An optical device and an eye-tracking system to suppress a rainbow effect are provided. The optical device includes a grating. The grating includes at least one substrate and a grating structure coupled to the at least one substrate. The grating structure is configured to diffract an infrared light beam and transmit a visible light beam with a diffraction efficiency less than a predetermined threshold.

The present invention discloses a method that combines two different hologram origination processes in a single photoresist layer by using an interlayer to transfer structures exposed by electron beam lithography into overlapped with dot-matrix hologram areas, and fabricated holographic structures are replicated in multilayer polymer films. Dot-matrix technique is low cost process, which has high origination speed and can be used for the patterning of large areas of holograms with high diffraction efficiency. Electron beam lithography allows the formation of high resolution structures. The proposed manufacturing method allows combining these two technologies so that the final security device could contain electron beam patterned high resolution diffraction gratings, computer generated holograms, as well as dot-matrix laser patterned large hologram areas with high diffraction efficiency, providing an increased level of protection.

Provided herein is a process for preparing triaryl organoborates proceeding from alkyl or cycloalkyl boronates in the presence of an n-valent cation 1/n K.sup.n+ to obtain organoborates of the formula 1/n K.sup.n+R.sub.3.sup.4B.sup.−—R.sup.1 (IV), where one equivalent of organoboronic ester of the formula B—R.sup.1(OR.sup.2)(OR.sup.3) (I) is initially charged together with 1/n equivalents of salt K.sup.n+ nX.sup.− (II) and 3 equivalents of metal M in a solvent or a solvent mixture, 3 equivalents of a haloaromatic R.sup.4—Y (III) are added, and optionally a second organic solvent water is added and the compound 1/n K.sup.n+ R.sub.2.sup.4B.sup.−—R.sup.1 (IV) is separated off with the organic phase, and to the use of these substances as co-initiator in photopolymer formulations.

A holographic optical apparatus includes a beam splitting component, a transmission assembly, a focal length modulation component and an optical element. The beam splitting component splits received light into reference light and signal light that are coherent light, and outputs the reference light and the signal light. The focal length modulation component includes a plurality of local length modulation regions with different focal lengths. The optical element includes a recording medium layer with a plurality of recording regions, and each recording region is located in a light-exit path of a focal length modulation region. The transmission assembly is disposed in a light-exit path of the beam splitting component, transmit the reference light to the plurality of recording regions and transmit the signal light to the plurality of focal length modulation regions.

A photopolymer composition comprising a polymer matrix or a precursor thereof including a reaction product between (i) a (meth)acrylate-based (co)polymer in which a silane-based functional group is located in a branched chain and an equivalent weight of the silane-based functional group is 300 g/eq to 2000 g/eq, and (ii) a linear silane crosslinking agent; a photoreactive monomer; and a photoinitiator, a hologram recording medium using the same, an optical element using the hologram recording medium, and a holographic recording method. The photopolymer composition can more easily provide a photopolymer layer having improved durability against temperature and humidity while having a large refractive index modulation value.

The present invention relates to a compound having a novel structure, a photopolymer composition including the compound as a dye, a hologram recording medium produced from the photopolymer composition, an optical element including the hologram recording medium, and a holographic recording method using the hologram recording medium.

The present invention belongs to the field of functional materials, and particularly relates to a directly printable image recording material, a preparation method and application thereof. The image recording material comprises 25 to 78.8 parts by mass of a photopolymerizable monomer, 0.2 to 5 parts by mass of a photoinitiator, 20 to 70 parts by mass of an inert component, and 0.05 to 2 parts by mass of a thermal polymerization inhibitor, and has an initial viscosity of 200 to 800 mPa.Math.s. The photopolymerizable monomer includes a thiol monomer and an olefin monomer, at least one of which is a silicon-based monomer with polyhedral oligomeric silsesquioxane as a silicon core. By introducing a POSS-based thiol or olefin monomer into the photopolymerizable monomer in combination with other material components, the recording material is allowed to have an initial viscosity of 200 to 800 mPa.Math.s, and meanwhile, the low thermal conductivity characteristic of the POSS-based photopolymerizable monomer is utilized, so that image storage quality is ensured, continuous industrial production of the image recording material is achieved, the process cost is reduced and the production efficiency is improved.

The invention relates to a process for producing an optical casting comprising at least one volume-holographic optical element by means of at least one casting operation, the process comprising the following steps: providing a casting mould comprising a first mould section having a flat, spherical, aspherical or free-form first surface and a second mould section having a flat, spherical, aspherical or free-form second surface, the first mould section being connectable to the second mould section to form the casting mould, providing at least one holographic optical element, positioning and aligning the at least one holographic optical element with respect to the first mould section or/and with respect to the second mould section, combining the first and second mould sections to form the casting mould, introducing casting material in one or more casting steps, the casting material having a maximum viscosity at 25° C. of 100 000 mPas, curing the casting material, removing the cured casting material comprising the at least one holographic optical element from the casting mould, the at least one holographic optical element being at least partly surrounded by the casting material.

The disclosure provides recording materials including aromatic substituted ethane-core 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 monomers and polymers for use in Bragg gratings applications, leading to materials with higher refractive index, low birefringence, and high transparency. The disclosed 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.

The disclosure provides recording materials including aromatic substituted methane-core 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 monomers and polymers for use in Bragg gratings applications leading to materials with higher refractive index, low birefringence, and high transparency. The disclosed 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.