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.

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.

Improvements to gratings for use in waveguides and methods of producing them are described herein. Deep surface relief gratings (SRGs) may offer many advantages over conventional SRGs, an important one being a higher S-diffraction efficiency. In one embodiment, deep SRGs can be implemented as polymer surface relief gratings or evacuated periodic structures (EPSs). EPSs can be formed by first recording a holographic polymer dispersed liquid crystal (HPDLC) periodic structure. Removing the liquid crystal from the cured periodic structure provides a polymer surface relief grating. Polymer surface relief gratings have many applications including for use in waveguide-based displays.

Improvements to gratings for use in waveguides and methods of producing them are described herein. Deep surface relief gratings (SRGs) may offer many advantages over conventional SRGs, an important one being a higher S-diffraction efficiency. In one embodiment, deep SRGs can be implemented as polymer surface relief gratings or evacuated periodic structures (EPSs). EPSs can be formed by first recording a holographic polymer dispersed liquid crystal (HPDLC) periodic structure. Removing the liquid crystal from the cured periodic structure provides a polymer surface relief grating. Polymer surface relief gratings have many applications including for use in waveguide-based displays.

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].

A multifunctional liquid crystalline photoreactive polymer in which at least some of the polymer side-chains have an ultraviolet photoreactive moiety and at least some of the polymer side-chains have a calamitic mesogenic moiety are provided. At least some of the polymer side-chains have a photo-curable moiety a thermal-curable moiety. In some embodiments, the polymer is in the form of a co-polymer. In some embodiments, the polymer is in the form of a ter-polymer. The polymer is used in applications that require stable birefringement films. Such films are produced from the polymer by subjecting the polymer to ultra-violet light to cause side-chain cross-linking thereby inducing anisotropy. The anisotropy is then amplified by exposing the polymer to an elevated temperature.

Methods of recording volume Bragg gratings are provided. A recording medium includes matrix polymer precursor, inimer comprising a polymerizable functional group and a controlled radical reactive group, photoinitiator more reactive with the polymerizable functional group than the controlled radical reactive group in the presence of an excitation source, and a photoredux catalyst. The medium is cured to form a support matrix. The medium is exposed to the excitation source, forming a latent grating having bright fringes and dark fringes. Polymerized inimer is more concentrated in the bright fringes than in the dark fringes. A high refractive index monomer reactive with the controlled radical reactive group is diffused into the medium and exposed to light to cause controlled radical polymerization between the high refractive index monomer and the controlled radical reactive group of the polymerized inimer, driving up a refractive index of the bright fringes relative to the dark fringes.

A photopolymerizable composition including: a polymer matrix or a precursor thereof containing a reaction product of an acrylate-based polyol and a compound containing at least one isocyanate group; a photoreactive monomer; and a non-reactive fluoro compound and a photoinitiator; a hologram recording medium produced from the composition; an optical element including the hologram recording medium; and a method of recording a hologram using the photopolymerizable composition.

To provide a hologram recording composition capable of further improving diffraction characteristics.

The present technology provides a hologram recording composition containing at least a radically polymerizable monomer, a matrix resin, a photopolymerization initiator, and an anthracene-based compound. The present technology also provides a hologram recording medium including a photocurable resin layer containing at least a radically polymerizable monomer, a matrix resin, a photopolymerization initiator, and an anthracene-based compound. Furthermore, the present technology also provides a hologram using the hologram recording medium. Moreover, the present technology also provides an optical device and an optical component using the hologram.