Abstract: A dual-mode switchable liquid-crystal window can control both radiant energy flow and privacy. The modes are selected by using different voltage frequencies. A dichroic dye is doped to enable modulation of transmission of the window. In the absence of an applied voltage, the window is transparent without haze. When a high-frequency (e.g., 1 kHz) voltage is applied, the liquid crystal and doped dye molecules inside the window reorient uniformly under dielectric interactions. The material becomes optically absorbing. The transmittance decreases, but the haze does not change. In this mode, the window can control radiant energy flow through the window. When a low-frequency (50 Hz) voltage is applied, the liquid crystal and doped dye molecules are switched into a micron-sized polydomain structure under flexoelectric interactions. The material becomes optically scattering and absorbing. The scenery behind the window is blocked. In this mode, privacy can be controlled.

Abstract: A device includes a display configured to generate an image light. The device also includes a waveguide optically coupled with the display and configured to guide the image light to an exit pupil of the device. The waveguide includes a grating including a birefringent material, and a birefringence of the grating is configured to increase along a pupil-expanding direction of the device.

Abstract: A dual-mode switchable liquid-crystal window can control both radiant energy flow and privacy. The modes are selected by using different voltage frequencies. A dichroic dye is doped to enable modulation of transmission of the window. In the absence of an applied voltage, the window is transparent without haze. When a high-frequency (e.g., 1 kHz) voltage is applied, the liquid crystal and doped dye molecules inside the window reorient uniformly under dielectric interactions. The material becomes optically absorbing. The transmittance decreases, but the haze does not change. In this mode, the window can control radiant energy flow through the window. When a low-frequency (50 Hz) voltage is applied, the liquid crystal and doped dye molecules are switched into a micron-sized polydomain structure under flexoelectric interactions. The material becomes optically scattering and absorbing. The scenery behind the window is blocked. In this mode, privacy can be controlled.

Abstract: A dual-mode switchable liquid-crystal window can control both radiant energy flow and privacy. The modes are selected by using different voltage frequencies. A dichroic dye is doped to enable modulation of transmission of the window. In the absence of an applied voltage, the window is transparent without haze. When a high-frequency (e.g., 1 kHz) voltage is applied, the liquid crystal and doped dye molecules inside the window reorient uniformly under dielectric interactions. The material becomes optically absorbing. The transmittance decreases, but the haze does not change. In this mode, the window can control radiant energy flow through the window. When a low-frequency (50 Hz) voltage is applied, the liquid crystal and doped dye molecules are switched into a micron-sized polydomain structure under flexoelectric interactions. The material becomes optically scattering and absorbing. The scenery behind the window is blocked. In this mode, privacy can be controlled.

Abstract: Techniques disclosed herein relate to a near-eye display system. One example of an eye-tracking system includes a substrate transparent to visible light and infrared light and a reflective holographic grating conformally coupled to a surface of the substrate. The reflective holographic grating is configured to transmit the visible light and reflectively diffract infrared light in a first wavelength range for eye tracking. The refractive index modulation of the reflective holographic grating is apodized in a direction along a thickness of the reflective holographic grating to reduce optical artifacts in the visible light.

Abstract: An optical assembly may include a waveguide and a Bragg grating configured to couple light into or out of the waveguide. The Bragg grating may include a plurality of layer pairs, wherein at least one layer pair comprises a first material having a first refractive index and a second layer having a second refractive index, and wherein properties of the Bragg grating are selected so that the Bragg grating exhibits a substantially similar diffractive efficiency and diffraction angle for light of at least two colors.

Abstract: An optical element is provided. The optical element includes a positive-C film including a liquid crystal (“LC”) layer. The optical element also includes a positive-A film. The optical element also includes a negative biaxial retardation film disposed between the positive-A film and the positive-C film.

Abstract: A device includes a display configured to generate an image light. The device also includes a waveguide optically coupled with the display and configured to guide the image light to an exit pupil of the device. The waveguide includes a grating including a birefringent material, and a birefringence of the grating is configured to increase along a pupil-expanding direction of the device.

Abstract: A conventional liquid crystal lens switches on and off so slowly that a person can perceive the lens's gradual transition from high to low optical power. This makes a conventional liquid crystal lens unsuitable for focusing virtual images quickly in an augmented, mixed, or virtual reality system. Conversely, an inventive fast-switching electroactive lens system can switch so fast (e.g., in 35 milliseconds or less) that a person perceives its optical power to change instantaneously. The system accomplishes this fast switching with using an electroactive wave plate in series with slower liquid-crystal lenses. The wave place can be switched quickly between emitting vertically or horizontally polarized light. Each lens focuses either vertically or horizontally polarized light and transmits orthogonally polarized light. By switching between polarization states, the wave plate effectively turns one lens on and the other lens off much faster than either lens could be switched by itself.

Abstract: An optical device includes a display configured to generate an image light; and a waveguide optically coupled with the display and configured to guide the image light to an exit pupil of the optical device. The waveguide includes an in-coupling element configured to couple the image light into the waveguide, and an out-coupling element configured to decouple the image light out of the waveguide. The out-coupling element includes a grating having a diffraction efficiency gradient along a predetermined direction at a plane of the grating.

Abstract: A liquid crystal (LC) mixture for a pitch variable optical element is provided. The LC mixture includes a host LC and one or more LC dimers dissolved as a guest in the host LC. The host LC and the one or more LC dimers have respective dielectric anisotropies of opposite signs in nematic phase. A net dielectric anisotropy of the LC mixture is substantially neutral.

Abstract: A tunable liquid crystal (LC) device includes an LC layer between a pair of reflectors forming an optical cavity. The reflectors include conductive layers for applying an electrical signal to the LC layer. One of the conductive layers may include an array of conductive pixels for spatially selective control of the effective refractive index of the LC layer. The phase delay introduced by the LC layer may be greatly increased or magnified by placing the LC layer into the optical cavity. This enables a substantial reduction of the LC layer thickness, which in its turn enables very tight pitches of the LC pixels, with a reduced inter-pixel crosstalk caused by fringing electric fields, as well as faster switching times. A tight-pitch, fast LC device may be used as a configurable hologram or a spatial light modulator.

Abstract: A tunable liquid crystal (LC) device includes an LC layer between a pair of reflectors forming an optical cavity. The reflectors include conductive layers for applying an electrical signal to the LC layer. One of the conductive layers may include an array of conductive pixels for spatially selective control of the effective refractive index of the LC layer. The phase delay introduced by the LC layer may be greatly increased or magnified by placing the LC layer into the optical cavity. This enables a substantial reduction of the LC layer thickness, which in its turn enables very tight pitches of the LC pixels, with a reduced inter-pixel crosstalk caused by fringing electric fields, as well as faster switching times. A tight-pitch, fast LC device may be used as a configurable hologram or a spatial light modulator.

Abstract: Techniques disclosed herein relate to a near-eye display system. One example of an optical device of a near-eye display includes a substrate and holographic grating conformally coupled to a surface of the substrate. The substrate is transparent to visible light and infrared light and is configured to be placed in front of an eye of a user of the near-eye display. A refractive index modulation of the holographic grating is apodized in a surface-normal direction of the substrate to reduce optical artifacts in the visible light.

Abstract: An optical element is provided. The optical element includes a positive-C film including a liquid crystal (“LC”) layer. The optical element also includes a positive-A film. The optical element also includes a negative biaxial retardation film disposed between the positive-A film and the positive-C film.

Abstract: A liquid crystal (LC) mixture for a pitch variable optical element is provided. The LC mixture includes a host LC and one or more LC dimers dissolved as a guest in the host LC. The host LC and the one or more LC dimers have respective dielectric anisotropies of opposite signs in nematic phase. A net dielectric anisotropy of the LC mixture is substantially neutral.

Abstract: An optical assembly may include a waveguide and a Bragg grating configured to couple light into or out of the waveguide. The Bragg grating may include a plurality of layer pairs, wherein at least one layer pair comprises a first material having a first refractive index and a second layer having a second refractive index, and wherein properties of the Bragg grating are selected so that the Bragg grating exhibits a substantially similar diffractive efficiency and diffraction angle for light of at least two colors.

Abstract: An optical waveplate is provided. The optical waveplate includes a positive-C film including a first liquid crystal (“LC”) layer. Tilt angles of LC molecules vary along a thickness direction of the first LC layer. The optical wave also includes an LC cell disposed at a first side of the positive-C film and including a second LC layer aligned in an optically compensated bend (“OCB”) mode. The optical waveplate also includes a positive-A film disposed at a second side of the positive-C film. The optical waveplate further includes a negative biaxial retardation film disposed between the positive-A film and the positive-C film. The LC cell is switchable between at least two predetermined states.

Abstract: Techniques disclosed herein relate to a near-eye display system. One example of an optical device of a near-eye display includes a substrate and holographic grating conformally coupled to a surface of the substrate. The substrate is transparent to visible light and infrared light and is configured to be placed in front of an eye of a user of the near-eye display. A refractive index modulation of the holographic grating is apodized in a surface-normal direction of the substrate to reduce optical artifacts in the visible light.

Abstract: Techniques disclosed herein relate to a near-eye display system. One example of an eye-tracking system includes a substrate transparent to visible light and infrared light and a reflective holographic grating conformally coupled to a surface of the substrate. The reflective holographic grating is configured to transmit the visible light and reflectively diffract infrared light in a first wavelength range for eye tracking. The refractive index modulation of the reflective holographic grating is apodized in a direction along a thickness of the reflective holographic grating to reduce optical artifacts in the visible light.