Abstract: The invention optical device comprising a self-processing photopolymer material configured to produce a variable two- or three- dimensional diffraction pattern when said material is illuminated by a light source. The invention provides a new material science and process technology which produces a serialisable anti-counterfeit optical device, based on a self-processing photopolymer.

Abstract: A pressure sensitive holographic recording composition is described wherein the composition comprises diacetone acrylamide, glycerol and citric acid. The composition is capable of recording high diffraction efficiency reflection holograms.

Abstract: A pressure sensitive holographic recording composition is described wherein the composition comprises diacetone acrylamide, glycerol and citric acid. The composition is capable of recording high diffraction efficiency reflection holograms.

Abstract: A sensor device comprising a holographic element comprises a grating or hologram recorded in a holographic recording medium wherein at least one physical and/or chemical and/or optical characteristic of the holographic element or the image produced by it varies as a result of variation in relative humidity or moisture content in the air surrounding the element. Also provided is an acrylamide-based photopolymer and an acrylamide-based reflection hologram.

Abstract: The present application provides a method of manufacturing a reflection hologram. The method comprises the steps of placing a first pattern of activating material upon a layer of inactive holographic recording material to selectively activate the layer and exposing the layer to holographic recording process for producing a reflection hologram.

Abstract: We propose a method of detecting the presence of certain chemical and biochemical substances by virtue of the fact that they are, or have attached to them, either a dye molecule which acts as a photosensitizer for a holographic recording process, or another essential molecular component of the holographic recording material such as a monomer or a free radical generator. A recording material used in the process utilizes a photopolymer system consisting of a monomer and a crosslinking monomer, a free radical generator, a photosensitizer and, additionally, a polymeric binder when dry formulations are required and specifically lacks the substance to be detected. Subsequent holographic exposure records an interference pattern only where the complementary substance is present. Applications are broad ranging. Examples in diagnostics, printing, security, and environmental monitoring are given.

Abstract: A sensor device comprising a holographic element comprises a grating or hologram recorded in a holographic recording medium wherein at least one physical and/or chemical and/or optical characteristic of the holographic element or the image produced by it varies as a result of variation in relative humidity or moisture content in the air surrounding the element. Also provided is an acrylamide-based photopolymer and an acrylamide-based reflection hologram.

Abstract: A sensor device comprising a holographic element comprises a grating or hologram recorded in a holographic recording medium wherein at least one physical and/or chemical and/or optical characteristic of the holographic element or the image produced by it varies as a result of variation in relative humidity or moisture content in the air surrounding the element. Also provided is an acrylamide-based photopolymer and an acrylamide-based reflection hologram.

Abstract: A method of recording content comprising the steps of: providing a content storage medium comprising a pre-recorded grating or hologram; and illuminating a pre-recorded grating or hologram with a single recording beam to record content in the grating or hologram. The recording beam may increase the diffraction efficiency of the pre-recorded grating or hologram. Alternatively, the recording beam may form a new grating or hologram in close proximity to a pre-recorded grating or hologram.

Abstract: A multipoint laser Doppler vibrometer system (1) comprises a laser diode (2), beam expanding lens (3), a holographic optical element (HOE, 4) and a CMOS camera (5) receiving reflected light via optics (6). The HOE (4) is a hologram of a flat diffusely reflecting surface. Some light (8) is diffracted by the recorded hologram in the HOE (4) to provide a reference beam of light that is directed back towards the camera (5). Apart from some absorption the remaining light (9) continues onwards to illuminate the object The light that is reflected and scattered from the object (10) passes efficiently through the HOE (4) and interferes with the reference light (8) that is holographically reconstructed by the HOE (4) and subsequently detected by the camera (5). The beam from the laser diode (2) is divergent, which means that the sensitivity vector varies across the field of view.

Abstract: The present application provides a method of manufacturing a reflection hologram. The method comprises the steps of placing a first pattern of activating material upon a layer of inactive holographic recording material to selectively activate the layer and exposing the layer to holographic recording process for producing a reflection hologram.

Abstract: A sensor device comprising a holographic element comprises a grating or hologram recorded in a holographic recording medium wherein at least one physical and/or chemical and/or optical characteristic of the holographic element or the image produced by it varies as a result of variation in relative humidity or moisture content in the air surrounding the element. Also provided is an acrylamide-based photopolymer and an acrylamide-based reflection hologram.

Abstract: We propose a method of detecting the presence of certain chemical and biochemical substances by virtue of the fact that they are, or have attached to them, either a dye molecule which acts as a photosensitizer for a holographic recording process, or another essential molecular component of the holographic recording material such as a monomer or a free radical generator. A recording material used in the process utilizes a photopolymer system consisting of a monomer and a crosslinking monomer, a free radical generator, a photosensitizer and, additionally, a polymeric binder when dry formulations are required and specifically lacks the substance to be detected. Subsequent holographic exposure records an interference pattern only where the complementary substance is present. Applications are broad ranging. Examples in diagnostics, printing, security, and environmental monitoring are given.