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 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 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: 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: An optical device including a first layer of a total internal reflection (TIR) waveguide and a second layer of the TIR waveguide is disclosed. The second layer of the TIR waveguide may be coupled to the first layer. The second layer may include an output coupling device configured to reflect light toward an exit face of the TIR waveguide. The output coupling device may include one or more diffractive gratings. The optical device may also include an input coupling face disposed on a non-diffractive edge portion the first layer or the second layer or both the first and second layer. The input coupling face may be configured to receive image light. Another optical device may include an input coupling face disposed on a non-diffractive input coupling element. The non-diffractive input coupling element may be positioned in an optical path for directing the image light to the TIR waveguide.

Abstract: An optical device including a first layer of a total internal reflection (TIR) waveguide and a second layer of the TIR waveguide is disclosed. The second layer of the TIR waveguide may be coupled to the first layer. The second layer may include an output coupling device configured to reflect light toward an exit face of the TIR waveguide. The output coupling device may include one or more diffractive gratings. The optical device may also include an input coupling face disposed on a non-diffractive edge portion the first layer or the second layer or both the first and second layer. The input coupling face may be configured to receive image light. Another optical device may include an input coupling face disposed on a non-diffractive input coupling element. The non-diffractive input coupling element may be positioned in an optical path for directing the image light to the TIR waveguide.

Abstract: A skew mirror is an optical reflective device, such as a volume holographic optical element, whose reflective axis forms an angle (the skew angle) with the surface normal. A skew illuminator is a skew mirror that expands a narrow beam into a wide beam without changing the angular bandwidth of the illumination. Because the skew angle can form a relatively large angle with the surface normal (e.g., about 45), a skew illuminator can be fairly compact, making it suitable for directing light onto a spatial light modulator (SLM) in a small package. In some cases, the skew illuminator is formed as a waveguide, with a holographic layer sandwiched between a pair of substrates. A grating structure in the holographic core diffracts light out of the waveguide and, e.g., onto the active area of an SLM, which modulates the incident light and either transmits it or reflects it back through the waveguided skew illuminator.

Abstract: A skew mirror is an optical reflective device whose reflective axis forms a non-zero angle with the surface normal. A spatially varying skew mirror is a skew mirror whose reflective axes vary as a function of lateral position. If a spatially varying skew mirror was subdivided into many pieces, some or all of the many pieces could have a reflective axis that points in a different direction. In some variations, a spatially varying skew mirror can act as a focusing mirror that focuses incident light. A spatially varying skew mirror can be made by recording interference patterns between a phase-modulated writing beam and another writing beam or by recording interference patterns between planar wavefronts in a curved holographic recording medium that is later bent or warped.

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 system and method making one or more holographic optical elements is disclosed. The method may include at least partially submerging a recording medium in an index matching fluid residing in a fluid reservoir. A first surface of the fluid reservoir may include a surface of a first optical coupling element. The method may include positioning the recording medium with respect to the surface of the first optical coupling element. The method may also include applying a first recording beam through the first optical coupling element, the index matching fluid, and a first portion of the recording medium to form a hologram in the first portion of the recording medium.

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: A combination LED lighting system and angle power strip including an elongated and horizontally extending housing which may be placed on a vertical wall below a cabinet or the like. The housing has an inclined front wall which has a plurality of electrical outlets mounted thereon at an acute angle with respect to the wall. The housing also has a lens selectively removably secured thereto which is positioned above the electrical outlets. A LED lighting system is mounted in the housing for directing light downwardly and outwardly through the lens. The ends of the housing have caps removably secured thereto. The housing also has an outer wall member which may be selectively detached from the housing for repair or replacement of the components within the housing.

Abstract: A holographic skew mirror has a reflective axis, or skew axis, that can be tilted with respect to its surface normal. Tilting the skew axis in two dimensions with respect to the surface normal expands the holographic skew mirror's possible field of view, e.g., to 60 or more. These additional angles can be accessed using an out-of-plane writing geometry with matched total internal grazing extension rotation (TIGER) prisms.

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: Electrical outlet plug strips are positioned at the underside of a kitchen cabinet or cabinets. The plug strips include covers which are designed to shield or cover the gaps between adjacent plug strips and to shield or cover support members positioned at the bottoms of adjacent cabinets.