A multilayer waveguide coupler comprising a first grating and a second grating is provided. Each first copropagating waveguide of the first grating has a first periodically modulated width. Each second copropagating waveguide of the second grating has a second periodically modulated width. The second grating is positioned so that a phase offset is present between the first periodically modulated width of the first copropagating waveguides and the second periodically modulated width of the second copropagating waveguides. The grating spaced distance and phase offset are selected so that light diffracted out of the first copropagating waveguides and the second copropagating waveguides in the first direction interferes constructively to form the first light beam and light diffracted out of the first copropagating waveguides and the second copropagating waveguides in the second direction interferes destructively.

A meta projector includes an edge emitting device configured to emit light through a side surface thereof, a meta-structure layer spaced apart from the upper surface of the edge emitting device that includes a plurality of nanostructures having a sub-wavelength shape dimension smaller than a wavelength of the light emitted from the edge emitting device, and a path changing member configured to change a path of the light emitted from the edge emitting device so as to direct the path toward the meta-structure layer. The meta projector may thus be configured to emit a light pattern of structured light, based on directing the light emitted from the edge emitting device through the meta-structure layer, while having a relatively compact device size.

A plasma etching method using a Faraday cage, including: providing an etch substrate in a Faraday cage, where the etch substrate includes a metal mask provided on one surface thereof, and where an upper surface of the Faraday cage is provided with a mesh portion; a first patterning step of forming a first pattern area on the etch substrate; and a second patterning step of forming a second pattern area on the etch substrate after shielding at least a part of the mesh portion with a shutter. The first pattern area includes a first groove pattern having a depth gradient of 0 to 40 nm per 5 mm, and the second pattern area includes a second groove pattern having a depth gradient of 50 to 300 nm per 5 mm.

An optical element includes a substrate, an intermediate layer, a topmost layer, and a contiguous multitude of recessed and non-recessed areal regions. The intermediate layer is formed over a top surface of the substrate and has a refractive index n.sub.I. The topmost layer is formed directly on the intermediate layer and has a refractive index n.sub.T where n.sub.T≠n.sub.I. The intermediate and topmost layers are substantially transparent over an operational wavelength range that includes a design wavelength λ.sub.0. A subset of areal regions has a largest transverse dimension less than about λ.sub.0. Each non-recessed areal region includes corresponding portions of the intermediate and topmost layers. Each recessed areal region extends entirely through the topmost layer and at least partly through the intermediate layer. A fill medium fills the recessed areal regions. The areal regions are variously sized and distributed transversely across the optical element.

A light field imaging device may include a diffraction grating assembly configured to receive an optical wavefront from a scene and including one or more diffraction gratings. Each diffraction grating has a refractive index modulation pattern with a grating period along a grating axis and is configured to generate a diffracted wavefront. The device may also include a pixel array configured to detect the diffracted wavefront in a near-field region. The pixel array includes light-sensitive pixels and a pixel pitch along the grating axis that is equal to or larger than the grating period. Each pixel samples a portion of the diffracted wavefront and generates a pixel response. The pixels include groups or pairs of adjacent pixels, where the adjacent pixels in each group or pair have different pixel responses as a function of the angle of incidence of the optical wavefront. Light field imaging methods are also disclosed.

A diffractive optical element having, on a surface of a transparent substrate, a plurality of types of regions which provide different phase modulation to an incident light, wherein each of the regions has a microstructure formed with concave and convex portions of which sizes are smaller than the wavelength of the incident light, and wherein in the microstructure, a ratio of the width of the convex portion and the width of the concave portion in the concave and convex portions and the depth of the concave portion are different for each type of region.

A multilayer waveguide coupler comprising a first grating and a second grating is provided. Each first copropagating waveguide of the first grating has a first periodically modulated width. Each second copropagating waveguide of the second grating has a second periodically modulated width. The second grating is positioned so that a phase offset is present between the first periodically modulated width of the first copropagating waveguides and the second periodically modulated width of the second copropagating waveguides. The grating spaced distance and phase offset are selected so that light diffracted out of the first copropagating waveguides and the second copropagating waveguides in the first direction interferes constructively to form the first light beam and light diffracted out of the first copropagating waveguides and the second copropagating waveguides in the second direction interferes destructively.

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.

Various embodiments set forth a foveated display system and components thereof. The foveated display system includes a peripheral display module disposed in series with a foveal display module. The peripheral display module is configured to generate low-resolution, large field of view imagery for a user's peripheral vision. The foveal display module is configured to perform foveated rendering in which high-resolution imagery is focused towards a foveal region of the user's eye gaze. The peripheral display module may include a diffuser that is disposed within a pancake lens, which is a relatively compact design. The foveal display module may include a Pancharatnam-Berry Phase grating stack that increases the steering range of a beam-steering device such that a virtual image can be steered to cover an entire field of view visible to the user's eye.

An exemplary imaging device includes an optical sensor having an optical axis, a lens positioned to focus light from a scene onto the optical sensor, a matrix of variable-phase optical elements that are dimensioned to introduce at least two different phase delays into a wavefront of a light signal received from the scene through the lens, a housing that secures the matrix of variable-phase optical elements between the optical sensor and the lens, and a processing subsystem programmed to determine a phase difference associated with the light signal based on the at least two different phase delays. Related systems and methods are also provided.