Abstract: According to various embodiments, a device may include a light-emitting diode (LED) to generate optical radiation at an operational wavelength with a divergent emission profile, such as a Lambertian emission profile, relative to a planar face thereof. A metalens may be positioned to modify the divergent emission profile of the optical radiation from the LED to have a modified transmission profile. The metalens may comprise, for example, a substrate and a two-dimensional array of passive pillars that extend from the substrate with a radially symmetric pattern of varying pillar diameters. The pillars may be spaced from one another according to a uniform subwavelength interelement spacing. The diameters of the pillars are selected as a function of the operational wavelength to provide a target phase gradient that modifies the divergent emission profile of the optical radiation from the LED to have the modified transmission profile.

Abstract: Systems and methods are described herein for manufacturing high-index, low-absorption materials for use in visible light optical metasurfaces. Methods of manufacturing or forming hydrogenated amorphous silicon (a-Si:H), silicon-rich nitride (SRN), and hydrogenated silicon-rich nitride (SRN:H) are described herein that exhibit high indices of refraction and low extinction coefficients for visible wavelengths of optical radiation. Optical metasurfaces, including optical metalenses and waveguide couplers, are described herein that utilize the a-Si:H, SRN, and/or SRN:H materials.

Abstract: Systems and methods are described herein for manufacturing high-index, low-absorption materials for use in visible light optical metasurfaces. Methods of manufacturing or forming hydrogenated amorphous silicon (a-Si:H), silicon-rich nitride (SRN), and hydrogenated silicon-rich nitride (SRN:H) are described herein that exhibit high indices of refraction and low extinction coefficients for visible wavelengths of optical radiation. Optical metasurfaces, including optical metalenses and waveguide couplers, are described herein that utilize the a-Si:H, SRN, and/or SRN:H materials.

Abstract: According to various embodiments, a device may include a light-emitting diode (LED) to generate optical radiation at an operational wavelength with a divergent emission profile, such as a Lambertian emission profile, relative to a planar face thereof. A metalens may be positioned to modify the divergent emission profile of the optical radiation from the LED to have a modified transmission profile. The metalens may comprise, for example, a substrate and a two-dimensional array of passive pillars that extend from the substrate with a radially symmetric pattern of varying pillar diameters. The pillars may be spaced from one another according to a uniform subwavelength interelement spacing. The diameters of the pillars are selected as a function of the operational wavelength to provide a target phase gradient that modifies the divergent emission profile of the optical radiation from the LED to have the modified transmission profile.

Abstract: A light-emitting diode includes a first semiconductor region of one of p- or n-conductivity types, a second semiconductor region of the other one of p- or n-conductivity types, forming a p-n junction with the first semiconductor region, and a quantum well layer at the p-n junction between the first and second semiconductor regions. A hyperbolic metamaterial structure is provided in the second semiconductor region. The hyperbolic metamaterial structure is coupled to the quantum well layer for extracting light from the quantum well layer. The hyperbolic metamaterial structure may be patterned to provide an array of nanoantennas to apodize the emitted beam, and to control the polarization state of the emitted beam.

Abstract: Various embodiments set forth liquid crystal (LC) patterning control systems in which LCs are aligned using locally applied magnetic fields. The index of refraction experienced by light propagating through an anisotropic LC is dependent on orientation. As a result, a phase difference may be imparted to an optical beam that is passed through, or reflected from, an array of LCs whose orientations are controlled via locally applied magnetic fields. In some embodiments, the locally applied magnetic fields may be generated by driving currents through wires that intersect at micro or nanomagnetic particles or at magnetic domains, or by applying voltages to micro or nanocoils wrapped around high-permeability cores, among other things.

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: Examples include a device including a nanovoided polymer element having a first surface and a second surface, a first plurality of electrodes disposed on the first surface, a second plurality of electrodes disposed on the second surface, and a control circuit configured to apply an electrical potential between one or more of the first plurality of electrodes and one or more of the second plurality of electrodes to induce a physical deformation of the nanovoided polymer element.

Abstract: Antennas such as flat panel, leaky wave antennas with directional coupler feeds and waveguides are disclosed. In one example, an antenna includes a surface having antenna elements, a guided wave transmission line, and a coupling surface. The guided wave transmission line provides a guided feed wave. The coupling surface is between and separates the guided wave transmission line and the surface having antenna elements. The coupling surface controls coupling of the guided feed wave to the antenna elements. The coupling surface can also spatially filter the guided feed wave to provide a more uniform power density for the antenna elements. The guided feed wave can be a high power density electromagnetic wave or a density radially decaying electromagnetic wave.

Abstract: An apparatus may include (1) a planar liquid-crystal structure including a plurality of liquid crystals, and (2) a plurality of electrodes coupled to the planar liquid-crystal structure such that (a) when a first plurality of voltages are applied to at least some of the plurality of electrodes, the plurality of liquid crystals are oriented such that the planar liquid-crystal structure operates as a diffraction grating having a first pitch, and (2) when a second plurality of voltages are applied to at least some of the plurality of electrodes, the plurality of liquid crystals are oriented such that the planar liquid-crystal structure operates as a diffraction grating having a second pitch different from the first pitch.

Abstract: A light-emitting diode includes a first semiconductor region of one of p- or n-conductivity types, a second semiconductor region of the other one of p- or n-conductivity types, forming a p-n junction with the first semiconductor region, and a quantum well layer at the p-n junction between the first and second semiconductor regions. A hyperbolic metamaterial structure is provided in the second semiconductor region. The hyperbolic metamaterial structure is coupled to the quantum well layer for extracting light from the quantum well layer. The hyperbolic metamaterial structure may be patterned to provide an array of nanoantennas to apodize the emitted beam, and to control the polarization state of the emitted beam.

Abstract: Various embodiments set forth liquid crystal (LC) patterning control systems in which LCs are aligned using locally applied magnetic fields. The index of refraction experienced by light propagating through an anisotropic LC is dependent on orientation. As a result, a phase difference may be imparted to an optical beam that is passed through, or reflected from, an array of LCs whose orientations are controlled via locally applied magnetic fields. In some embodiments, the locally applied magnetic fields may be generated by driving currents through wires that intersect at micro or nanomagnetic particles or at magnetic domains, or by applying voltages to micro or nanocoils wrapped around high-permeability cores, among other things.

Abstract: A method and apparatus for improved switching speed and/or tunability for radio-frequency (RF) devices are described. In one embodiment, a liquid crystal (LC) component comprises an LC structure in a mixture with right-handed (R) and left-handed (S) chiral dopants.

Abstract: Various embodiments set forth liquid crystal (LC) patterning control systems in which LCs are aligned using locally applied magnetic fields. The index of refraction experienced by light propagating through an anisotropic LC is dependent on orientation. As a result, a phase difference may be imparted to an optical beam that is passed through, or reflected from, an array of LCs whose orientations are controlled via locally applied magnetic fields. In some embodiments, the locally applied magnetic fields may be generated by driving currents through wires that intersect at micro or nanomagnetic particles or at magnetic domains, or by applying voltages to micro or nanocoils wrapped around high-permeability cores, among other things.

Abstract: A manufacturing system for fabricating self-aligned grating elements with a variable refractive index includes a patterning system, a deposition system, and an etching system. The manufacturing system performs a lithographic patterning of one or more photoresists to create a stack over a substrate. The manufacturing system performs a conformal deposition of a protective coating on the stack. The manufacturing system performs a deposition of a first photoresist of a first refractive index on the protective coating. The manufacturing system performs a removal of the first photoresist to achieve a threshold value of first thickness. The manufacturing system performs a deposition of a second photoresist of a second refractive index on the first photoresist. The second refractive index is greater than the first refractive index. The manufacturing system performs a removal of the second photoresist to achieve a threshold value of second thickness to form a portion of an optical grating.

Abstract: A form birefringent optical element includes a structured layer and a dielectric environment disposed over the structured layer. At least one of the structured layer and the dielectric environment includes a nanovoided polymer, the nanovoided polymer having a first refractive index in an unactuated state and a second refractive index different than the first refractive index in an actuated state. Actuation of the nanovoided polymer can be used to reversibly control the form birefringence of the optical element. Various other apparatuses, systems, materials, and methods are also disclosed.

Abstract: A multilayer grating is a diffraction grating that includes a plurality of layers. The plurality of layers arranged to form a 2-dimensional grating, the layers including at least a first patterned layer and a second patterned layer. The first patterned layer includes a plurality of different materials that are arranged in a first pattern such that the first patterned layer has a first index profile. The second patterned layer includes a plurality of different materials that are arranged in a second pattern such that the second patterned layer has a second index profile that is inverted relative to the first index profile. Ambient light incident on the first patterned layer and the second patterned layer creates a first diffracted ray and a second diffracted ray, respectively, and the first diffracted ray and the second diffracted ray destructively interfere with each other based in part on the inverted index profile.

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: An optical element includes a nanovoided polymer layer having a first refractive index in an unactuated state and a second refractive index different than the first refractive index in an actuated state. Compression or expansion of the nanovoided polymer layer, for instance, can be used to reversibly control the size and shape of the nanovoids within the polymer layer and hence tune its refractive index over a range of values, e.g., during operation of the optical element. Various other apparatuses, systems, materials, and methods are also disclosed.

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.