A diffractive optical element includes a plurality of diffractive layers. The plurality of diffractive layers includes adjacent diffractive layers including a plurality of optical axes that change along in-plane rotation directions opposite to

A display panel has an array of pixels backlighted by a backlight including a lightguide and a plurality of out-coupling gratings. The locations of the out-coupling gratings are coordinated with positions of pixels in the array of pixels. The backlight may include a light-conducting transparent slab or an array of linear waveguides running parallel to the rows of the pixel array, with the gratings formed in the slab or in the waveguide. Wavelength composition and polarization of the light emitted by the waveguide may be matched to the transmission spectral bands and transmission polarization of the display panel.

An optical waveguide comprises at least two TIR surface and contains a grating. Input TIR light with a first angular range along a first propagation direction undergoes at least two diffractions at the grating. Each diffraction directs light into a unique TIR angular range along a second propagation direction.

In one aspect, an optical device comprises a plurality of waveguides formed over one another and having formed thereon respective diffraction gratings, wherein the respective diffraction gratings are configured to diffract visible light incident thereon into respective waveguides, such that visible light diffracted into the respective waveguides propagates therewithin. The respective diffraction gratings are configured to diffract the visible light into the respective waveguides within respective field of views (FOVs) with respect to layer normal directions of the respective waveguides. The respective FOVs are such that the plurality of waveguides are configured to diffract the visible light within a combined FOV that is continuous and greater than each of the respective FOVs

Disclosed is a polarization separation device to receive an incident light beam. The device includes first and second geometric-phase lenses, having respective first optical centers, first optical axes and first focal lengths. The first and second geometric-phase lenses are separated from one another by a first distance according to the first optical axis, the first geometric-phase lens and the second geometric-phase lens being disposed to have an optical power with the same sign for a first circular polarization state and an optical power with an opposite sign for another circular polarization state orthogonal to the first circular polarization state. The device is configured and directed so a projection of the first optical center according to the first optical axis on the second geometric-phase optical lens is located at a non-zero second distance from the second optical center.

Improved illumination optics for various applications. The illumination optics may include an optical beam spreading structure that provides a large spread angle for an incident collimated beam or provides finer detail or resolution compared to convention diffractive optical elements. The optical beam spreading structure may include first and second spatially varying polarizers that are optically aligned with each other. The first and second spatially varying polarizers may be formed of a liquid crystal material, such as a multi-twist retarder (MTR). The first and second spatially varying polarizers may diffract light of orthogonal polarization states, which allows for different diffraction patterns to be used in a single optical structure. The two patterns may provide a combined field of view that is larger than either of the first and second fields of view or may provide finer detail or resolution than the first or second fields of view can provide alone.

A near eye display (NED) includes multiple PBP optical elements combined with one or more C-plates to improve optical angular performance. The PBP optical elements may be configured for beam steering or for focusing light to a point. A C-plate may reduce or eliminate an undesirable polarization phase shift introduced by the PBP optical elements to angular, off-axis light. Birefringence of the PBP optical elements produces such a polarization phase shift. A C-plate provides an additional polarization phase shift that is opposite to the extra polarization phase shift by the PBP optical elements. Thus, the additional polarization phase shift by the C-plate at least partially reduces the phase shift by the PBP element.

There is provided an illumination device comprising: a laser; a waveguide comprising at least first and second transparent lamina; a first grating device for coupling light from the laser into a TIR path in the waveguide; a second grating device for coupling light from the TIR path out of the waveguide; and a third grating device for applying a variation of at least one of beam deflection, phase retardation or polarization rotation across the wavefronts of the TIR light. The first second and third grating devices are each sandwiched by transparent lamina.

According to one embodiment, a liquid crystal optical element includes a substrate having a first surface, a plurality of structures disposed on the first surface and arranged at a predetermined pitch, and a liquid crystal layer surrounding each of the structures and interposed between the structures adjacent to each other. The liquid crystal layer has a larger thickness than the structure. The liquid crystal layer has liquid crystal molecules arranged along the structure, and is cured in a state in which an alignment direction of the liquid crystal molecules is fixed.

A cycloidal diffractive waveplate based star simulator generates a star field with very high precision star locations and accurate brightness. The present disclosure provides a star simulator that allows for a large FOV, modular, multi-star simulator capable of very high precision dynamic star locations for testing of high accuracy, large FOV star trackers. The system is composed of a light source, a polarization grating-based image [1], and an opto-mechanical system for steering the light. The light is projected onto a diffuse screen where the light is scattered, creating a functional point source at the screen. A star tracker or other device under test views the screen which has a multitude of projected spots (each with its own light source and beam steering device) positioned in a star field distribution appropriate for the simulated viewing direction.