A system is provided. The system includes a light source configured to emit an infrared light to illuminate an eye of a user. The system includes a grating disposed facing the eye and including a birefringent material film configured with a uniform birefringence lower than or equal to 0.1. The grating is configured to diffract the infrared light reflected from the eye, and transmit a visible light from a real world environment toward the eye, with a diffraction efficiency less than a predetermined threshold. The system includes an optical sensor configured to receive the diffracted infrared light and generate an image of the eye based on the diffracted infrared light.

Disclosed is a method for generating a digital hologram representing a 3D scene including an object, an object being defined by points and their associated intensity. For each object, a prior step of calculating an “omnidirectional” angular spectrum of the light field emitted by an object in the scene on the surface of a geometric solid centered on the object, a surface of the solid being sampled according to a predetermined grid, a sample of the grid being associated with a vector frequency; for the scene, the following steps: —obtaining a pose of an observer in the world frame of reference; —deriving the hologram from the scene as a function of the pose obtained from the “multidirectional” angular spectra calculated for each object. The step of calculating an angular spectrum of the light field for each object of the scene takes into account predetermined viewing directions.

There is provided a holographic projector comprising a reflective liquid crystal display device. The reflective liquid crystal display device comprises a light-modulating layer between a first substrate and a second substrate substantially parallel to the first substrate. The light-modulating layer comprises planar-aligned nematic liquid crystals having positive dielectric anisotropy. The first substrate is substantially transparent and comprises a first alignment layer arranged to impart a first pre-tilt angle θ.sub..Math. on liquid crystals proximate the first substrate, wherein θ.sub.1>5°. The second substrate is substantially reflective and comprises a second alignment layer arranged to impart a second pre-tilt angle Θ.sub.2 on liquid crystals proximate the second substrate, wherein θ.sub.2>5°. The reflective liquid crystal display device further comprises a plurality of pixels defined on the light-modulating layer having a pixel repeat distance x, wherein x≤10 μm. The distance d between inside faces of the first substrate and second substrate satisfies 0.5 μm≤d≤3 μm, and the birefringence of the liquid crystal Δη≥0.20. The holographic projector further comprises a display driver arranged to drive the reflective liquid crystal display device to display a hologram by independently-driving each pixel at a respective modulation level selected from a plurality of modulation levels having a phase modulation value.

An optical system comprises an optically transmissive substrate comprising a metasurface which comprises a grating comprising a plurality of unit cells. Each unit cell comprises a laterally-elongated first nanobeam having a first width; and a laterally-elongated second nanobeam spaced apart from the first nanobeam by a gap, the second nanobeam having a second width larger than the first width. A pitch of the unit cells is 10 nm to 1 μm. The heights of the first and the second nanobeams are: 10 nm to 450 nm where a refractive index of the substrate is more than 3.3; and 10 nm to 1 μm where the refractive index is 3.3 or less.

In example embodiments, an optical system includes a waveguide having a first surface and a second surface substantially opposite the first surface. A reflective diffractive in-coupler is provided in the waveguide between the first and second surfaces for coupling blue light. A first transmissive diffractive in-coupler is provided in the waveguide between the reflective diffractive in-coupler and the second surface for coupling red light. Some embodiments further include a second transmissive diffractive in-coupler on the first surface for coupling blue light at high incident angles. Green light may be coupled by one or more of the in-couplers. The waveguide may further be provided with corresponding diffractive out-couplers for use in a waveguide display system.

New augmented reality display systems are provided, some of which incorporate “shifted-reality” techniques. In some embodiments, an augmented reality display system includes a matrix of light-augmenting pixels within a variable-transmission, semi-transparent screen (e.g., an augmented reality headset, comprising a semi-transparent screen) and creates redirected, attenuated and augmented light and shading to form and alter virtual objects. In some embodiments, a plurality of angle-alterable, shiftable sources (e.g., light-focusing and -directing pixels), aids in creating virtual objects of greater realism than conventional 3D imaging methods, and aids in reducing the appearance of other objects or conditions. In some aspects, existing images and objects may be shifted in perspective for an observer, and enhanced and overlaid with effects and demonstrative information related to them and a surrounding environment. In other aspects, the system builds and accesses an object structure and materials library and object inventory, enriching a user's augmented reality experience.

A three-dimensional (3D) holographic display system includes a projector that generates an image with a form of spatially varying modulation on a light beam; holographic processor that performs a holographic method on the image generated by the projector; and memory device that stores holographic data generated in a process of performing the holographic method by the holographic processor. An amplitude of a light field is adaptively replaced by the holographic processor according to significance of respective areas of the image.

A projector arranged to form a plurality of image reconstructions on different planes disposed on a common projection axis and a corresponding method is disclosed. A hologram engine is arranged to determine a hologram corresponding to each image for image reconstruction, and to form a diffractive pattern including the corresponding hologram for each image. A display engine is arranged to display each diffractive pattern and receive light such that an image reconstruction corresponding to each hologram is formed on a plane of the plurality of different planes. Each image reconstruction comprises image spots arranged in a pattern. Image spots of a first image reconstruction formed on a first plane are interposed between image spots of a second image reconstruction formed on a second plane.

The present disclosure relates to display systems and, more particularly, to augmented reality display systems. In one aspect, a method of fabricating an optical element includes providing a substrate having a first refractive index and transparent in the visible spectrum. The method additionally includes forming on the substrate periodically repeating polymer structures. The method further includes exposing the substrate to a metal precursor followed by an oxidizing precursor. Exposing the substrate is performed under a pressure and at a temperature such that an inorganic material comprising the metal of the metal precursor is incorporated into the periodically repeating polymer structures, thereby forming a pattern of periodically repeating optical structures configured to diffract visible light. The optical structures have a second refractive index greater than the first refractive index.

Several unique configurations for interferometric recording of volumetric phase diffractive elements with relatively high angle diffraction for use in waveguides are disclosed. Separate layer EPE and OPE structures produced by various methods may be integrated in side-by-side or overlaid constructs, and multiple such EPE and OPE structures may be combined or multiplexed to exhibit EPE/OPE functionality in a single, spatially-coincident layer. Multiplexed structures reduce the total number of layers of materials within a stack of eyepiece optics, each of which may be responsible for displaying a given focal depth range of a volumetric image. Volumetric phase type diffractive elements are used to offer properties including spectral bandwidth selectivity that may enable registered multi-color diffracted fields, angular multiplexing capability to facilitate tiling and field-of-view expansion without crosstalk, and all-optical, relatively simple prototyping compared to other diffractive element forms, enabling rapid design iteration.