Abstract: A method of manufacturing a waveguide having a combination of a binary grating structure and a blazed grating structure includes cutting a substrate off-axis, depositing a first layer on the substrate, and depositing a resist layer on the first layer. The resist layer includes a pattern. The method also includes etching the first layer in the pattern using the resist layer as a mask. The pattern includes a first region and a second region. The method further includes creating the binary grating structure in the substrate in the second region and creating the blazed grating structure in the substrate in the first region.

Abstract: 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 ?m. 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 ?m where the refractive index is 3.3 or less.

Abstract: A method of fabricating non-uniform gratings includes implanting different densities of ions into corresponding areas of a substrate, patterning, e.g., by lithography, a resist layer on the substrate, etching the substrate with the patterned resist layer, and then removing the resist layer from the substrate, leaving the substrate with at least one grating having non-uniform characteristics associated with the different densities of ions implanted in the areas. The method can further include using the substrate having the grating as a mold to fabricate a corresponding grating having corresponding non-uniform characteristics, e.g., by nanoimprint lithography.

Abstract: A method of manufacturing a waveguide having a combination of a binary grating structure and a blazed grating structure includes cutting a substrate off-axis, depositing a first layer on the substrate, and depositing a resist layer on the first layer. The resist layer includes a pattern. The method also includes etching the first layer in the pattern using the resist layer as a mask. The pattern includes a first region and a second region. The method further includes creating the binary grating structure in the substrate in the second region and creating the blazed grating structure in the substrate in the first region.

Abstract: Metasurfaces provide compact optical elements in head-mounted display systems to, e.g., incouple light into or outcouple light out of a waveguide. The metasurfaces may be formed by a plurality of repeating unit cells, each unit cell comprising two sets or more of nanobeams elongated in crossing directions: one or more first nanobeams elongated in a first direction and a plurality of second nanobeams elongated in a second direction. As seen in a top-down view, the first direction may be along a y-axis, and the second direction may be along an x-axis. The unit cells may have a periodicity in the range of 10 nm to 1 ?m, including 10 nm to 500 nm or 300 nm to 500 nm. Advantageously, the metasurfaces provide diffraction of light with high diffraction angles and high diffraction efficiencies over a broad range of incident angles and for incident light with circular polarization.

Abstract: A device includes an input coupling grating having a first grating structure characterized by a first set of grating parameters. The input coupling grating is configured to receive light from a light source. The device also includes an expansion grating having a second grating structure characterized by a second set of grating parameters varying in at least two dimensions. The second grating structure is configured to receive light from the input coupling grating. The device further includes an output coupling grating having a third grating structure characterized by a third set of grating parameters. The output coupling grating is configured to receive light from the expansion grating and to output light to a viewer.

Abstract: Plasma etching processes for forming patterns in high refractive index glass substrates, such as for use as waveguides, are provided herein. The substrates may be formed of glass having a refractive index of greater than or equal to about 1.65 and having less than about 50 wt % SiO2. The plasma etching processes may include both chemical and physical etching components. In some embodiments, the plasma etching processes can include forming a patterned mask layer on at least a portion of the high refractive index glass substrate and exposing the mask layer and high refractive index glass substrate to a plasma to remove high refractive index glass from the exposed portions of the substrate. Any remaining mask layer is subsequently removed from the high refractive index glass substrate. The removal of the glass forms a desired patterned structure, such as a diffractive grating, in the high refractive index glass substrate.

Abstract: A method of fabricating non-uniform gratings includes implanting different densities of ions into corresponding areas of a substrate, patterning, e.g., by lithography, a resist layer on the substrate, etching the substrate with the patterned resist layer, and then removing the resist layer from the substrate, leaving the substrate with at least one grating having non-uniform characteristics associated with the different densities of ions implanted in the areas. The method can further include using the substrate having the grating as a mold to fabricate a corresponding grating having corresponding non-uniform characteristics, e.g., by nanoimprint lithography.

Abstract: 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.

Abstract: In some embodiments, a display device includes one or more waveguides having a vapor deposited light absorbing film on edges of the waveguide to mitigate ghost images. In some embodiments, the film is formed directly on the edge of the waveguide by a vapor deposition, such as an evaporative deposition process. In some embodiments, the light absorbing films may comprise carbon, for example carbon in the form of one or more allotropes of carbon, such as fullerenes, or black silicon.

Abstract: Metasurfaces provide compact optical elements in head-mounted display systems to, e.g., incouple light into or outcouple light out of a waveguide. The metasurfaces may be formed by a plurality of repeating unit cells, each unit cell comprising two sets or more of nanobeams elongated in crossing directions: one or more first nanobeams elongated in a first direction and a plurality of second nanobeams elongated in a second direction. As seen in a top-down view, the first direction may be along a y-axis, and the second direction may be along an x-axis. The unit cells may have a periodicity in the range of 10 nm to 1 ?m, including 10 nm to 500 nm or 300 nm to 500 nm. Advantageously, the metasurfaces provide diffraction of light with high diffraction angles and high diffraction efficiencies over a broad range of incident angles and for incident light with circular polarization.

Abstract: Antireflection coatings for metasurfaces are described herein. In some embodiments, the metasurface may include a substrate, a plurality of nanostructures thereon, and an antireflection coating disposed over the nanostructures. The antireflection coating may be a transparent polymer, for example a photoresist layer, and may have a refractive index lower than the refractive index of the nanostructures and higher than the refractive index of the overlying medium (e.g., air). Advantageously, the antireflection coatings may reduce or eliminate ghost images in an augmented reality display in which the metasurface is incorporated.

Abstract: Plasma etching processes for forming patterns in high refractive index glass substrates, such as for use as waveguides, are provided herein. The substrates may be formed of glass having a refractive index of greater than or equal to about 1.65 and having less than about 50 wt % SiO2. The plasma etching processes may include both chemical and physical etching components. In some embodiments, the plasma etching processes can include forming a patterned mask layer on at least a portion of the high refractive index glass substrate and exposing the mask layer and high refractive index glass substrate to a plasma to remove high refractive index glass from the exposed portions of the substrate. Any remaining mask layer is subsequently removed from the high refractive index glass substrate. The removal of the glass forms a desired patterned structure, such as a diffractive grating, in the high refractive index glass substrate.

Abstract: An optical device includes a liquid crystal layer having a first plurality of liquid crystal molecules arranged in a first pattern and a second plurality of liquid crystal molecules arranged in a second pattern. The first and the second pattern are separated from each other by a distance of about 20 nm and about 100 nm along a longitudinal or a transverse axis of the liquid crystal layer. The first and the second plurality of liquid crystal molecules are configured as first and second grating structures that can redirect light of visible or infrared wavelengths.

Abstract: A method of fabricating non-uniform gratings includes implanting different densities of ions into corresponding areas of a substrate, patterning, e.g., by lithography, a resist layer on the substrate, etching the substrate with the patterned resist layer, and then removing the resist layer from the substrate, leaving the substrate with at least one grating having non-uniform characteristics associated with the different densities of ions implanted in the areas. The method can further include using the substrate having the grating as a mold to fabricate a corresponding grating having corresponding non-uniform characteristics, e.g., by nanoimprint lithography.

Abstract: A method of manufacturing a waveguide having a combination of a binary grating structure and a blazed grating structure includes cutting a substrate off-axis, depositing a first layer on the substrate, and depositing a resist layer on the first layer. The resist layer includes a pattern. The method also includes etching the first layer in the pattern using the resist layer as a mask. The pattern includes a first region and a second region. The method further includes creating the binary grating structure in the substrate in the second region and creating the blazed grating structure in the substrate in the first region.

Abstract: A device includes an input coupling grating having a first grating structure characterized by a first set of grating parameters. The input coupling grating is configured to receive light from a light source. The device also includes an expansion grating having a second grating structure characterized by a second set of grating parameters varying in at least two dimensions. The second grating structure is configured to receive light from the input coupling grating. The device further includes an output coupling grating having a third grating structure characterized by a third set of grating parameters. The output coupling grating is configured to receive light from the expansion grating and to output light to a viewer.

Abstract: 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 ?m. 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 ?m where the refractive index is 3.3 or less.

Abstract: A display system comprises a waveguide having light incoupling or light outcoupling optical elements formed of a metasurface. The metasurface is a multilevel (e.g., bi-level) structure having a first level defined by spaced apart protrusions formed of a first optically transmissive material and a second optically transmissive material between the protrusions. The metasurface also includes a second level formed by the second optically transmissive material. The protrusions on the first level may be patterned by nanoimprinting the first optically transmissive material, and the second optically transmissive material may be deposited over and between the patterned protrusions. The widths of the protrusions and the spacing between the protrusions may be selected to diffract light, and a pitch of the protrusions may be 10-600 nm.

Abstract: This disclosure provides systems, methods, and apparatus related to probes for multidimensional nanospectroscopic imaging. In one aspect, a method includes providing a transparent tip comprising a dielectric material. A four-sided pyramidal-shaped structure is formed at an apex of the transparent tip using a focused ion beam. Metal layers are deposited over two opposing sides of the four-sided pyramidal-shaped structure.