surface between a first material transfer layer and a second material transfer layer so that the first surface of the layer of photopolymerization material is in contact with the first material transfer layer and the second surface of the layer of photopolymerization material is in contact with the second material transfer layer to allow material transfer between the layer of photopolymerization material and the first and second material transfer layers by diffusion.