A lithographic patterning of a resist is performed to create a mandrel over a substrate. A deposition of one or more functional materials on the mandrel is performed. And each functional material has a respective refractive index. A selective removal of the mandrel is performed to create a plurality of grating elements formed from the one or more functional materials. The plurality of grating elements are self-aligned and form a diffraction grating. Each grating element may have a heterogenous refractive index (e.g., substantial normal to and/or parallel to a surface of the substrate). The diffraction grating may be used in a near-eye display.

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.

The present disclosure relates to a hologram medium comprising: a polymer substrate including a polymer resin in which a silane-based functional group is located in a main chain or a branched chain, wherein a fine pattern is formed on at least one surface of the polymer substrate, and an optical element.

A method of fabricating a refractive optical element on a substrate may provide less expensive and more compact optics for an X-ray system. The method includes coating the substrate with a resin and providing radiation to a portion of the resin to cause two photon polymerization of the resin. The method further includes forming, by two photon polymerization, a first surface of a polymer refractive optical element from the resin. The first surface is disposed along an optical axis of the refractive optical element and the first surface has a roughness of less than 100 nanometers. Further, the method includes forming, by two photon polymerization, a second surface of the polymer refractive optical element. The second surface is disposed along the optical axis of the refractive optical element and the second surface has a roughness of less than 100 nanometers.

Diffractive backlight fabrication employs a diffraction grating to scatter light from a light guide and define a reflective island that is aligned with the diffraction grating. A method of fabricating a diffractive backlight includes providing the light guide having the diffraction grating, diffractively scattering guided light out of the light guide using the diffraction grating to selectively expose photoresist and provide an opening in the photoresist, and depositing a reflective material into the opening to form a reflective island that is aligned with the diffraction grating. A reflective diffraction grating element of the diffractive backlight includes the diffraction grating and reflective island.

Fabricating a diffractive backlight employs a universal grating and selects a portion of the universal grating using a reflective island to define a grating element, a reflective diffraction grating element of the diffractive backlight including the grating element and the reflective island. A method of fabricating a diffractive backlight includes forming the universal grating, forming the reflective island, and selecting a portion of the universal grating using the reflective island to define the grating element. The method of fabricating a diffractive backlight may include forming the reflective island on a light guide surface and forming the universal grating over the reflective island. Alternatively, the method of fabricating a diffractive backlight may include forming the universal grating on the light guide surface and forming the reflective island over the universal grating.

A wavefront sensor includes a mask and a sensor utilized to capture a diffraction pattern generated by light incident to the mask. A reference image is captured in response to a plane wavefront incident on the mask, and another measurement image is captured in response to a distorted wavefront incident on the mask. The distorted wavefront is reconstructed based on differences between the reference image and the measurement image.

A diffractive optical element may include sub-wavelength period stack-and-gap structured layers providing transmissive phase delay at a wavelength. The sub-wavelength period stack-and-gap structured layers may include a set of thin anti-reflection layers that are index matched to an environment or a substrate over a range of fill factors of the sub-wavelength period.

The present disclosure relates to a photopolymer composition including: a polymer matrix or a precursor thereof; a photoreactive monomer including a polyfunctional (meth)acrylate monomer having a refractive index of 1.5 or less and a viscosity at 25° C. of 100 cps or less, and a monofunctional (meth)acrylate monomer having a refractive index of 1.5 or more; and a photoinitiator, wherein a content of the monofunctional (meth)acrylate monomer having a refractive index of 1.5 or more in the photoreactive monomer is 60 wt % or more. The present disclosure also relates to a hologram recording medium produced from the photopolymer composition, an optical element including the hologram recording medium, and a holographic recording method using the photopolymer composition.

A wavefront sensor includes a mask and a sensor utilized to capture a diffraction pattern generated by light incident to the mask. A reference image is captured in response to a plane wavefront incident on the mask, and another measurement image is captured in response to a distorted wavefront incident on the mask. The distorted wavefront is reconstructed based on differences between the reference image and the measurement image.