Abstract: A charged particle track detector includes a radiator including a medium that generates Cherenkov light by interacting with incident charged particles, a light detection unit in which a plurality of two-dimensionally arrayed pixels are disposed to correspond to a predetermined surface of the radiator, and a control unit configured to acquire position information and time information of the plurality of pixels that have detected the Cherenkov light based on a signal output from the light detection unit, and configured to obtain a track of the charged particles based on the acquired position information and the acquired time information, and a propagation locus of the Cherenkov light in the radiator.

Abstract: A coded mask apparatus is provided for gamma rays. The apparatus uses nested masks, at least one of which rotates relative to the other.

Abstract: Disclosed herein are methods and devices for the acquisition of positron emission (or PET) data in the presence of ionizing radiation that causes afterglow of PET detectors. In one variation, the method comprises adjusting a coincidence trigger threshold of the PET detectors during a therapy session. In one variation, the method comprises adjusting a gain factor used in positron emission data acquisition (e.g., a gain factor used to multiply and/or shift the output(s) of a PET detector(s)) during a therapy session. In some variations, a method for acquiring positron emission data during a radiation therapy session comprises suspending communication between the PET detectors and a signal processor of a controller for a predetermined period of time after a radiation pulse has been emitted by the linac.

Abstract: An information presentation system according to the present disclosure makes a presentation unit present each of multiple different pieces of information such that an image displayed in a first form and a sound output in a second form are synchronized with each other on an individual basis. The information presentation system also makes the presentation unit shift, when presenting two different pieces of information, selected from the multiple different pieces of information, as two sounds in the second form, a timing to output one of the two sounds by at least a certain period of time with respect to a timing to output the other of the two sounds, in order to prevent the two sounds from overlapping with each other.

Abstract: Techniques are disclosed relating to the determination of a warping attribute related to a difference between an up-going pressure wavefield and a down-going pressure wavefield received from a seismic data acquisition system. The warping attribute is used to determine a pseudo up-going or down-going pressure wavefield. The pseudo pressure wavefield is used to generate a modified record of geophysical data, which is stored in a non-transitory memory medium as a geophysical data product.

Abstract: A method, apparatus, and program product analyze time-series data such as seismic data collected from a subsurface formation by splitting a time-series data set such as an individual seismic trace into a plurality of spectral components, each having an associated frequency, determining an instantaneous frequency for each spectral component, determining a frequency difference for each spectral component based at least in part on the associated and instantaneous frequencies therefor, and determining a tuning parameter based at least in part on the determined frequency difference of each spectral component. Doing so enables, for example, thin-bed structures in the subsurface formation to be identified, and in some instances, thicknesses of such structures to be determined.

Abstract: A method for acquisition of seismic data in a marine environment.

Abstract: An ultrasonic transducer may comprise a transducer body including a first face and a second face disposed on opposite sides of the transducer body, wherein the transducer body comprises a piezoelectric material; a first transducer edge disposed on the transducer body; and a second transducer edge disposed on the transducer body, wherein the first edge is disposed on the transducer body substantially opposite from the second edge, and wherein the first and second transducer edges intersect a perimeter of the transducer body, and wherein the first and second edge forms an angle no less than 3 degrees.

Abstract: A marine survey system can include a first cable including a first end configured to be coupled to a direct current (DC) power supply on a marine survey vessel and a support module coupled to a second end of the first cable and configured to receive power therefrom. A first electrode of towable electromagnetic (EM) source equipment can be coupled to the support module and configured to receive power therefrom. A depth control device can be coupled to the first electrode and configured to control a depth of the first electrode. A first end of a second cable can be coupled to the support module and configured to receive power therefrom. A second electrode of the towable EM source equipment can be coupled to a second end of the second cable and configured to receive power therefrom.

Abstract: A method and system for downhole, real-time determination of relative permeability with nuclear magnetic resonance and formation testing measurements is provided. The method includes introducing a nuclear magnetic (NMR) tool and a formation testing tool into a well bore penetrating a subterranean formation. The method also includes measuring a saturation of a fluid in the subterranean formation from the NMR tool, measuring a mobility of the fluid from the formation testing tool, and measuring a viscosity of the fluid. The method includes calculating a relative permeability of the subterranean formation based on the measured saturation, the measured viscosity and the measured mobility. The method also includes providing a reservoir production prediction metric based on the calculated relative permeability of the subterranean formation for facilitating a well completion operation in the wellbore.

Abstract: A system includes a metal detector, a structure to hold the metal detector, and a processing unit which processes the measured signal from the metal detector. The measured signals of known objects are recorded with the metal detector. The signals are processed into sets of variables. When an unknown object is detected by the metal detector, the measured signal is processed into the same variables. The variables from the measured signal are compared against the variables in the database. If a match is found, the unknown object is determined.

Abstract: A method of scanning a clothed human subject (14), the method comprising obtaining first scan data using a first scanner (10) by illuminating the subject with a first source of radiation adapted for scanning soft tissue surfaces hidden by the subject's clothing; and obtaining second scan data by illuminating the subject's torso with a second source of radiation (12-1) that is directed more towards the subject's torso than towards other parts of their body, wherein the second source of radiation comprises tissue penetrating radiation.

Abstract: There is provided a method for assigning an attribute to an unknown object overlapping with a predetermined background object. The unknown object is scanned overlapping with the background object within an x-ray scanning device to obtain a plurality of dual-energy attenuation images having attenuation information representing the background object and an overlap region wherein the background object and the unknown object overlap. The dual-energy attenuation images are decomposed into reference material equivalent path length images. The reference material equivalent path lengths representing the background object in the overlap region are determined and eliminated from the overlap region to provide reference material equivalent path length images having first and second reference material equivalent path lengths through only the unknown object.

Abstract: There is provided a method for assigning an attribute to x-ray attenuation including the steps of acquiring first and second reference material equivalent path length information associated with a first range of dual-energy x-ray attenuation information, acquiring second and third reference material equivalent path length information associated with a second range of dual-energy x-ray attenuation information, and, joining the first the first dual-energy x-ray attenuation information range with the second dual-energy x-ray attenuation information range using coefficients representing dual-energy x-ray attenuation information of the second reference material to define a third dual-energy x-ray attenuation information range upon which may be imposed dual-energy x-ray attenuation values within the third dual-energy x-ray attenuation information range to determine corresponding first reference material equivalent path lengths and third reference material equivalent path lengths.

Abstract: A method for assigning one of a safe and threat condition to an object includes determining density and effective atomic number values for a plurality of predetermined safe and threat objects, plotting the values in a probability map to correlate corresponding density and effective atomic number values with each of the safe and threat objects, scanning an object to provide dual-energy attenuation images representing the object, decomposing the attenuation images into dual-reference material equivalent path length images to provide reference material equivalent path lengths representing the object, converting the reference path lengths into object path lengths, determining the effective atomic number for each pixel representing the object, and, imposing the effective atomic number and the mass density of the unknown object onto the probability map to determine a probability that the object is correlated with one of the predetermined safe and threat objects.

Abstract: A vehicle detection system includes a transverse detector arm, two vertical detector arms, a radiation source, a plurality of transverse detectors, and a plurality of vertical detectors. The transverse detector arm may be disposed on the ground. Two vertical detector arms are disposed at both ends of the transverse detector arm. The radiation source is located above the transverse detector arm. A plurality of transverse detectors are disposed within the transverse detector arm and are laid along a length direction of the transverse detector arm for receiving ray emitted by the radiation source. The plurality of vertical detectors are symmetrically disposed on the two vertical detector arms, and each of the vertical detectors is disposed towards a center point of the radiation source for receiving ray emitted by the radiation source.

Abstract: Disclosed is a three-dimensional digital virtual imaging device for stratigraphic texture of borehole core, wherein the probe depth counting pulley is mounted on the lifting wire frame, the output shaft of the motor is configured to drive the reel to rotate, and one end of the cable is connected to the cable transfer node of the retractable reel, the signal input end of the borehole imaging trajectory measuring probe of the on-site imaging host is electrically connected to one end of the cable through the cable transfer node of the retractable reel, the cable is wound on the retractable reel, a retractable line is controlled by the retractable reel, the cable is extended and retracted on the probe depth counting pulley, the probe depth counting pulley records the length of the retractable line of the cable, the depth feedback signal output end of the depth counting pulley is connected to the depth feedback signal input end of the on-site imaging host, the motor control signal output end of the on-site imaging

Abstract: The invention belongs to the field studying the devices for soil and water conservation. The invention involves a topography-meter host based on integrative mainboards, which dynamically observe the landform in real-time and three-dimensions. The linear laser sources are accurately positioned with Ohm-shaped clamps, so as to emit parallel and equidistant laser-planes projecting onto a terrain in an experiment. The positions of the laser-sources on the mainboards are fixed with the Ohm-shaped clamps. The clamps do not only realize the convenient adjustment of the emission angle and spacing distance of the adjacent laser-sources, but also ensure a high accuracy of the positions and angles of the laser-sources even if the topography-meter host is moved. Several multi-segmented cases are freely spliced to observe the landforms with different heights in real-time.

Abstract: A system and method for modeling a geological structure may include, in an initial model, computing a first function for a geological structure including a first set of iso-surfaces. A processor may detect if the first set of iso-surfaces intersect a set of geological markers within a threshold proximity. If not, the initial model may be corrected using an induced mesh having an increased cell resolution compare to the initial model for computing a second function for the geological structure including a second set of iso-surfaces that intersect the geological markers within the threshold proximity. A processor may insert the second set of iso-surfaces into a second model to locally increase its resolution relative to the initial model by dividing cells in the second model along the second set of iso-surfaces. For each new geological structure, the above steps may be repeated using the second model as the initial model.

Abstract: A wind flow sensing system determines a first approximation of the velocity field at each of the altitudes by simulating computational fluid dynamics (CFD) of the wind flow with operating parameters reducing a cost function of a weighted combination of errors, determines a horizontal derivative of vertical velocity at each of the altitudes from the first approximation of the velocity fields, and determines a second approximation of the velocity fields using geometric relationships between a velocity field for each of the altitudes, projections of the measurements of radial velocities on the three-dimensional axes, and the horizontal derivative of vertical velocity for the corresponding velocity field. In the cost function of the CFD, each error corresponds to one of the altitudes and includes a difference between measured velocities at the line-of-site points at the corresponding altitude and simulated velocities at the line-of-site points simulated by the CFD for the corresponding altitude.

Abstract: A distributed weather system includes a storage, a plurality of wireless weather stations, a server, and an interface. Each of the plurality of wireless weather stations is associated with a user and has a battery, a location sensor generating location information, an anemometer generating apparent wind speed, a transmitter transmitting the location information with the apparent wind speed to a network at periodic intervals, and a receiver receiving control commands that include a length of the periodic intervals. The server receives the location information with the apparent wind speed and stores them in the storage. The interface is accessible by a mobile computer, and receives the control commands from a user and sends them to the receiver of the wireless weather station associated with the user. The interface displays a true wind speed for each of the plurality of wireless weather stations, which is calculated using the apparent wind speed, the location information, and historical location information.

Abstract: Techniques for local weather forecast using a local weather forecast model are described herein. The disclosed techniques include generating data indicative of future weather conditions for a plurality of locations based at least on future forecast data provided by an existing forecast provider and a correlation between data collected by a plurality of data collection devices and historical data provided by the existing forecast provider. The disclosed techniques also include temporally and spatially interpolating the generated data and obtaining higher-frequency future weather forecast data for the plurality of locations and local weather forecast data for other locations than the plurality of locations.

Abstract: The invention provides a material for contact lenses, including a first siloxane macromer shown as formula (I): in formula (I), R1, R2 and R3 are C1-C4 alkyl groups, R4 is C1-C6 alkyl group, R5 is C1-C4 alkylene group, R6 is —OR7O— or —NH—, R7 and R8 are C1-C4 alkylene groups and m is an integer of about 1-2, n is an integer of about 4-80; a second siloxane macromer shown as formula (II): in formula (II), R9, R10 and R11 are C1-C4 alkyl groups, R12, R13 and R15 are C1-C3 alkylene group, R14 is a residue obtained by removing NCO group from an aliphatic or aromatic diisocyanate, and o is an integer of about 4-80, p is an integer of about 0-1; q is an integer of about 1-20; at least one hydrophilic monomer and an initiator.

Abstract: A hydrophilic siloxane copolymer of siloxane and hydrophilic organic monomer/s The copolymers can be functionalized to make them capable of undergoing further polymerization by thermal or actinic radiations. The hydrophilicity of these polymers can be varied by varying the siloxane versus organic monomer ratio thereby going from water dispersible to soluble states. The siloxane content can be tuned accordingly in order to provide moderate to high oxygen permeability. These copolymers can be used as a single component curable composition which results in hydrogels to minimize the presence of leachable components thus by reducing the processing cost. The polymers may also find applications in personal care formulations as copolymers, film-formers, hydrogels, coating, emulsions/latex etc.

Abstract: Ultra thin Fresnel lenses and methods of forming the same are described herein. An optical element comprising an ultra thin Fresnel lens includes a plurality of Fresnel elements formed on a surface of a substrate. Each of the plurality of Fresnel surface elements has an angled facet portion and a shallow or substantially horizontal portion. The Fresnel surface elements can be formed, for example, by a hot stamp or cold transfer method.

Abstract: This invention provides a vision system that is arranged to compensate for optical drift that can occur in certain variable lens assemblies, including, but not limited to, liquid lens arrangements. The system includes an image sensor operatively connected to a vision system processor, and a variable lens assembly that is controlled (e.g. by the vision processor or another range-determining device) to vary a focal distance thereof. A positive lens assembly is configured to weaken an effect of the variable lens assembly over a predetermined operational range of the object from the positive lens assembly. The variable lens assembly is located adjacent to a front or rear focal point of the positive lens. The variable lens assembly illustratively comprises a liquid lens assembly that can be inherently variable over approximately 20 diopter. In an embodiment, the lens barrel has a C-mount lens base.

Abstract: Light redirecting film articles include a microstructured optical film, such as a daylight redirecting film, bonded to another film. This type of assembly may serve various purposes. For example, the assembly may protect the structured film, provide additional functionality, such as diffusion or infrared reflection, and/or facilitate attachment of the microstructured optical film to a mounting surface, such as a glazing or window pane.

Abstract: A system and method are provided for forming one-way light transmissive layers implementing optical light scattering techniques in those layers, and to objects, object portions, lenses, filters, screens and the like that are formed of, or that otherwise incorporate, such one-way light transmissive layers. Processes are provided by which to form, or otherwise incorporate, one or more one-way light transmissive, or substantially transparent, object portions or layers in solid or hollow objects Individual one-way light transmissive layers are formed of substantially-transparent sub-micrometer spheres, including micro-particles and/or nano-particles, with nano-voids incorporated between them.

Abstract: A transflective and non-rectangular display panel and a display device are provided. The non-rectangular display panel includes a display region, a non-display region surrounding the display region, multiple pixels including multiple sub pixels, and a light shielding layer. There is a first boundary between the display region and the non-display region, and a region surrounded by the first boundary and the display region is non-rectangular. Each of the multiple pixels includes at least three of the multiple sub pixels. An open region of each of the multiple sub pixels has a transmissive region and a reflective region. The multiple pixels include normal pixels in the display region and abnormal pixels passed through by the first boundary. In each of the abnormal pixels, each of the transmissive region and the reflective region is partially blocked by the light shielding layer and partially emits light therefrom.

Abstract: The present disclosure, belonging to the field of display technology, provides a grating assembly, a light source apparatus and a driving method thereof, which can solve a problem that an existing light source cannot provide light with a controllable direction. The grating assembly of the present disclosure comprises: a diffraction grating divided into a plurality of sub-pixels, each sub-pixel being divided into a plurality of regions, the diffraction grating being configured to change light transmitted through each region into parallel light and cause light transmitted through different regions of a same sub-pixel to have different directions; and a selector divided into a plurality of sub-pixels corresponding to sub-pixels of the diffraction grating, each sub-pixel being divided into a plurality of regions corresponding to the regions of the sub-pixel of the diffraction grating, the selector being configured to control whether each region thereof transmits light or not.

Abstract: A solar-radiation-shielding material for vehicle windows reduces the visible light transmittance, and reduces the value of solar radiation transmittance/visible light transmittance. The visible light transmittance of the solar-radiation-shielding material is in the range of 5%. The transmission color of the solar-radiation-shielding material satisfies the Expression 2: ?14<a*<2, and ?8<b*<2.

Abstract: An infrared-cut filter (1a) includes a near-infrared reflecting film (20) and an absorbing film (30). The near-infrared reflecting film (20) and the absorbing film (30) have the following features (A) to (E); (A) 700 nm??HR (0°, 70%)<?HR (0°, 20%)?770 nm; (B) 650 nm??HR (40°, 70%)<?HR (40°, 20%)?720 nm; (C) ?HA (40°, 20%)<?HR (40°, 20%); (D) the spectral transmittance of light incident on the absorbing film (30) is 15% or less at ?HR (0°, 20%) and ?HR (40°, 20%); and (E) an average of the spectral transmittance of light incident on the near-infrared reflecting film (20) and an average of the spectral transmittance of light incident on the absorbing film (30) are 75% or more in the wavelength range of 450 to 600 nm.

Abstract: A confocal optical system-based measurement apparatus includes: a light source; a light projecting optical fiber group; a light receiving optical fiber group; a spectroscope; and a confocal optical system configured to condense each of a plurality of beams from a plurality of light projecting optical fibers to irradiate a sample therewith, and cause a plurality of beams from a plurality of condensing points on the sample to form images on the plurality of light receiving optical fibers, respectively, wherein the light projecting optical fiber group includes the plurality of light projecting optical fibers configured to receive light from the light source, the light receiving optical fiber group includes the plurality of light receiving optical fibers configured to guide received light to the spectroscope, the shape of an end face of the light projecting optical fiber group and the shape of an end face of the light receiving optical fiber group are in a mirror image relationship, and in the light projecting op

Abstract: A vehicle badge includes a base and a circuit board disposed on the base. A plurality of light sources is disposed on the circuit board. The plurality of light sources defines a pattern. A guide member is disposed over the plurality of light sources. The guide member defines a plurality of light guides. A housing has a viewable portion and is disposed over the guide member. The guide member directs light from the plurality of light sources to the housing. A controller is operably coupled to each light source of the plurality of light sources. The controller selectively illuminates each light source of the plurality of light sources.

Abstract: A light guide plate includes a body region and a light incident region. The body region has a light exiting surface, an opposite base surface, and a side surface between the light exiting surface and the base surface. The light incident region is located at the side surface of the body region for receiving incident light and includes projections protruding outwards from the side surface of the body region, and a cavity is defined between adjacent projections. Each projection has a top surface and outer side walls. The outer side walls also define inner side walls of each cavity together with a bottom surface. The top surface, side walls, and bottom surface together are a light incident surface of the light incident region. An angle between the top surface and each outer side wall is called an apex angle, which is greater than 90 degrees.

Abstract: Provided are a backlight unit and a holographic display apparatus including the same. The backlight unit includes a light guide plate; an input coupler configured to guide light into the light guide plate; a light deflector configured to deflect light emitted from the input coupler and guide the deflected light to propagate within the light guide plate. The light deflector is disposed on a region of the light guide plate which does not overlap with an optical path of light incident on the input coupler. The backlight unit also includes an output coupler configured to emit the light, having been propagated within the light guide plate, to an outside of the light guide plate.

Abstract: A solid-state luminaire module includes one or more light-emitting elements (LEEs) arranged to provide light; and a light guide including a receiving end arranged to receive the light provided by the LEEs and an opposing end, a pair of opposing side surfaces extending along a length of the light guide to guide the received light in a forward direction to the opposing end, and a redirecting end-face located at the opposing end and configured to reflect the guided light—that reaches the opposing end—back into the light guide as return light, such that substantially all the return light impinges on the pair of opposing side surfaces at incident angles larger than a critical incidence angle and transmits through the pair of opposing side surfaces into the ambient as output light of the luminaire module, the output light to propagate in backward directions.

Abstract: An optical chamber, an optical system, and a display device are provided. The optical chamber includes: a plurality of sidewalls, including a first sidewall having at least one opening, configured to reflect light in the optical chamber; and a light path adjusting element connected with the first sidewall, wherein the orthographic projection of the light path adjusting element onto the plane where the first sidewall lies at least partially lies in the area where the opening is located, and the light path adjusting element is configured to uniformly emit the light reflected by the plurality of sidewalls to the outside.

Abstract: The present invention provides a light guide plate having a light exit surface, a light incident surface and a bottom surface. In the said light guide plate, the bottom surface is opposite to the light exit surface, and the light incident surface connects the light exit surface and the bottom surface. A plurality of light guide structures are formed on the bottom surface, and each of the light guide structure includes a front mound protruding above the bottom surface, a back mound protruding above the bottom surface and located at the side of the front mound opposite to the light incident surface, and a concave eye-shaped portion caved in from the bottom surface and located between the front mound and the back mound.

Abstract: A backlight assembly includes an optical plate, a light source provided near the optical plate, and a brightness redistribution film provided above the optical plate. When light emitted from the light source passes through the optical plate and the brightness redistribution film, a front view angle brightness measured in a normal direction of a light exiting surface of the brightness redistribution film relative to a maximum brightness emitted from the backlight assembly has a brightness ratio N, wherein the brightness ratio N is greater than or equal to 60% and is smaller than 100% (60%?N<100%).

Abstract: Backlight module and display device are provided. The backlight module includes an accommodation frame including a base and an extending part, a first light guide plate, a second light guide plate; a first reflector, a first light source, and a second light source. The first light guide plate and the second light guide plate are disposed sequentially along a direction perpendicular to a plane of the base in an accommodation space formed by the base and the extending part, and are controlled independently. The first light source has a wavelength ?1 of 780 nm<?1?1310 nm, and the second light source has a wavelength ?2 of 380 nm??2?780 nm. A reflectivity of the first reflector on light emitted by the second light source is larger than a reflectivity of the first reflector on light emitted by the first light source.

Abstract: An LED strip assembly for a light fixture includes a PCB strip and a power connector electrically connected thereto. A rear of the PCB strip is mounted to a support wall of a frame of the light fixture and LEDs are mounted to a front of the PCB strip. The power connector includes a connector housing having a contact cavity and a mounting tab configured to be mounted to the support wall of the frame of the light fixture. The power connector includes a power wire assembly coupled to the connector housing having a power wire and a power wire contact terminated thereto. The power wire contact has a spring beam mechanically and electrically connected to a power pad of the PCB strip at a separable mating interface to electrically connect the power wire to a power circuit of the PCB strip.

Abstract: A display apparatus includes a display panel, a light guide plate disposed behind the display panel, the light guide plate being lengthwise or widthwise smaller than the display panel, a light source disposed adjacent to a first lateral surface of the light guide plate and irradiates light onto the first lateral surface, a back chassis disposed behind the light guide plate and supports a back surface of the light guide plate and a support structure disposed along a second lateral surface of the light guide plate different from the first lateral surface of the light guide plate. Further, the support structure includes light blocking protrusion that blocks a portion of the second lateral surface.

Abstract: In one example, an optical device may include a waveguide having a core index of refraction that decreases along a length of the waveguide and an edge index of refraction of the waveguide that is constant along the length of the waveguide. The central rays of the optical signals travelling through the waveguide may be refracted towards higher radii while the outer rays propagate unaffected. The optical device may decrease dispersion of the optical signals travelling through an optical fiber.

Abstract: An optical subassembly includes a planar dielectric waveguide structure that is deposited at temperatures below 400 C. The waveguide provides low film stress and low optical signal loss. Optical and electrical devices mounted onto the subassembly are aligned to planar optical waveguides using alignment marks and stops. Optical signals are delivered to the submount assembly via optical fibers. The dielectric stack structure used to fabricate the waveguide provides cavity walls that produce a cavity, within which optical, optoelectronic, and electronic devices can be mounted. The dielectric stack is deposited on an interconnect layer on a substrate, and the intermetal dielectric can contain thermally conductive dielectric layers to provide pathways for heat dissipation from heat generating optoelectronic devices such as lasers.

Abstract: An optical receiver may include a planar lightwave circuit with an optical path and a tapered reflection surface to direct an optical beam toward a top surface of the planar lightwave circuit. The optical receiver may include a photodiode disposed onto the top surface of the planar lightwave circuit such that a receive portion of the photodiode is aligned to the optical path, wherein a gap between the photodiode and the planar lightwave circuit is less than 5 microns.

Abstract: A method for measuring and dynamically modulating characteristics of slow light in a photonic-crystal coupled-cavity waveguide is set forth. A photonic-crystal structure consists of a series of microcavity components formed by arranging silicon dielectric rods in triangular lattice structure in the substrate of organic polymer polystyrene with an electro-optical effect, a light waveguide structure being along the X direction, and regularly removing single silicon dielectric rods. The present disclosure has the beneficial effects that extremely high slow light effect and high-performance all-optical buffer are realized.

Abstract: Structures that include a Bragg grating and methods of fabricating a structure that includes a Bragg grating. Bragg elements are positioned adjacent to a waveguide. The Bragg elements are separated by grooves that alternate with the Bragg elements. A dielectric layer includes portions positioned to close the grooves to define airgaps. The airgaps are respectively arranged between adjacent pairs of the Bragg elements. The Bragg elements may be used to form the Bragg grating.

Abstract: Structures for a directional coupler and methods of fabricating a structure for a directional coupler. A first section of a first waveguide core is laterally spaced from a second section of a second waveguide core. A coupling element is arranged either over or under the first section of the first waveguide core and the second section of the second waveguide core. The first and second waveguide cores are comprised of a material having a first refractive index, and the first coupling element is comprised of a material having a second refractive index that is different from the first refractive index. The first coupling element is surrounded by a side surface that overlaps with the first section of the first waveguide core and the second section of the second waveguide core.

Abstract: A hybrid grating comprises a first grating layer composed of a first solid-state material, and a second grating layer over the first grating layer and composed of a second solid-state material, the second solid state-material being different than the first solid-state material and having a monocrystalline structure.