Abstract: An exemplary compounding method of controlling a compounding device to prepare an admixture of at least two distinct material sources can include examining material source solutions for incompatibility of the ingredients and operating a first and a second pump to prevent one of the incompatible source solutions from entering a common flow path. The processing method can detect degradation of a fluid line by evaluating one or more of calibration error rate data, cumulative volumetric flow data, or cumulative pump operation data. The processing method can also selectively transfer a first group of source solutions using the first pump, receiving pump data from one or more sensors that sense actions of the pumps, applying fluid correction factors and calculating discrete pump movements, the pump movements being indicative of an amount of source solution displacement by a pump, and operating the pumps to selectively dispense the source solution amounts according to a preparation order.

Abstract: A liquid optically clear adhesive (LOCA) for bonding optical substrates includes siloxane and epoxy-containing oligomers, a UV-activated photo-acid generator, a cross-linker additive, a solvent; and a reactive plasticizer, such as an additive of Structure 1. In one example, the additive of Structure 1 constitutes about 1-7% of a total mass of the LOCA excluding the solvent. R1, R2, and R3 of Structure 1 include methoxide, ethoxide, propoxide, or a combination thereof. R4 of Structure 1 includes an alkyl chain that is linear or branched and includes 2-8 carbons. The LOCA material is characterized by a refractive index equal to or greater than about 1.6 at 450 nm and an optical absorption below about 0.1% per micrometer of a thickness of the LOCA material.

Abstract: An optical device with a variable index of refraction is formed by exposing a film to an energy gradient. The optical device has angular selectivity. The optical device can be used as an output coupler for a waveguide used in a virtual-reality and/or augmented-reality apparatus.

Abstract: The disclosure provides recording materials including aromatic substituted alkane-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, including Formula I. When used in Bragg gratings applications, the monomers and polymers disclosed lead to materials with higher refractive index, low birefringence, and high transparency. The disclosed derivatized monomers and polymers 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.

Abstract: Techniques disclosed herein relate to holographic optical materials and elements. An example of a holographic recording material includes matrix monomers characterized by a first refractive index and configured to polymerize to form a polymer matrix, writing monomers dispersed in the matrix monomers and characterized by a second refractive index different from the first refractive index, and a photocatalyst for controlled radical polymerization of the writing monomers. The writing monomers are configured to polymerize upon exposed to recording light. The photocatalyst is dispersed in the matrix monomers. The photocatalyst includes, for example, a transition metal photocatalyst or a metal-free organic photocatalyst, such as a photocatalyst for atom transfer radical polymerization or a transition metal photocatalyst for addition fragmentation chain transfer polymerization.

Abstract: The disclosure provides recording materials include fluorene derivatized monomers and polymers for use in volume Bragg gratings, including, but not limited to, volume Bragg gratings for holography applications. Several fluorene structures are disclosed: simply substituted fluorenes, cardo-fluorenes, and spiro-fluorenes. Fluorene derivatized polymers in Bragg gratings applications lead to materials with higher refractive index, low birefringence, and high transparency. Fluorene derivatized monomers/polymers 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.

Abstract: Gray-tone lithography techniques for controlling the thickness profile of an overcoat layer on a surface-relief grating that has a non-uniform grating parameter (e.g., depth, duty cycle, or period), compensating for the non-uniform etch rate in a large area, defining etch/block regions, and/or controlling the thickness of the grating layer.

Abstract: A method is provided. The method includes forming a shrink material layer over a substrate including a photoresist pattern. The method also includes exposing the substrate with the shrink material layer to an activating radiation via a grey-tone mask that provides a predetermined light transmittance profile for the activating radiation. The method also includes removing at least a portion of the shrink material layer.

Abstract: A grating coupler may be fabricated by exposing a photopolymer layer to grating forming light for forming periodic refractive index variations in the photopolymer layer. The photopolymer layer may be exposed to apodization light for reducing an amplitude of the periodic refractive index variations in a spatially-selective manner. The apodization may also be achieved or facilitated by subjecting outer surface(s) of the photopolymer layer to a chemically reactive agent that causes the refractive index contrast to be reduced near the surface(s) of application. The apodized refractive index profile of the gratings facilitates the reduction of optical crosstalk between different gratings of the grating coupler.

Abstract: The present disclosure relates to systems and methods of making polymeric optical layers for optical layering applications. In an aspect, a waveguide device for a head mounted display is provided. The waveguide device may include a waveguide die having a first refractive index range and a polymeric optical layer. The polymeric optical layer may include a second refractive index range that is different from the first refractive index range and a thiol-containing polymer. For example, the thiol-containing polymer may include thiourethane. In some embodiments, the thiol-containing polymer may be formed from a monomer mixture including a thiol-containing compound and an isocyanate. For example, the thiol-containing compound may include 4-mercaptomethyl-3,6-dithia-1,8-octanedithiol (MDTODT) and/or the isocyanate may include m-xylylene diisocyanate (XDI). In some embodiments, the monomer mixture may include a second thiol-containing compound, such as, for example, 1,3-benzene dithiol (1,3-BDT).

Abstract: Initiator/mediator chemistry for latent imaging polymers for volume Bragg gratings is provided. Light mediated chemistry including the use of nitroxides allows a first step imaging to occur, where a light induced pattern is recorded in the material, without the grating being apparent. A second bleaching/developing step completes the curing process and reveals the grating.

Abstract: A grating coupler may be fabricated by exposing a photopolymer layer to grating forming light for forming periodic refractive index variations in the photopolymer layer. The photopolymer layer may be exposed to apodization light for reducing an amplitude of the periodic refractive index variations in a spatially-selective manner. The apodization may also be achieved or facilitated by subjecting outer surface(s) of the photopolymer layer to a chemically reactive agent that causes the refractive index contrast to be reduced near the surface(s) of application. The apodized refractive index profile of the gratings facilitates the reduction of optical crosstalk between different gratings of the grating coupler.

Abstract: Layered waveguides, multi-layer waveguide displays with layered waveguides, and methods of fabricating layered waveguides with selective bonding material deposition and/or patterning.

Abstract: The disclosure provides recording materials including halogenated 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 halogenated derivatized monomers and polymers for use in Bragg gratings applications, leading to materials with higher refractive index, low birefringence, and high transparency. The disclosed halogenated 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.

Abstract: An optical device includes a substrate, a first surface-relief grating including grooves and ridges formed on or in the substrate, a first overcoat layer in the grooves of the first surface-relief grating, and a first antireflective layer on the first overcoat layer. The ridges of the first surface-relief grating include high-refractive index, photoactive metal oxide nanoparticles and a material of the first overcoat layer in regions between the metal oxide nanoparticles, or the first overcoat layer includes the metal oxide nanoparticles and a material of the first antireflective layer in regions between the metal oxide nanoparticles. Methods of fabricating the optical device are also described.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A method is described for utilizing NIL materials with switchable mechanical properties. The method comprises applying an imprint mask to a nano-imprint lithography (NIL) material layer. The NIL material layer is comprised of a NIL material with a modulus level below a flexibility threshold. The NIL material layer has an internal property, that when changed, causes a change in the modulus level of the NIL material. The method further comprises detaching the imprinted NIL material layer from the imprint mask, with the low modulus level of the NIL material causing a shape of the imprinted NIL material layer to remain unchanged after detachment. A modulus level of the NIL material is increased by changing an internal property of the NIL material, with the modulus level increased beyond a strength threshold to create a first imprint layer that has a structure that remains unaffected by a subsequent process.

Abstract: Techniques disclosed herein relate to modifying refractive index modulation in a holographic optical element, such as a holographic grating. According to certain embodiments, a holographic optical element or apodized grating includes a polymer layer comprising a first region characterized by a first refractive index and a second region characterized by a second refractive index. The holographic optical element or apodized grating includes a plurality of nanoparticles dispersed in the polymer layer. The nanoparticles have a higher concentration in either the first region or the second region. In some embodiments, the nanoparticles may be configured to increase the refractive index modulation. In some embodiments, the nanoparticles may be configured to apodize the grating by decreasing the refractive index modulation proximate to sides of the grating. The refractive index may be modulated by applying a monomer reservoir buffer layer to the polymer layer, either before or after hologram fabrication.