Abstract: Low loss fiber-to-chip interfaces for lithium niobate photonic integrated circuits are provided. An optical circuit includes a waveguide comprising an electro-optical material. The waveguide includes an elevated ridge and a slab underlying the elevated ridge, the elevated ridge and the slab extending along a central axis toward an optical interface. The elevated ridge and the slab each have a plurality of cross-sections along the central axis, each cross-section having a width measured perpendicular to the central axis, wherein the width of elevated ridge is smaller than the width of the slab for every cross-section along the central axis. The elevated ridge includes a tapered portion having a first taper, wherein the cross-section of the elevated portion decreases along the central axis toward the optical interface. The slab includes a tapered portion having a second taper, wherein the cross-section of the slab decreases along the central axis toward the optical interface.

Abstract: Systems and methods are disclosed for making a quantum network node. A plurality of scoring function F values are calculated for an array of at least two photonic crystal cavity unit cells, each having a lattice constant ? and a hole having a length Hx and a width Hy. A value of ?, a value of Hx, and a value of Hy are selected for which a scoring function value is at a maximum. A waveguide region and the array of at least two photonic crystal cavity unit cells based on the selected values are formed on a substrate. At least one ion between a first photonic crystal cavity unit cell and a second photonic crystal cavity unit cell are implanted and annealed into a quantum defect. A coplanar microwave waveguide is formed on the substrate in proximity to the array of at least two photonic crystal cavity unit cells.

Abstract: A terahertz device for detecting or emitting or for both detecting and emitting electromagnetic waves in the terahertz frequency range. The terahertz device comprises: a first waveguide branch and a second waveguide branch, the first and second waveguide branches being configured to allow optical signals to propagate through them, the first and second waveguide branches being nonlinear dielectric elements with a thickness of at most 500 micrometres; and an antenna arrangement comprising a set of antennas for capturing and/or emitting electromagnetic waves in the terahertz frequency range, the antennas being placed along at least one of the waveguide branches in an immediate vicinity of the respective waveguide branch and/or around the respective waveguide branch to at least partially enclose the respective waveguide branch in a respective antenna gap of the respective antenna.

Abstract: Systems and methods are disclosed for making a quantum network node. A plurality of scoring function F values are calculated for an array of at least two photonic crystal cavity unit cells, each having a lattice constant a and a hole having a length Hx and a width Hy. A value of a, a value of Hx, and a value of Hy are selected for which a scoring function value is at a maximum. A waveguide region and the array of at least two photonic crystal cavity unit cells based on the selected values are formed on a substrate. At least one ion between a first photonic crystal cavity unit cell and a second photonic crystal cavity unit cell are implanted and annealed into a quantum defect. A coplanar microwave waveguide is formed on the substrate in proximity to the array of at least two photonic crystal cavity unit cells.

Abstract: A multi-layered lens comprises a plurality of metasurface layers. At least some layers of the plurality of metasurface layers include features that exhibit angular phase controls. The angular phases of the at least some layers cause an angular aberration correction or an angle convergence that focuses light onto a focal point regardless of angles of incidence.

Abstract: Kerr and electro-optic frequency comb generation in integrated lithium niobate devices is provided. In various embodiments, a microring resonator comprising lithium niobate is disposed on a thermal oxide substrate. The microring resonator has inner and outer edges. Electrodes are positioned along the inner and outer edges of the microring resonator. The electrodes are adapted to modulate the refractive index of the microring. A pump laser is optically coupled to the microring resonator. The microring resonator is adapted to emit an electro-optical frequency comb when receiving a pump mode from the pump laser and when the electrodes are driven at a frequency equal to a free-spectral-range of the microring resonator.

Abstract: Sources of shaped single photons based on an integrated diamond nanophotonic system are provided.

Abstract: Optical devices and their fabrication from thin film lithium niobate are provided. In some embodiments, an optical device includes a substrate and an optical waveguide disposed on the substrate. The optical waveguide comprises lithium niobate. The optical waveguide has a central ridge extending laterally along the substrate. A pair of electrodes is disposed on opposite sides of the central ridge of the optical waveguide.

Abstract: Optical devices and their fabrication from thin film lithium niobate are provided. In some embodiments, an optical device includes a substrate and an optical waveguide disposed on the substrate. The optical waveguide comprises lithium niobate. The optical waveguide has a central ridge extending laterally along the substrate. A pair of electrodes is disposed on opposite sides of the central ridge of the optical waveguide.

Abstract: Kerr and electro-optic frequency comb generation in integrated lithium niobate devices is provided. In various embodiments, a microring resonator comprising lithium niobate is disposed on a thermal oxide substrate. The microring resonator has inner and outer edges. Electrodes are positioned along the inner and outer edges of the microring resonator. The electrodes are adapted to modulate the refractive index of the microring. A pump laser is optically coupled to the microring resonator. The microring resonator is adapted to emit an electro-optical frequency comb when receiving a pump mode from the pump laser and when the electrodes are driven at a frequency equal to a free-spectral-range of the microring resonator.

Abstract: Kerr and electro-optic frequency comb generation in integrated lithium niobate devices is provided. In various embodiments, a microring resonator comprising lithium niobate is disposed on a thermal oxide substrate. The microring resonator has inner and outer edges. Electrodes are positioned along the inner and outer edges of the microring resonator. The electrodes are adapted to modulate the refractive index of the microring. A pump laser is optically coupled to the microring resonator. The microring resonator is adapted to emit an electro-optical frequency comb when receiving a pump mode from the pump laser and when the electrodes are driven at a frequency equal to a free-spectral-range of the microring resonator.

Abstract: Devices for determining a state of a magnetic field-generating article are provided. In various embodiments, a device comprises: a single crystal diamond having a plurality of NV centers, the single crystal diamond configured to be disposed adjacent to a magnetic field-generating article, and configured to generate a fluorescent signal in response to being illuminated by a light source; a coherent light source configured to generate a light beam directed at the single crystal diamond; a microwave (MW) radiation source configured to irradiate the single crystal diamond with a MW signal; a magnetic field source configured to apply a bias magnetic field to the single crystal diamond; a photosensor configured to collect the fluorescent signal generated by the single crystal diamond; and a computing node operatively coupled to each of the coherent light source, the MW radiation source, the magnetic field source, and the photosensor.

Abstract: An optical structure having enhanced optical properties, the optical structure comprising a bulk homogenous substrate that is surface modified so as to provide the enhanced optical properties. Surface modification of the bulk homogenous substrate can comprise removing portions of the bulk homogenous substrate to provide nanostructure elements at the surface, thereby providing an improved optical structure formed of a homogenous material. Methods for enhancing the optical properties of a bulk homogenous substrate include surface modifying the bulk homogenous substrate to provide an optical structure formed of a homogenous material, the optical structure having enhanced optical properties compared to the unmodified bulk homogenous material.

Abstract: Electro-optic devices for classical and quantum microwave photonics are provided. In various embodiments, a device comprises: a waveguide; a first ring resonator; a second ring resonator, the second ring resonator evanescently coupled to the first ring resonator and to the waveguide; a first pair of electrodes, one of the first pair of electrodes disposed within the first ring resonator and the other of the first pair of electrodes disposed without the first ring resonator; a second pair of electrodes, one of the second pair of electrodes disposed within the second ring resonator and the other of the second pair of electrodes disposed without the second ring resonator; a microwave source electrically coupled to the first and second pairs of electrodes; a bias port electrically coupled to the first and second pairs of electrodes and configured to sweep a frequency band.

Abstract: Systems and methods are disclosed for making a quantum network node. A plurality of scoring function F values are calculated for an array of at least two photonic crystal cavity unit cells, each having a lattice constant a and a hole having a length Hx and a width Hy. A value of a, a value of Hx, and a value of Hy are selected for which a scoring function value is at a maximum. A waveguide region and the array of at least two photonic crystal cavity unit cells based on the selected values are formed on a substrate. At least one ion between a first photonic crystal cavity unit cell and a second photonic crystal cavity unit cell are implanted and annealed into a quantum defect. A coplanar microwave waveguide is formed on the substrate in proximity to the array of at least two photonic crystal cavity unit cells.

Abstract: In a general aspect, a photonic quantum network is disclosed. In some implementations, microwave modes and optical modes are generated on first and second quantum processing units (QPUs) by operation of a first transducer device of the first QPU and a second transducer device of the second QPU. The microwave modes are transmitted within the first and second QPUs from the first and second transducer devices to respective first and second qubit devices. The optical modes are transmitted from the first and second QPUs to an interferometer device. By operation of the interferometer device, output signals are generated on respective output channels based on the optical modes from the first and second QPUs. Based on the output signals detected by operation of photodetector devices coupled to the respective output channels, quantum entanglement transferred to the first and second qubit devices by the microwave modes is identified.

Abstract: Low loss fiber-to-chip interfaces for lithium niobate photonic integrated circuits are provided. An optical circuit includes a waveguide comprising an electro-optical material. The waveguide includes an elevated ridge and a slab underlying the elevated ridge, the elevated ridge and the slab extending along a central axis toward an optical interface. The elevated ridge and the slab each have a plurality of cross-sections along the central axis, each cross-section having a width measured perpendicular to the central axis, wherein the width of elevated ridge is smaller than the width of the slab for every cross-section along the central axis. The elevated ridge includes a tapered portion having a first taper, wherein the cross-section of the elevated portion decreases along the central axis toward the optical interface. The slab includes a tapered portion having a second taper, wherein the cross-section of the slab decreases along the central axis toward the optical interface.

Abstract: Optical devices and their fabrication from thin film lithium niobate are provided. In some embodiments, an optical device includes a substrate and an optical waveguide disposed on the substrate. The optical waveguide comprises lithium niobate. The optical waveguide has a central ridge extending laterally along the substrate. A pair of electrodes is disposed on opposite sides of the central ridge of the optical waveguide.

Abstract: Reconfigurable electro-optic frequency shifters are provided. In various embodiments, the optical frequency shifter comprises a continuous optical spectrum medium; a discrete optical spectrum medium optically coupled to the continuous optical spectrum medium; and a tunable element operably coupled to the discrete optical spectrum medium, wherein: the discrete optical spectrum medium has N optical modes (I:{i1 . . . iN}), said optical modes being ordered and equidistant in a frequency domain, wherein N is an integer equal to or greater than 3, each of the optical modes (in?I) having a coupling constant ?e,n with respect to the continuous optical spectrum medium, wherein at least one of the coupling constants ?e,n is different from the other coupling constants, the optical modes (I) having a coupling constant ? with respect to one another, wherein the tunable element is configured to control the coupling constant ?.

Abstract: Devices for determining a state of a magnetic field-generating article are provided. In various embodiments, a device comprises: a single crystal diamond having a plurality of NV centers, the single crystal diamond configured to be disposed adjacent to a magnetic field-generating article, and configured to generate a fluorescent signal in response to being illuminated by a light source; a coherent light source configured to generate a light beam directed at the single crystal diamond; a microwave (MW) radiation source configured to irradiate the single crystal diamond with a MW signal; a magnetic field source configured to apply a bias magnetic field to the single crystal diamond; a photosensor configured to collect the fluorescent signal generated by the single crystal diamond; and a computing node operatively coupled to each of the coherent light source, the MW radiation source, the magnetic field source, and the photosensor.