Abstract: A device includes a pair of electrodes and a dynamic material disposed between the pair of electrodes, the dynamic material including a crystalline microstructure configured to change between at least two states in response to a change in an electric field between the two electrodes. A material includes tetragonal lead magnesium niobate-lead titanate (PMN-PT) and at least one lanthanide series element. A method includes doping a lead magnesium niobate-lead titanate material with at least one lanthanide series element, and processing the PMN-PT material to form tetragonal PMN-PT. A further method includes forming a low refractive index nanostructured grating over a carrier substrate, forming a high refractive index layer over the low refractive index grating to produce a nanostructured coupling element, forming an adhesive layer over the nanostructured coupling element, and affixing the nanostructured coupling element to a high index waveguide.

Abstract: Ultrasonic transducers may be used to track the position of an object. For example, eyewear such as a pair of glasses or other head-mounted device may use ultrasonic transducers to track a user's eye position and gaze direction. To increase positioning accuracy over short-range distances, an array of ultrasonic transducers with different center frequencies may be formed on a common substrate. The closely spaced ultrasonic transducers with relatively small individual bandwidths may be used to simulate a single transducer with a larger bandwidth. Control circuitry may adjust the phases of the transducers in the array to steer the ultrasonic signal beam towards the user's eye and/or to receive an ultrasonic signal beam from the direction of the user's eye. The control circuitry may use time delay and/or phase delay measurement techniques to determine a distance and/or direction to the user's eye using the ultrasonic transducer arrays.

Abstract: A spectrometer includes a transparent substrate including a first surface and a second surface that face each other and are substantially parallel to each other; a slit provided on the first surface and through which light is incident onto the transparent substrate; a spectrum optical system including metasurface including a plurality of nanostructures that are two-dimensionally arranged and satisfy a sub-wavelength scattering condition, wherein the metasurface includes a focusing metasurface which includes first nanostructures of the plurality of nanostructures, and is configured to reflect, disperse, and focus the light incident thereon through the slit, at different angles based on respective wavelengths; and a sensor configured to receive the light from the focusing metasurface. When L is a total length of an optical path from the slit to the sensor and D is a thickness of the transparent substrate, L and D satisfy the following inequality: L/D>3.

Abstract: Cascaded metasurfaces can control the phase, amplitude and polarization of an electromagnetic beam, shaping it in three dimensional configuration not achievable with other methods. Each cascaded metasurface has dielectric or metallic scatterers arranged in a period array. The shape of the scatterers determines the three dimensional configuration of the output beam and is determined with iterative calculations through computational simulations.

Abstract: Cascaded metasurfaces can control the phase, amplitude and polarization of an electromagnetic beam, shaping it in three dimensional configuration not achievable with other methods. Each cascaded metasurface has dielectric or metallic scatterers arranged in a period array. The shape of the scatterers determines the three dimensional configuration of the output beam and is determined with iterative calculations through computational simulations.

Abstract: Cascaded metasurfaces can control the phase, amplitude and polarization of an electromagnetic beam, shaping it in three dimensional configuration not achievable with other methods. Each cascaded metasurface has dielectric or metallic scatterers arranged in a period array. The shape of the scatterers determines the three dimensional configuration of the output beam and is determined with iterative calculations through computational simulations.

Abstract: Quantitative phase gradient microscopes (QPGM) using metasurface layers including birefringent lenses are disclosed. The birefringent lenses are manufactured by patterning nanoposts on two different transparent substrates or on opposite sides of the same transparent substrate. Methods to generate phase gradient images (PGI) of objects using the described devices are also disclosed.

Abstract: Metasurfaces for polarimetric imaging are disclosed. The described devices are built to split and focus light to various pixels on an image sensor for different polarization bases. This allows for complete characterization of polarization by measuring the four Stokes parameters over the area of each superpixel, which corresponds to the area of the pixels on the image sensor.

Abstract: A spectrometer includes a substrate; a slit which is provided on the substrate and through which light is incident onto the substrate; a metasurface including nanostructures that is configured to reflect and focus the light incident thereon through the slit, at different angles based on respective wavelengths; and a sensor which is provided on one side of the substrate that is opposite to another side of the substrate at which the metasurface is disposed, and configured to receive the light from the metasurface.

Abstract: A spectrometer includes a transparent substrate including a first surface and a second surface that face each other and are substantially parallel to each other; a slit provided on the first surface and through which light is incident onto the transparent substrate; a spectrum optical system including metasurface including a plurality of nanostructures that are two-dimensionally arranged and satisfy a sub-wavelength scattering condition, wherein the metasurface includes a focusing metasurface which includes first nanostructures of the plurality of nanostructures, and is configured to reflect, disperse, and focus the light incident thereon through the slit, at different angles based on respective wavelengths; and a sensor configured to receive the light from the focusing metasurface. When L is a total length of an optical path from the slit to the sensor and D is a thickness of the transparent substrate, L and D satisfy the following inequality: L/D>3.

Abstract: A pair of eyeglasses may include one or more adjustable lenses that are each configured to align with a respective one of a user's eyes. The adjustable lenses may include a foveated liquid crystal adjustable lens stacked with a non-liquid-crystal adjustable lens such as a fluid-filled lens or an Alvarez lens. The foveated adjustable lens may include electrically modulated optical material such as one or more liquid crystal cells. The liquid crystal cells may include arrays of electrodes that extend along one, two, three, four, or more than four directions. Control circuitry may apply control signals to the array of electrodes in each liquid crystal cell to produce a desired phase profile. Each lens may be foveated such that portions of the lens within the user's gaze exhibit a different phase profile than portions of the lens outside of the user's gaze.

Abstract: Hyperspectal imagers including reflective and transmissive metasurfaces are disclosed. The described metasurfaces are used collectively to disperse and focus light of different wavelengths and incident angles on a focal plane. The disclosed devices are compact and light, and can be used in systems and applications requiring stringent form factors.

Abstract: A spectrometer includes a substrate; a slit which is provided on the substrate and through which light is incident onto the substrate; a metasurface including nanostructures that is configured to reflect and focus the light incident thereon through the slit, at different angles based on respective wavelengths; and a sensor which is provided on one side of the substrate that is opposite to another side of the substrate at which the metasurface is disposed, and configured to receive the light from the metasurface.

Abstract: Compact optical devices such as spectrometers are realized with metasurfaces within a dielectric medium confined by reflective surfaces. The metasurfaces control the phase profiles of the reflected electromagnetic waves within the device. In a compact spectrometer, the metasurfaces within the device separate the electromagnetic waves in different wavelengths. The metasurfaces are designed according to their phase profile by varying the size of the array of scatterers.

Abstract: Quantitative phase gradient microscopes (QPGM) using metasurface layers including birefringent lenses are disclosed. The birefringent lenses are manufactured by patterning nanoposts on two different transparent substrates or on opposite sides of the same transparent substrate. Methods to generate phase gradient images (PGI) of objects using the described devices are also disclosed.

Abstract: Hyperspectal imagers including reflective and transmissive metasurfaces are disclosed. The described metasurfaces are used collectively to disperse and focus light of different wavelengths and incident angles on a focal plane. The disclosed devices are compact and light, and can be used in systems and applications requiring stringent form factors.

Abstract: A spectrometer includes a substrate; a slit which is provided on the substrate and through which light is incident onto the substrate; a metasurface including nanostructures that is configured to reflect and focus the light incident thereon through the slit, at different angles based on respective wavelengths; and a sensor which is provided on one side of the substrate that is opposite to another side of the substrate at which the metasurface is disposed, and configured to receive the light from the metasurface.

Abstract: A metasurface is defined by an array of scattering elements having a U shape, where the geometrical dimensions determining the U shape are determined according to the different phase profiles that the metasurface is meant to generate in response to an incident electromagnetic wave. The metasurface, therefore, generates different phase shifts as a function of the incident electromagnetic wave.

Abstract: Metasurfaces comprise an array of pillars in a lattice. The dimensions of the pillars and the spacing are varied to obtain desired optical properties. The dispersionless metasurfaces can focus optical light over a broad wavelength range. Specific dispersion profiles for the metasurfaces can be designed. Gratings can be fabricated having similar properties as the array of pillars. Pillars in the metasurfaces can have different cross-section profiles.

Abstract: A spectrometer includes a substrate; a slit which is provided on the substrate and through which light is incident onto the substrate; a metasurface including nanostructures that is configured to reflect and focus the light incident thereon through the slit, at different angles based on respective wavelengths; and a sensor which is provided on one side of the substrate that is opposite to another side of the substrate at which the metasurface is disposed, and configured to receive the light from the metasurface.