Abstract: An optical reflective device including a waveguide and longitudinal light homogenizing structures mounted to a surface of the waveguide are disclosed. The light homogenizing structures may receive input light and produce longitudinally homogenized light by homogenizing the input light along a longitudinal dimension of the waveguide. A cross-coupler in the waveguide may receive the longitudinally homogenized light from the light homogenizing structures and may produce two-dimensionally homogenized light by redirecting the longitudinally homogenized light along a lateral dimension of the waveguide. The light homogenizing structures may include partially reflective layers, stacked substrate layers with refractive index mismatches, and/or a combination of partially and fully reflective layers. The cross coupler and/or partially reflective layer may be formed using sets of holograms. A prism or a slanted substrate surface may couple the input light into the substrate.

Abstract: A device including a waveguide having a first waveguide surface and a second waveguide surface parallel to the first waveguide surface is disclosed. The device may include a first light coupling device operatively coupled to the waveguide. The first light coupling device may include a first duct structure and a second duct structure oriented to reflect in-coupled light. Each of the first duct structure and the second duct structure may includes a first planar region and a second planar region parallel to the first planar region and a first surface and a second surface parallel to the first surface. The device may also include a second light coupling device disposed between the first waveguide surface and the second waveguide surface. The second light coupling device may be to positioned to receive reflected in-coupled light from the first light coupling device.

Abstract: Systems and methods for performing coherent diffraction in an optical device are disclosed. An optical device may include a grating medium with a first hologram having a first grating frequency. A second hologram at least partially overlapping the first hologram may be provided in the grating medium. The second hologram may have a second grating frequency that is different from the first grating frequency. The first and second holograms may be pair-wise coherent with each other. A manufacturing system may be provided that writes the pair-wise coherent holograms in a grating medium using a signal beam and a reference beam. Periscopes may redirect portions of the signal and reference beams towards a partial reflector, which combines the beams and provides the combined beam to a detector. A controller may adjust an effective path length difference between the signal and reference beams based on a measured interference pattern.

Abstract: A device including a waveguide having a first waveguide surface and a second waveguide surface parallel to the first waveguide surface is disclosed. The device may include a first volume holographic light coupling element disposed between the first waveguide surface and the second waveguide surface. The first volume holographic light coupling element may be structured to reflect at least a portion of incident light as reflected light. Incident light for which the first volume holographic light coupling element is structured to reflect may have a first angle of incidence within a total internal reflection (TIR) range with respect a first axis corresponding to a surface normal of the waveguide. Incident light for which the first volume holographic light coupling element is structured to reflect may have a second angle of incidence with respect to a second axis different from the first axis.

Abstract: A device including a waveguide having a first waveguide surface and a second waveguide surface parallel to the first waveguide surface is disclosed. The device may include a first light coupling device operatively coupled to the waveguide. The first light coupling device may include a first duct structure and a second duct structure oriented to reflect in-coupled light. Each of the first duct structure and the second duct structure may includes a first planar region and a second planar region parallel to the first planar region and a first surface and a second surface parallel to the first surface. The device may also include a second light coupling device disposed between the first waveguide surface and the second waveguide surface. The second light coupling device may be to positioned to receive reflected in-coupled light from the first light coupling device.

Abstract: A method of dispersion compensation in an optical device is disclosed. The method may include identifying a first hologram grating vector of a grating medium of the optical device. The first hologram grating vector may correspond to a first wavelength of light. The method may include determining a probe hologram grating vector corresponding to a second wavelength of light different from the first wavelength of light. The method may also include determining a dispersion-compensated second hologram grating vector based at least in part on the probe hologram grating vector and the first hologram grating vector. A device for reflecting light is disclosed. The device may include a grating medium and a grating structure within the grating medium. The grating medium may include a dispersion compensated hologram.

Abstract: A device including a waveguide having a first waveguide surface and a second waveguide surface parallel to the first waveguide surface is disclosed. The device may include a first volume holographic light coupling element disposed between the first waveguide surface and the second waveguide surface. The first volume holographic light coupling element may be structured to reflect at least a portion of incident light as reflected light. Incident light for which the first volume holographic light coupling element is structured to reflect may have a first angle of incidence within a total internal reflection (TIR) range with respect a first axis corresponding to a surface normal of the waveguide. Incident light for which the first volume holographic light coupling element is structured to reflect may have a second angle of incidence with respect to a second axis different from the first axis.

Abstract: An optical reflective device for pupil equalization including at least one or more grating structures within a grating medium is disclosed. The grating structures may have reflective axes that need not be constrained to surface normal. The grating structures are configured to reflect light about substantially constant reflective axes across a relatively wide range of wavelengths. The optical reflective device may reflect light towards a specific location, such as an exit pupil or eye box. Each grating structure within the device may be configured to reflect light of a particular wavelength at a plurality of incidence angles.

Abstract: An optical reflective device for pupil equalization including at least one or more grating structures within a grating medium is disclosed. The grating structures may have reflective axes that need not be constrained to surface normal. The grating structures are configured to reflect light about substantially constant reflective axes across a relatively wide range of wavelengths. The optical reflective device may reflect light towards a specific location, such as an exit pupil or eye box. Each grating structure within the device may be configured to reflect light of a particular wavelength at a plurality of incidence angles.

Abstract: An optical reflective device for pupil equalization including at least one or more grating structures within a grating medium is disclosed. The grating structures may have reflective axes that need not be constrained to surface normal. The grating structures are configured to reflect light about substantially constant reflective axes across a relatively wide range of wavelengths. The optical reflective device may reflect light towards a specific location, such as an exit pupil or eye box. Each grating structure within the device may be configured to reflect light of a particular wavelength at a plurality of incidence angles.

Abstract: A method of dispersion compensation in an optical device is disclosed. The method may include identifying a first hologram grating vector of a grating medium of the optical device. The first hologram grating vector may correspond to a first wavelength of light. The method may include determining a probe hologram grating vector corresponding to a second wavelength of light different from the first wavelength of light. The method may also include determining a dispersion-compensated second hologram grating vector based at least in part on the probe hologram grating vector and the first hologram grating vector. A device for reflecting light is disclosed. The device may include a grating medium and a grating structure within the grating medium. The grating medium may include a dispersion compensated hologram.

Abstract: An illumination device, which may include a plurality of housing members, a plurality of light emitting elements arranged on each of the housing members, a motor coupled to the housing members to rotate them about a central axis, a sensor system for providing a signal in response to a condition of an area of interest, and control system for controlling the rotational speed of the motor, and selectively energizing the light emitting elements in response to the signal from the sensor, to provide the desired target area with a desired illumination output.

Abstract: An optical reflective device for pupil equalization including at least one or more grating structures within a grating medium is disclosed. The grating structures may have reflective axes that need not be constrained to surface normal. The grating structures are configured to reflect light about substantially constant reflective axes across a relatively wide range of wavelengths. The optical reflective device may reflect light towards a specific location, such as an exit pupil or eye box. Each grating structure within the device may be configured to reflect light of a particular wavelength at a plurality of incidence angles.

Abstract: An optical reflective device for homogenizing light including a waveguide having a first and second waveguide surface and a partially reflective element is disclosed. The partially reflective element may be located between the first waveguide surface and the second waveguide surface. The partially reflective element may have a reflective axis parallel to a waveguide surface normal. The partially reflective element may be configured to reflect light incident on the partially reflective element at a first reflectivity for a first set of incidence angles and reflect light incident on the partially reflective element at a second reflectivity for a second set of incident angles.

Abstract: Optical systems having comb-shifted sets of holograms across different regions of a grating medium are disclosed. A first set of holograms may be formed in a first region of the grating medium and a second set of holograms may be formed in a second region of the grating medium. Each of the holograms in the first set may have a different respective grating frequency from a first set of grating frequencies. Each of the holograms in the second set may have a different respective grating frequency from a second set of grating frequencies. The second set of grating frequencies may be located within adjacent frequency gaps between the grating frequencies in the first set of grating frequencies. Comb-shifted sets of holograms may be used to perform pupil equalization, output coupling, input coupling, cross coupling, or other operations.

Abstract: An optical reflective device including a waveguide and longitudinal light homogenizing structures mounted to a surface of the waveguide are disclosed. The light homogenizing structures may receive input light and produce longitudinally homogenized light by homogenizing the input light along a longitudinal dimension of the waveguide. A cross-coupler in the waveguide may receive the longitudinally homogenized light from the light homogenizing structures and may produce two-dimensionally homogenized light by redirecting the longitudinally homogenized light along a lateral dimension of the waveguide. The light homogenizing structures may include partially reflective layers, stacked substrate layers with refractive index mismatches, and/or a combination of partially and fully reflective layers. The cross coupler and/or partially reflective layer may be formed using sets of holograms. A prism or a slanted substrate surface may couple the input light into the substrate.

Abstract: An optical device for polarizing light including a polarization altering element operatively coupled to a light path associated with the first light coupling device and the second light coupling device is described. The optical device may further include a first waveguide portion including a first layer having parallel plane surfaces with the first waveguide portion having a first light coupling device. The optical device may also include a second waveguide portion including a second layer having parallel plane surfaces with the second waveguide portion having a second light coupling device.

Abstract: A device including a waveguide having a first waveguide surface and a second waveguide surface parallel to the first waveguide surface is disclosed. The device may include a first volume holographic light coupling element disposed between the first waveguide surface and the second waveguide surface. The first volume holographic light coupling element may be structured to reflect at least a portion of incident light as reflected light. Incident light for which the first volume holographic light coupling element is structured to reflect may have a first angle of incidence within a total internal reflection (TIR) range with respect a first axis corresponding to a surface normal of the waveguide. Incident light for which the first volume holographic light coupling element is structured to reflect may have a second angle of incidence with respect to a second axis different from the first axis.

Abstract: Optical systems for performing gaze tracking and imaging an external scene are disclosed. An example optical system may include light sources for emitting visible and non-visible light. The optical system may include a waveguide that is operatively coupled to the light sources. A volume holographic light coupling element may be disposed between the surfaces of the waveguide. The volume holographic light coupling element may include a grating medium and a first volume holographic grating structure within the grating medium. In some examples, the first volume holographic grating structure may be configured to reflect non-visible light of a first wavelength about a first reflective axis offset from a surface normal of the grating medium at a first incidence angle. The optical system may also include an optical filter. Another example optical system may include an imaging device that is configured to receive the light external to the optical system.

Abstract: An optical reflective device for homogenizing light including a waveguide having a first and second waveguide surface and a partially reflective element is disclosed. The partially reflective element may be located between the first waveguide surface and the second waveguide surface. The partially reflective element may have a reflective axis parallel to a waveguide surface normal. The partially reflective element may be configured to reflect light incident on the partially reflective element at a first reflectivity for a first set of incidence angles and reflect light incident on the partially reflective element at a second reflectivity for a second set of incident angles.