A head worn imaging system includes a light source configured to generate a light beam. The system also includes a light guiding optical element having a thickness between 0.1 and 1.5 mm and configured to propagate at least a portion of the light beam by total internal reflection. The system further includes an entry portion and an exit portion of the light guiding optical element configured to selectively allow light addressing the exit portion to exit the light guiding optical element based on the angle of incidence of the light, the radius of curvature of the light and/or the wavelength of the light.

An optical assembly includes a partial reflector that is optically coupled with a first polarization volume holographic element. The partial reflector is capable of receiving first light having a first circular polarization and transmitting a portion of the first light having a first circular polarization. The first polarization volume holographic element is configured to receive the first portion of the first light and reflect the first portion of the first light as second light having the first circular polarization. The partial reflector is capable of receiving the second light and reflecting a first portion of the second light as third light having a second circular polarization opposite to the first polarization. The first polarization volume holographic element is configured to receive the third light having the second circular polarization and transmit the third light having the second circular polarization.

A lightguide includes an incoupler configured to receive light emitted from a microdisplay and to direct the received light into the lightguide, a first non-planar major surface and a second non-planar major surface configured to reflect the light directed into the lightguide by the incoupler, and an outcoupler comprising a non-planar, angle selective hologram configured to receive light reflected from at least one of the first major surface and the second major surface and to selectively direct the light out of the lightguide based on the angle of incidence at the hologram.

A head-mounted electronic device may include a display with an optical combiner. The combiner may include a waveguide with first and second output couplers. The first output coupler may couple a first portion of image light at visible wavelengths out of the waveguide and towards an eye box. The second output coupler may couple a second portion of the image light at near-infrared wavelengths out of the waveguide and towards the surrounding environment. The second portion of the image light may include an authentication code that is used by a secondary device to authenticate the head-mounted device and/or may include a pattern that serves to prevent camera equipment in the surrounding environment from capturing accurate facial recognition information from a user while wearing the head-mounted device.

A system includes a plurality of optical identifiers and a reader for the optical identifiers. Each optical identifier has an optical substrate and a volume hologram (e.g., with unique data, such as a code page) in the optical substrate. The reader for the optical identifiers includes an illumination source (e.g., a laser), and a camera. The illumination source is configured to direct light into a selected one of the optical identifiers that has been placed into the reader to produce an image of the associated volume holograms at the camera. The camera is configured to capture the image. The captured image may be stored in a digital format by the system.

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

A method for making an optical grating having a non-uniform refractive index profile along a direction substantially perpendicular to a plane defined by the optical grating includes placing a layer of photopolymerization material having a first surface and a second surface that is opposite to the first surface between a first material transfer layer and a second material transfer layer so that the first surface of the layer of photopolymerization material is in contact with the first material transfer layer and the second surface of the layer of photopolymerization material is in contact with the second material transfer layer to allow material transfer between the layer of photopolymerization material and the first and second material transfer layers by diffusion.

The disclosure provides recording materials including mono- or poly-phenyl-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 mono- or poly-phenyl-core derivatized monomers and polymers for use in Bragg gratings applications, leading to materials with higher refractive index, low birefringence, and high transparency. The disclosed mono- or poly-phenyl-core 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.

Disclosed is a method of generating a volume hologram using a point cloud and a mesh, in which a weight is given to a brightness of a light source according to a direction of a light in order to record a hologram of better quality. The method includes: (a) acquiring multi-view depth and color images; (b) generating point cloud data of a three-dimensional object from the acquired multi-view depth and color images; (c) generating mesh data of the three-dimensional object from the point cloud data of the three-dimensional object; (d) calculating a normal vector of each mesh from the mesh data of the three-dimensional object; (e) extracting three-dimensional data at a user viewpoint from the mesh data of the three-dimensional object by using the normal vector of the mesh; and (f) generating hologram data from three-dimensional data at the user viewpoint.

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.