A method of recording multiple holograms into a holographic recording medium includes exposing the medium to a first light to cause changes in a first refractive index of at least a portion of a first layer of the medium to write a first hologram in the first layer without changing a second refractive index of a second layer of the recording medium. The method also includes exposing the medium to a second light to cause changes in a second refractive index of at least a portion of the second layer to write a second hologram in the second layer. The first layer may include a first photo-polymerizable composition polymerizable by the first light, and the second layer may include a second photo-polymerizable composition polymerizable by the second light and not polymerizable by the first light.

Provided is a photopolymer composition for hologram recording comprising: a polymer matrix or a precursor thereof; a dye including a compound of the following Chemical Formula 1; a photoreactive monomer; and a photoinitiator, ##STR00001##

Architecture and designs of modulating both amplitude and phase at the same time in spatial light modulation are described. According to one aspect of the present invention, nano-imprinting lithograph (NIL) and E-beam are used to create micro structures (transparent) as alignment cells. A first group of the alignment cells are oriented in a first direction and a second group of the alignment cells are oriented in a second direction, light going through the first group of the alignment cells is modulated in amplitude thereof and the light going through the second group of the alignment cells is modulated in phase thereof, all via the liquid crystals and at the same time.

A holographic recording medium composition contains an isocyanate group-containing compound (component (a-1)), an isocyanate-reactive functional group-containing compound (component (b-1)), a polymerizable monomer (component (c-1)), a photopolymerization initiator (component (d-1)), and a stable nitroxyl radical group-containing compound (component (e-1)). A ratio of the total weight of a propylene glycol unit and a tetramethylene glycol unit that are contained in the component (b-1) to the total weight of the component (a-1) and the component (b-1) is 30% or less.

A system for making a holographic medium for use in generating light patterns for eye tracking includes a light source configured to provide light and a beam splitter configured to separate the light into a first portion of the light and a second portion of the light that is spatially separated from the first portion of the light. The system also includes a first set of optical elements configured to transmit the first portion of the light for providing a first wide-field beam onto an optically recordable medium and one or more diffractive optical elements configured to receive the second portion of the light and project a plurality of separate light patterns onto the optically recordable medium for forming the holographic medium.

Systems and methods for fabricating optical elements in accordance with various embodiments of the invention are illustrated. One embodiment includes a method for fabricating an optical element, the method including providing a first optical substrate, depositing a first layer of a first optical recording material onto the first optical substrate, applying an optical exposure process to the first layer to form a first optical structure, temporarily erasing the first optical structure, depositing a second layer of a second optical recording material, and applying an optical exposure process to the second layer to form a second optical structure, wherein the optical exposure process includes using at least one light beam traversing the first layer.

An embodiment of the present disclosure provides a holographic optical element and a manufacturing method of a holographic optical element including holographic gratings, the manufacturing method including: a step (a) of forming a photosensitive substrate by coating one surface of a substrate with a photosensitive resin; and a step (b) of recording the holographic gratings by irradiating each of one surface and the other surface of the photosensitive substrate with laser light, wherein in the step (a), the photosensitive resin is applied so that a height of a photosensitive resin coating layer varies along a predetermined direction.

Recording a volume Bragg grating is effectuated by a recording medium formed from a matrix polymer precursor including a controlled radical reactive group, a photoactive base monomer, and a photoinitiator system more reactive with the photoactive base monomer than the controlled radical reactive group in the presence of an excitation source, and a photoredox catalyst. The medium is cured thereby forming a support matrix from the matrix polymer precursor. Exposure to the excitation source through a pattern causes the photoinitiator to polymerize the base monomer, forming a latent grating of the Bragg grating. The latent grating has bright and dark fringes determined by the pattern. The concentration of polymerized base polymer is higher in the bright fringes than in the dark fringes. The exposing causes a portion of the matrix to diffuse into the dark fringes. The support matrix has a lower refractive index than the polymerized photoactive base monomer.

Methods of recording a volume Bragg grating are provided. A recording medium is formed from a matrix polymer precursor, an inimer comprising a polymerizable functional group and a controlled radical reactive group, a first photoinitiator system that is more reactive with the polymerizable functional group than the controlled radical reactive group in the presence of an excitation source, and a photoredox catalyst. The medium is cured thereby forming a support matrix. The medium is exposed to light causing the first photoinitiator system to react with the polymerizable functional group and to polymerize the inimer within the support matrix thus forming a latent grating image of the volume Bragg grating within the medium. The latent grating image comprises a plurality of bright fringes and a plurality of dark fringes. A concentration of polymerized inimer is higher in the plurality of bright fringes than in the plurality of dark fringes.

A compound represented by the following formula (1):

##STR00001##

[wherein R.sup.1 represents a hydrogen atom or a methyl group; R.sup.2 represents an aromatic ring group optionally having a substituent or an alkyl group substituted with an aromatic ring group optionally having a substituent; X.sup.1 represents a (thio)ester bond, a (thio)carbonate bond, a (thio)amide bond, a (thio)urethane bond, a (thio)urea bond, a (thio)ether bond, oxygen, sulfur, or a nitrogen atom optionally having a substituent; X.sup.2 represents oxygen, sulfur, or a nitrogen atom optionally having a substituent; A represents a divalent group optionally having a substituent; L represents an (m+1)-valent linking group optionally having a substituent; m represents an integer of 1 to 3; and n represents 0 or 1].