Abstract: Wide-angle optical functionality is beneficial for imaging and image projection devices. Conventionally, wide-angle operation is attained by a complicated assembly of optical elements. Recent advances have led to meta-surface lenses or meta-lenses, which are ultra-thin planar lenses with nanoantennas that control the phase, amplitude, and/or polarization of light. Here, we present a meta-lens capable of diffraction-limited focusing and imaging over an unprecedented >170° angular field of view (FOV). The lens is integrated on a one-piece flat substrate and includes an aperture on one side and a single meta-surface on the other side. The meta-surface corrects third-order Seidel aberrations, including coma, astigmatism, and field curvature. The meta-lens has a planar focal plane, which enables considerably simplified system architectures for imaging and projection.

Abstract: Reversible phase-change materials (PCMs) can be added to or incorporated into meta-lenses, wave plates, waveguides, gratings, and other optical components to form active optical devices with controllable and adjustable optical characteristics. Local heating can be used to induce solid-state phase changes and large refractive index changes in the PCMs. The phase and index changes can provide large changes in the device's optical characteristics. Optical devices with PCM can be used for imaging applications, orbital angular momentum control, photonic integrated circuits and optical communication systems, beam steering, and other application.

Abstract: Meta-optic systems are described that include multi-function metasurfaces formed from a plurality of meta-atoms. A multi-function metasurface can exhibit two or more different optical functions for two or more different states of light incident on the metasurface. Different states of light include different polarizations, different wavelengths, and different angles of incidence. Different optical functions include distance sensing, converging, diverging, image formation, and patterned light formation. The multi-function metasurface can selectively impart different phase profiles to an incident beam depending on the incident beam's state of light.

Abstract: An optical pattern projection device includes a light emitter or light emitter array and one or more flat optics layers configured to project and split light beams from the light emitters to generate a projected light pattern including multiple sub-patterns each corresponding to one of the light emitters. The flat optics layers may include a single optical metasurface containing superposed beam shaping and/or projection phase profile and a beam splitting phase profile. Alternatively, the flat optics layers may include two optical metasurfaces each containing a light shaping and/or projection phase profile, which together produce a linear relationship between light emitter position and corresponding beam projection angle, and one or both of the metasurfaces further contains a superposed beam splitting phase profile. The light shaping and/or projection phase profile may have a function similar to a micro-lens array. A structured light camera combining optical pattern projection and detection is also provided.

Abstract: System for free-space light coupling between 2-dimensional light transmitter and receiver arrays using flat optics. The system includes: a transmitter array configured to emit one or more light beams; a first flat optic configured to receive the light beams from the transmitter array and generate one or more intermediate light beams; a first spacer disposed between the light transmitter array and the first flat optic; a receiver array; a second flat optic configured to receive the intermediate light beams and generate one or more output light beams toward the receiver array; and a second spacer disposed between the second flat optic and the light receiver array. The TX and RX portions of the light coupling system may be used in LiDAR systems as the light emitter (beam steerer) and detector, respectively. The flat optics are configured to provide a wide field of view for the LiDAR.

Abstract: Meta-lens based ocular imaging, near-eye display, and eye-tracking systems are described. The systems can include a single focusing optic and an integrated circuit that provides illumination light and includes an imaging array. The focusing optic includes meta-atoms formed on a substrate. The systems may have no moving parts and achieve imaging or image-projection fields-of-view approaching or exceeding 180 degrees. Because of their low part count, the systems can be robust and have a very small form factor.

Abstract: A wide field-of-view sensor or projector includes a transparent substrate with one or more apertures on one side, and one or more chip stacks joined to the opposite side. Each chip stack includes a flat optics layer (e.g., metasurface), at least one spacer layer, an optional filter layer, and either an image sensor or a light source. In one example, two apertures and two corresponding chip stacks are provided; both chip stacks include image sensors but different metasurfaces and filters to capture different information from the scene. In an alternative embodiment, the two chip stacks include a light source and an image sensor, to function as a light projector and a light receiver, respectively. In other examples, two apertures and a single chip stack are provided, where the single chip stack include two metasurface and/or two filters corresponding to the two apertures.

Abstract: We disclose an on-chip photonic spectroscopy system capable of dramatically improving the signal-to-noise ratio (SNR), dynamic range, and reconstruction quality of Fourier transform spectrometers. Secondly, we disclose a system of components that makes up a complete on-chip RF spectrum analyzer with low-cost and high-performance.

Abstract: A method of performing Raman spectroscopy can include guiding a Raman pump beam with an optical fiber, where the Raman pump beam inducing fluorescence in the optical fiber. The beam and the fluorescence are coupled to a photonic integrated circuit (PIC) via the fiber. The beam is used to excite a sample in optical communication with the PIC via evanescent coupling and induces Raman scattering in the sample. The Raman scattering is collected via the PIC, and the Raman pump beam as well as the fluorescence is filtered out from the Raman scattering via the PIC.

Abstract: Meta-lens based ocular imaging, near-eye display, and eye-tracking systems are described. The systems can include a single focusing optic and an integrated circuit that provides illumination light and includes an imaging array. The focusing optic includes meta-atoms formed on a substrate. The systems may have no moving parts and achieve imaging or image-projection fields-of-view approaching or exceeding 180 degrees. Because of their low part count, the systems can be robust and have a very small form factor.

Abstract: The present technology is related to optics and optical systems, particularly to photonic packaging, optical coupling, optical interconnects, micro-optics, and their fabrication. The present technology includes free-form micro-optical coupler architectures and systems with superb optical performance and a high-throughput method of fabricating large-area coupler arrays for scalable manufacturing. Embodiments include chip-to-fiber-array, chip-to-chip, chip-to-interposer, and chip-to-free-space couplers for applications including photonic packaging, optical communications, LiDAR, optical trapping and manipulation, augmented reality, virtual reality, and sensing.

Abstract: A sensor, such as a photoplethysmography sensor, for non-invasively monitoring a characteristic of an organism, such as a vital body sign. The sensor has multiple light sources disposed on a substrate and an array of optical probing channels for conveying light from the light sources to a probed region. Each detector pixel of an array of detector pixels receives light from a respective optical detection channel after interaction with a subregion of the probed region and spatial filtering, and generates a corresponding pixel signal.

Abstract: An optical device as described herein includes a host substrate fabricated from a dielectric material transparent in the Infrared range. Additionally, the optical device as discussed herein includes multiple elements disposed on the host substrate. The multiple elements are spaced apart from each other on the host substrate in accordance with a desired pattern. Each of the multiple elements disposed in the host substrate is fabricated from a second material having a refractive index of greater than 4.5. Such an optical device provides an improvement over conventional optical devices that operate in the Infrared range.

Abstract: An optical coherence tomography (OCT) engine includes a digital Fourier-Transform (dFT) spectrometer, a tunable delay line, and a high-speed optical phased array (OPA) scanner integrated onto a single chip. The broadband dFT spectrometer offers superior signal-to-noise ratio (SNR) and fine axial resolution; the tunable delay line ensures large imaging depth by circumventing sensitivity roll-off; and the OPA can scan the beams at GHz rates without moving parts. Unlike conventional spectrometers, the dFT spectrometer employs an optical switch network to retrieve spectral information in an exponentially scaling fashion—its performance doubles with every new optical switch added to the network. Moreover, it also benefits from the Fellgett's advantage, which provide a significant SNR edge over conventional spectrometers. The tunable delay line balances the path length difference between the reference and sample arms, avoiding any need to sample high-frequency spectral fringes.

Abstract: The present technology is related to optics, optical systems, and optically induced micro-/nano-fabrication methods. It includes metasurface optics, direct laser writing, and microscopy. Flat optic devices, architectures, and methods can achieve superb optical performance and structural simplicity compared to traditional bulk optical systems.

Abstract: Reflecting light beams off of microscale three-dimensional (3D) freeform surfaces can yield highly efficient coupling into and out of optical waveguides, optical fibers, and photonic chips. The structure of the 3D freeform reflective surface determines the shape of the reflected beam. This allows freeform reflectors to control the mode profile, rotation angle, and divergence angle of light beams. Control of beam shape enables mode matching between source output mode and target input mode, which results in low-loss optical coupling. An inventive freeform reflective surface can direct light beams in plane or out of plane via specular reflection or total internal reflection. A photonic integrated circuit with this type of freeform optical coupler can operate with a bandwidth range of at least 400 nm, potentially encompassing all visible or telecommunications wavelengths, and can be volume manufactured in photonic chips.

Abstract: Alloys of GeSbSeTe (GSST) can be used to make actively tunable infrared transmission filters that are small, fast, and solid-state. These filters can be used for hyperspectral imaging, 3D LIDAR, portable bio/chem sensing systems, thermal emission control, and tunable filters. GSST is a low-loss phase-change material that can switch from a low-index (n=3), amorphous state to a high-index (n=4.5), hexagonal state with low loss (k<0.3) over a wavelength range of 2-10 microns or more. The GSST thickness can be selected to provide pure phase modulation, pure amplitude modulation, or coupled phase and amplitude modulation. GSST can be switched thermally in an oven, optically with visible light, or electrically via Joule heating at speeds from kilohertz to Gigahertz. It operates with reversible and polarization independent transmission switching over a wide incident angle (e.g., 0-60 degrees).

Abstract: State-of-the-art portable Raman spectrometers use discrete free-space optical components that must be aligned well and that don't tolerate vibrations well. Conversely, the inventive spectrometers are made with monolithic photonic integration to fabricate some or all optical components on one or more planar substrates. Photonic integration enables dense integration of components, eliminates manual alignment and individual component assembly, and yields superior mechanical stability and resistance to shock or vibration. These features make inventive spectrometers especially suitable for use in high-performance portable or wearable sensors. They also yield significant performance advantages, including a large (e.g., 10,000-fold) increase in Raman scattering efficiency resulting from on-chip interaction of the tightly localized optical mode and the analyte and a large enhancement in spectral resolution and sensitivity resulting from the integration of an on-chip Fourier-transform spectrometer.

Abstract: Meta-lens based ocular imaging, near-eye display, and eye-tracking systems are described. The systems can include a single focusing optic and an integrated circuit that provides illumination light and includes an imaging array. The focusing optic includes meta-atoms formed on a substrate. The systems may have no moving parts and achieve imaging or image-projection fields-of-view approaching or exceeding 180 degrees. Because of their low part count, the systems can be robust and have a very small form factor.

Abstract: An alloy of GexSbySezTem includes atoms of Ge, Sb, Se, and Te that form a crystalline structure having a plurality of vacancies randomly distributed in the crystalline structure. The alloy can be used to construct an optical device including a first waveguide to guide a light beam and a modulation layer disposed on the first waveguide. The modulation includes the alloy of GexSbySezTem which has a first refractive index n1 in an amorphous state and a second refractive index n2, greater than the first refractive index by at least 1, in a crystalline state. The first waveguide and the modulation layer are configured to guide about 1% to about 50% of the light beam in the modulation layer when the alloy is in the amorphous state and guide no optical mode when the alloy is in the crystalline state.