A filter device for an optical sensor, including a hologram having a defined number of holographic functions, which are developed in such a way that the filter device blocks optical radiation that impinges upon the filter device from a defined first solid angle and optical radiation that impinges upon the filter device from a defined second solid angle is able to pass through the filter device.

A duplex wideband grating includes a first diffraction element and a second diffraction element. The first diffraction element and the second diffraction element may reside in a single volume or in two separate volumes. The first diffraction element may include a first set of Bragg planes, and the second diffraction element may include a second set of Bragg planes. The first diffraction element may be designed to have a peak diffraction efficiency at a first wavelength, and the second diffraction element may be designed to have a peak diffraction efficiency at a second wavelength different from the first wavelength. The first diffraction element and the second diffraction element may be designed to achieve a same angle of dispersion between wavelengths. The duplex wideband grating may have a broader bandwidth with higher average diffraction efficiency across the broader bandwidth than either the first diffraction element or the second diffraction element.

An imaging system includes a light source configured to produce a plurality of spatially separated light beams. The system also includes an injection optical system configured to modify the plurality of beams, such that respective pupils formed by beams of the plurality exiting from the injection optical system are spatially separated from each other. The system further includes a light-guiding optical element having an in-coupling grating configured to admit a first beam of the plurality into the light-guiding optical element while excluding a second beam of the plurality from the light-guiding optical element, such that the first beam propagates by substantially total internal reflection through the light-guiding optical element.

The present invention features new waveguide layouts for input, redirection (expansion), and output holograms that minimize cross talk between colors and allow all three colors to reside in a single waveguide. The use of multiple incoupling holograms that diffract different colors of light in different directions, or along different paths, through a waveguide substrate advantageously provides for a reduction of cross-talk between the colors of a holographic image. In a square-shaped design, red, green, and blue input and output holograms approximately overlay on top of each other. The green redirection hologram is laterally separated from the red and blue redirection holograms. Using this square-shape design, the light beams for the three colors are separated into two paths propagating from input to output holograms.

A holographic display device includes a display panel for emitting a first image light and a diffraction component on an optical path of the first image light. The first image light includes first and second colors of light. The diffraction component diffracts the first color light at a first diffraction efficiency and diffracts the second color light at a second diffraction efficiency. The first color light and the second color light after diffraction are mixed together in a second image light for generating holographic images. By emitting the first color light and the second color light in the first image light at the same grayscale value, a ratio of intensities of the first color light and the second color light becomes inversely proportional to a ratio of the first diffraction efficiency and the second diffraction efficiency.

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.

Systems and methods for generating multi-layer hologram projections are described. For example, a system generally comprises at least two projection layers in a spaced-apart arrangement; at least one layer-specific projector device associated with each of the at least two projection layers, each layer-specific projector device being configured to project one or more images on an associated projection layer; and a processor coupled to each of the at least one layer-specific projector device, the processor being configured to control each layer-specific projector device to project one or more images on the corresponding projection layer.

A holographic head-up display (HUD) including: a picture generation unit (PGU) including at least one laser light source to generate an optical image to be projected on a HUD; a first mirror to reflect the optical image from the PGU; a second mirror to reflect the optical image reflected by the first mirror; and a holographic optical element (HOE) to diffract the optical image reflected by the second mirror at a first diffraction angle to provide an output optical image in a target direction. The first mirror includes a reflective compensatory HOE to diffract the optical image from the PGU at a second diffraction angle, and in response to change of a wavelength of the optical image from the PGU, the reflective compensatory HOE is configured to diffract the optical image from the PGU at a third diffraction angle different from the second diffraction angle such that the HOE provides the output optical image in the target direction.

A method of operating an AR system to display an image viewable by a user's eyes includes tracking, by an eye-tracking subsystem, a position of the user's eyes and determining, based on the position, a focus depth of the user's eyes. The method also includes selecting, from a plurality of light-guiding optical elements, a subset of light-guiding optical elements configured to focus light at a depth plane corresponding to the focus depth of the user's eyes, producing a plurality of light beams using a subset of sub-light sources of a plurality of sub-light sources, the subset of sub-light sources being configured to illuminate the subset of light-guiding optical elements, and imaging the plurality of light beams through an imaging system and onto the subset of light-guiding optical elements such that the image is generated at the depth plane corresponding to the focus depth of the user's eyes.

The layered generation of at least one volume grating in a recording medium by way of exposure, the recording medium having at least one photosensitive layer which is sensitized for a presettable wavelength of the exposure light. Each volume grating is generated in the recording medium by at least two wave fronts of coherent light capable of generating interference, the wave fronts being superposed in the recording medium at a presettable depth, at a presettable angle and with a presettable interference contrast. The depth and the thickness of the refractive index modulation and/or transparency modulation of a volume grating in the recording medium is controlled by depth-specific control of the spatial and/or temporal degree of coherence of the interfering wave fronts in the direction of light propagation.