A holographic storage layer includes a reflective structure and photosensitive units. The reflective structure is a grid-shaped structure and includes cavities. The photosensitive units are disposed in the cavities, in which each of the photosensitive units is surrounded by the reflective structure. First openings and second openings are defined by the reflective structure, and the photosensitive units are exposed by the first openings and the second openings respectively.

A method for fabricating a holographic blazed grating is provided. The method includes: coating a photoresist layer on a substrate; performing lithography on the photoresist layer to form a photoresist grating; performing vertical ion beam etching on the substrate by using the photoresist grating as a mask, to form a homogeneous grating by transferring a pattern of the photoresist grating onto the substrate; cleaning the substrate to remove remaining photoresist; performing tilted Ar ion beam scanning etching on the substrate by using the homogeneous grating as a mask, and etching different portions of the substrate by utilizing a obscuring effect of the homogeneous grating mask on the ion beam, to form a triangular groove shape of the blazed grating; and cleaning the substrate to obtain the holographic blazed grating.

The subject matter described herein includes a curved VPH grating with tilted fringes and spectrographs, both retroreflective and transmissive, that use such gratings. A VPH grating according to the subject matter described herein includes a first curved surface for receiving light to be diffracted. The grating includes an interior region having tilted fringes to diffract light that passes through the first surface. The grating further includes a second curved surface bounding the interior region on a side opposite the first surface and for passing light diffracted by the fringes.

The present invention provides a visible light photoinitiating system for preparing a holographic photopolymer material with high-diffraction efficiency. The photoinitiating system comprises a photosensitizer and a co-initiator, and its mechanism is that the photosensitizer transforms from ground state to excited state after absorbing photons, and then interacts with the co-initiator through transfer of electrons and protons, which produces an alkyl (or aryl) free radical R and a ketyl radical K; wherein the free radical R initiates the addition polymerization of monomers that are capable of free radical polymerization, whereas the radical K inhibits the chain propagation of the macromolecular free radicals to a certain degree due to the steric hindrance effect, and thus delays the gelation time of the photopolymerization, which helps to increase the phase separation between the polymer and the functional components. A holographic photopolymer material with high-diffraction efficiency can be obtained by employing this visible light photoinitiating system.

A system and method may utilize holography to facilitate fabrication techniques such as 3D printing and lithography. The system may include a light source, a hologram of an original object or lithographic pattern recorded in a holographic medium, and a target such as a reservoir of photosensitive material or a photosensitive material attached to a substrate. Illuminating the hologram with the appropriate light source may cause a holographic image of the original object or lithographic pattern to form on the photosensitive material within the reservoir or on the substrate. Formation of the holographic image may result in the formation of a new object from the photosensitive material, or may facilitate removal or retention of photosensitive material as part of a lithographic process.

Systems, devices, and methods for making, replicating, and using curved holographic optical elements (HOEs) are described. A hologram may be optically recorded into a planar layer of holographic film with various measures in place to compensate for changes (e.g., in optical power and/or playback wavelength and/or angular bandwidth) that may result when a curvature is subsequently applied thereto. A hologram may be optically recorded into a curved layer of holographic film with various measures in place to compensate for optical effects of a curved transparent substrate upon which the holographic film is mounted. A curved HOE may be returned to a planar configuration to undergo holographic replication or holographic replication may be performed using a curved master HOE and curved recipient film. The curved HOEs described herein are particularly well-suited for use when integrated with a curved eyeglass lens to form the transparent combiner of a virtual retina display.

The present invention relates to complex security elements based on recording materials for optical elements with refractive index modulation, in particular, holograms, which are subsequently coated with specific metallic nano-shaped metal particles, a method for their manufacture, in particular on a paper or on a plastic substrate and a security product obtainable using the security element. A further aspect of the invention is the use of such a security element for the prevention of counterfeit or reproduction of a document of value.

A holographic storage layer includes a reflective structure and photosensitive units. The reflective structure is a grid-shaped structure and includes cavities. The photosensitive units are disposed in the cavities, in which each of the photosensitive units is surrounded by the reflective structure. First openings and second openings are defined by the reflective structure, and the photosensitive units are exposed by the first openings and the second openings respectively.

A holographic storage layer includes a reflective structure and photosensitive units. The reflective structure is a grid-shaped structure and includes cavities. The photosensitive units are disposed in the cavities, in which each of the photosensitive units is surrounded by the reflective structure. First openings and second openings are defined by the reflective structure, and the photosensitive units are exposed by the first openings and the second openings respectively.

An aircraft cabin assembly is depicted and described having a cabin wall, which surrounds a cabin interior space and has a wall surface facing the cabin interior space, and having a light source, which is provided in order to emit light onto the wall surface. The problem of providing an aircraft cabin assembly which, irrespective of the light outside of the aircraft cabin assembly, as effectively as possible gives a passenger in the cabin interior space the impression that the cabin interior space is larger than it actually is, is solved in that the wall surface has a holographic image of an object and in that the light source is designed to emit the kind of light onto the wall surface that allows the holographic image to be seen as a three-dimensional image of the object which is the subject of the holographic image.