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: 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: Metasurfaces comprise an array of meta-atoms in a stretchable polymer. The dimensions and shapes of the meta-atoms and the spacing are varied to obtain desired optical properties. Any optical wavefront, for different wavelengths, illumination angles, and polarization states can be designed with proper design of the meta-atoms. As the metasurface is stretched, the distance between the meta-atoms changes, modifying the optical response, while the dimensions of the meta-atoms remains constant.

Abstract: An image sensor includes a substrate, thin lenses disposed on a first surface of the substrate and configured to concentrate lights incident on the first surface, and light-sensing cells disposed on a second surface of the substrate, the second surface facing the first surface, and the light-sensing cells being configured to sense lights passing through the thin lenses, and generate electrical signals based on the sensed lights. A first thin lens and second thin lens of the thin lenses are configured to concentrate a first light and a second light, respectively, of the incident lights onto the light-sensing cells, the first light having a different wavelength than the second light.

Abstract: A neural probe for light stimulation of a tissue is provided. The probe includes a base that has light supplying circuitry, and one or more elongated microsized shanks extending from the base. Each shank has a longitudinal axis and includes one or more waveguides extending along the shank's length, with the waveguides being optically connected to the light supplying circuitry. In addition, each of the waveguides is optically connected to a diffraction grating coupler that emits a light beam from the shank when light passes from the base through the waveguide and to the diffraction grating coupler. The emitted light beam has a propagation direction at a set angle relative to an axis that is substantially normal to the longitudinal axis of the shank. A method for stimulating a tissue using the neural probe is also provided.

Abstract: An image sensor includes an optical sensor layer including a plurality of light-sensitive cells configured to sense light to generate electrical signals, and a color filter array layer disposed on the optical sensor layer and including a plurality of color filters respectively facing the plurality of light-sensitive cells. Each of the plurality of color filters includes a nanostructure in which a first material having a first refractive index and a second material having a second refractive index higher than the first refractive index are arranged. The first material and the second material are alternatively positioned at an interval less than a central wavelength of a color of the color filter. Thus, a thin image sensor having good wavelength selectivity and suitable for obtaining high resolution images is provided.

Abstract: A method of manufacturing an image sensor includes: preparing a sensor substrate including: a sensor layer including a photosensitive cell; and a signal line layer including lines to receive electric signals from the photosensitive cell; forming a first material layer having a first refractive index on the sensor substrate; and forming a nanopattern layer on the first material layer, the nanopattern layer including a material having a second refractive index different from the first refractive index.

Abstract: A spatial filtering apparatus includes a composite filter including first filter patterns respectively having a first phase profile, and second filter patterns respectively having a second phase profile, wherein the first filter patterns and the second filter patterns overlap with each other, wherein first light in a first polarization direction that is emitted on the composite filter is first spatially filtered by the first filter patterns, and wherein second light in a second polarization direction that is emitted on the composite filter is second spatially filtered by the second filter patterns.

Abstract: An image sensor includes a substrate, thin lenses disposed on a first surface of the substrate and configured to concentrate lights incident on the first surface, and light-sensing cells disposed on a second surface of the substrate, the second surface facing the first surface, and the light-sensing cells being configured to sense lights passing through the thin lenses, and generate electrical signals based on the sensed lights. A first thin lens and second thin lens of the thin lenses are configured to concentrate a first light and a second light, respectively, of the incident lights onto the light-sensing cells, the first light having a different wavelength than the second light.

Abstract: An image sensor includes an optical sensor layer including a plurality of light-sensitive cells configured to sense light to generate electrical signals, and a color filter array layer disposed on the optical sensor layer and including a plurality of color filters respectively facing the plurality of light-sensitive cells. Each of the plurality of color filters includes a nanostructure in which a first material having a first refractive index and a second material having a second refractive index higher than the first refractive index are arranged. The first material and the second material are alternatively positioned at an interval less than a central wavelength of a color of the color filter. Thus, a thin image sensor having good wavelength selectivity and suitable for obtaining high resolution images is provided.

Abstract: An image sensor includes a substrate, a first thin lens configured to concentrate light of a first wavelength, and including a plurality of first scatterers disposed on the substrate. The plurality of first scatterers includes a material having a refractive index greater than a refractive index of the substrate. The image sensor further includes a plurality of light-sensing cells configured to sense the light concentrated by the first thin lens.

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: 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: Structures for scattering light at multiple wavelengths are disclosed. Scattering elements are fabricated with different geometric dimensions and arrangements, to scatter or focus light at the same focal distance for each wavelength, or at different focal distances according to the desired application. The scattering elements fabricated on a substrate can be peeled off with a polymer matrix and attached to a lens to modify the optical properties of the lens.

Abstract: Structures for scattering light at multiple wavelengths are disclosed. Scattering elements are fabricated with different geometric dimensions and arrangements, to scatter or focus light at the same focal distance for each wavelength, or at different focal distances according to the desired application. Scattering elements can be circular or elliptical posts, allowing polarization dependent scattering. The elements can have different orientations to scatter light from multiple wavelengths at the desired focal length.

Abstract: A birefringent metasurface lens formed by an array of nanoposts generates different phase profiles for different incident electromagnetic waves of different polarization. A first polarization is focused at a first focal length, while a second polarization is focused at a second focal length. A variable phase retarder and a polarizer generate interference patterns for each phase difference between the two incident polarizations. The interference patterns are used to generate a hologram, allowing reconstruction of the image of an object.

Abstract: Complex wavefront engineering is realized through a random metasurface phase mask backed by a phase-only spatial light modulator. The metasurface consists of an array of subwavelength nanoscatterers which give the metasurface a pre-arranged disorder. Since the transmission matrix of the disordered metasurface is known, there is no need for extensive characterization measurements which are instead required in standard disordered optical devices.

Abstract: A polarimeter for measuring a polarization rotation caused by a measurement object is provided, the polarimeter including an optically active material. The polarimeter includes a light source unit for irradiating a measurement object with light having a specific polarization; an anisotropic meta surface element for splitting reaction light, obtained by reacting the light of the specific polarization irradiated by the light source unit with the measurement object, into first and second reaction light; and a detection unit for detecting the first and second reaction light separated by the anisotropic meta surface element according to polarization. The polarization rotation caused by the measurement object may be calculated by comparing detection signals of the first and second reaction light detected by the detection unit.

Abstract: A focusing device includes a substrate and a plurality of scatterers provided at both sides of the substrate. The scatterers on the both sides of the focusing device may correct geometric aberration, and thus, a field of view (FOV) of the focusing device may be widened.

Abstract: An optical device has a first metasurface. A high-contrast pattern of the first metasurface is operable for modifying, over a first phase profile, a phase front of an incident light beam. A second metasurface, is disposed over a plane parallel to the first metasurface with a second high-contrast pattern and operable for shaping, over a second phase profile, the modified phase front of the incident light beam into a converging spherical phase front. A spacer layer, in which the modified phase front of the incident light beam diffracts, is disposed in a controllably changeable separation between the first and second metasurfaces. Controllably changing the separation between the first and the second metasurfaces by a first distance correspondingly changes the position of the focus point of the converging spherical phase front by a second distance.