Abstract: A sensor includes a light emitter capable of producing stimulated emission. The sensor includes an optical fiber comprising at least one fiber Bragg grating. A first end of the optical fiber is optically coupled to a first emitting end of the light emitter. The fiber Bragg grating is located at a measurement region of the optical fiber away from the first end. A change in wavelength of the laser emission in the optical fiber is induced by a change in peak reflectivity of the fiber Bragg grating. The change in the peak reflectivity occurs in response to an environmental change at the measurement region, e.g., which changes a physical periodicity and/or the refractive index of the grating. The sensor includes an optical detector coupled to the optical fiber or the light emitter that detects the change in the wavelength.

Abstract: A machine vision system and method uses photoluminescence light response of micro-LEDs to identify micro-LEDs (e.g., red, green, or blue) that are used to assemble a micro-LED display. Excitation light (e.g., ultraviolet excitation light) in a wavelength range is illuminated on a random pool of heterogeneous micro-LEDs consisting of materials, for example, that photoluminesce in three different colors-red, green, or blue. The micro-LED is optically excited and will emit either red, green, or blue, photoluminescence light based on the type of the micro-LED. The machine vision system uses a camera device including color response sensors to distinguish micro-LED types. The orientation of the micro-LED can also be detected. The machine vision system, based on the type, location, and orientation of the heterogeneous micro-LEDs, provides image-data based optical feedback to a microassembler system to move the micro-LEDs on a planar working surface according to an electrostatic template.

Abstract: A light emitting diode (LED) array includes bottom reflectors patterned as an array of closed shapes on a top plane of a base layer for III-N growth. A three-dimensional III-N structure is epitaxially grown around the array of closed shapes and extending above the bottom reflectors. The three-dimensional III-N structures is a contiguous crystalline structure extending across the array. A laterally grown III-N layer is formed in contact with both the reflectors and the three-dimensional III-N structures, and III-N LED layers are grown on the laterally grown layer. One or more top reflectors are grown or deposited on the III-N LED layers and located over the bottom reflectors.

Abstract: A machine vision system and method uses photoluminescence light response of micro-LEDs to identify types of micro-LEDs (e.g., red, green, or blue) that are used to assemble a micro-LED display. Excitation light (e.g., ultraviolet excitation light) in a certain wavelength range is illuminated on a random pool of heterogeneous micro-LEDs consisting of materials, for example, that photoluminesce in three different colors-red, green, or blue. The micro-LED is optically excited and will emit either red, green, or blue, photoluminescence light based on the type of the micro-LED. The machine vision system uses a camera device that includes color response sensors to differentiate the type of micro-LED. The orientation of the micro-LED can also be detected. The machine vision system, based on the type, location, and orientation of the heterogeneous micro-LEDs, provides image-data based optical feedback to a microassembler system to move the micro-LEDs on a planar working surface according to an electrostatic template.

Abstract: A machine vision system and method uses photoluminescence light response of micro-LEDs to identify types of micro-LEDs (e.g., red, green, or blue) that are used to assemble a micro-LED display. Excitation light (e.g., ultraviolet excitation light) in a certain wavelength range is illuminated on a random pool of heterogeneous micro-LEDs consisting of materials, for example, that photoluminesce in three different colors-red, green, or blue. The micro-LED is optically excited and will emit either red, green, or blue, photoluminescence light based on the type of the micro-LED. The machine vision system uses a camera device that includes color response sensors to differentiate the type of micro-LED. The orientation of the micro-LED can also be detected. The machine vision system, based on the type, location, and orientation of the heterogeneous micro-LEDs, provides image-data based optical feedback to a microassembler system to move the micro-LEDs on a planar working surface according to an electrostatic template.

Abstract: A mask material is deposited on a substrate or growth template. The substrate or growth template is compatible with crystalline growth of a crystalline optical material. Patterned portions of the mask material are removed to expose one or more regions of the substrate or growth template. The one or more regions have target shapes of one or more optical components. The crystalline optical material is selectively grown in the one or more regions to form the one or more optical components.

Abstract: A mask material is deposited on a substrate or growth template. The substrate or growth template is compatible with crystalline growth of a crystalline optical material. Patterned portions of the mask material are removed to expose one or more regions of the substrate or growth template. The one or more regions have target shapes of one or more optical components. The crystalline optical material is selectively grown in the one or more regions to form the one or more optical components.

Abstract: A sensor includes a light emitter capable of producing stimulated emission. The sensor includes an optical fiber comprising at least one fiber Bragg grating. A first end of the optical fiber is optically coupled to a first emitting end of the light emitter. The fiber Bragg grating is located at a measurement region of the optical fiber away from the first end. A change in wavelength of the laser emission in the optical fiber is induced by a change in peak reflectivity of the fiber Bragg grating. The change in the peak reflectivity occurs in response to an environmental change at the measurement region, e.g., which changes a physical periodicity and/or the refractive index of the grating. The sensor includes an optical detector coupled to the optical fiber or the light emitter that detects the change in the wavelength.

Abstract: A mask material is deposited on a substrate or growth template. The substrate or growth template is compatible with crystalline growth of a crystalline optical material. Patterned portions of the mask material are removed to expose one or more regions of the substrate or growth template. The one or more regions have target shapes of one or more optical components. The crystalline optical material is selectively grown in the one or more regions to form the one or more optical components.

Abstract: A light emitting diode array includes a growth mask having an array of closed shapes on a III-N layer. An array of group III-N inverted pyramids are epitaxially grown around the growth mask. The inverted pyramids include {10-11} or {11-22} facets and hexagonal bases. An array of III-N c-plane surfaces are parallel with the substrate and join the {10-11} or {11-22} facets of adjacent ones of the III-N inverted pyramids. A quantum well layer of a III-N compound is formed on the {10-11} or {11-22} facets and the c-plane surfaces. The quantum well layer has a first thickness on the {10-11} or {11-22} facets that forms first light emitting elements. The quantum well layer has a second thickness on the c-plane surfaces that forms second light emitting elements. The second light emitting elements emit light at a longer wavelength than the first light emitting elements.

Abstract: A semiconductor device is formed on a bulk substrate of n-type GaN. The semiconductor device has a material layer grown on the bulk substrate. A first surface of the bulk substrate facing away from the material layer is mechanically roughened and a negative electrical contact is formed on the roughened surface using a low work function metal.

Abstract: Ink-based digital printing systems useful for ink printing include a rotatable charge-retentive reimageable surface layer configured to receive a layer of fountain solution. The fountain solution is carried to the charge retentive surface by a fog or mist including fountain solution aerosol particles, dispersed gas particles, and charge directors that impart charge to the fountain solution aerosol particles. The charge-retentive reimageable surface may be charged to a uniform potential, and selectively discharged using an ROS according to image data to form an electrostatic latent image. The charged fountain solution adheres to portions of the charge-retentive reimageable surface according to the electrostatic latent image to form a fountain solution image thereon. The fountain solution image can be partially transferred to an imaging blanket, where the fountain solution image is inked. The resulting ink image may be transferred to a print substrate.

Abstract: A light emitting diode (LED) array includes bottom reflectors patterned as an array of closed shapes on a top plane of a base layer for III-N growth. A three-dimensional III-N structure is epitaxially grown around the array of closed shapes and extending above the bottom reflectors. The three-dimensional III-N structures is a contiguous crystalline structure extending across the array. A laterally grown III-N layer is formed in contact with both the reflectors and the three-dimensional III-N structures, and III-N LED layers are grown on the laterally grown layer. One or more top reflectors are grown or deposited on the III-N LED layers and located over the bottom reflectors.

Abstract: A transistor includes a first layer comprising a group III-nitride semiconductor. A second layer comprising a group III-nitride semiconductor is disposed over the first layer. A third layer comprising a group III-nitride semiconductor is disposed over the second layer. An interface between the second layer and the third layer form a polarization heterojunction. A fourth layer comprising a group III-nitride semiconductor is disposed over the third layer. An interface between the third layer and the fourth layer forms a pn junction. A first electrical contact pad is disposed on the fourth layer. A second electrical contact pad is disposed on the third layer. A third electrical contact pad is electronically coupled to bias the polarization heterojunction.

Abstract: An apparatus includes an epitaxial structure comprising a bottom layer, channel walls formed on the bottom layer, and a top layer that encloses the channel walls and forms microchannels therebetween. The bottom layer, channel walls, and covering layer are a monolithic, crystalline formation. An electronic or optoelectronic device is monolithically formed on a first build surface of the bottom layer or the top layer. The electronic or optoelectronic device is energy-coupled to the microchannels through the bottom layer or the top layer.

Abstract: Based on evaporation of fountain solution from a rotating blanket cylinder to create an image that may be inked and printed, a digitally addressable heater array at or just below the blanket surface evaporates deposited fountain solution and forms a fountain solution latent image on the surface. The heater array has controllable heating elements (e.g., field effect transistors, thin film transistors) that provide a transient heat pattern on the surface to evaporate the fountain solution. Heat is generated by current flow in the heating elements, and power developed by the heating circuit is the product of source-drain voltage and current in the channel. Current may be supplied along data lines by an external voltage controlled by digital electronics to provide the desired heat at heating elements addressed by a specific gate line. The heater array may include a current return line that may be a 2-dimensional mesh.

Abstract: A mask material is deposited on a substrate or growth template. The substrate or growth template is compatible with crystalline growth of a crystalline optical material. Patterned portions of the mask material are removed to expose one or more regions of the substrate or growth template. The one or more regions have target shapes of one or more optical components. The crystalline optical material is selectively grown in the one or more regions to form the one or more optical components.

Abstract: Based on evaporation of fountain solution from a rotating blanket cylinder to create an image that may be inked and printed, a digitally addressable heater array at or just below the blanket surface evaporates deposited fountain solution and forms a fountain solution latent image on the surface. The heater array has controllable heating elements (e.g., field effect transistors, thin film transistors) that provide a transient heat pattern on the surface to evaporate the fountain solution. Heat is generated by current flow in the heating elements, and power developed by the heating circuit is the product of source-drain voltage and current in the channel. Current may be supplied along data lines by an external voltage controlled by digital electronics to provide the desired heat at heating elements addressed by a specific gate line. The heater array may include a current return line that may be a 2-dimensional mesh.

Abstract: Ink-based digital printing systems useful for ink printing include a rotatable charge-retentive reimageable surface layer configured to receive a layer of fountain solution. The fountain solution is carried to the charge retentive surface by a fog or mist including fountain solution aerosol particles, dispersed gas particles, and charge directors that impart charge to the fountain solution aerosol particles. The charge-retentive reimageable surface may be charged to a uniform potential, and selectively discharged using an ROS according to image data to form an electrostatic latent image. The charged fountain solution adheres to portions of the charge-retentive reimageable surface according to the electrostatic latent image to form a fountain solution image thereon. The fountain solution image can be partially transferred to an imaging blanket, where the fountain solution image is inked. The resulting ink image may be transferred to a print substrate.

Abstract: Ink-based digital printing systems useful for ink printing include a secondary roller having a rotatable reimageable surface layer configured to receive fountain solution. The fountain solution layer is patterned on the secondary roller and then partially transferred to an imaging blanket, where the fountain solution image is inked. The resulting ink image may be transferred to a print substrate. To achieve a very high-resolution (e.g., 1200-dpi, over 900-dpi) print with these secondary roller configurations, an equivalent very high-resolution fountain solution image needs to be transferred from the secondary roller onto the imaging blanket. To increase the resolution of the image on the secondary roller, examples include a textured surface layer added to the secondary roller for contact angle pinning the fountain solution on the roll. Approaches to introduce a micro-structure onto the surface layer of the secondary roller, and also superoleophobic surface coatings are described.