Abstract: A memristive device is disclosed herein. The device includes a first electrode, a second electrode, and an active region disposed between the first and second electrodes. At least two mobile species are present in the active region. Each of the at least two mobile species is configured to define a separate state variable of the memristive device.

Abstract: An optical apparatus includes an optical resonator ring having at least one active region. The active region is configured to generate optical energy under an electrical stimulus. The optical apparatus also includes a corrugated plasmonic body disposed around at least a portion of the resonator ring and radiatively coupled to the active region.

Abstract: A sensor fabric has a plurality of flakes of a flexoelectric material and electrodes as threads for connecting the flakes together. Each flake has at least one pair of opposite edges connected by two separate electrodes. When the sensor fabric is placed in contact with the surface of an object, the flake is bent along the contour of the object surface. The bending of the flexoelectric flake generates a polarization voltage between its opposite edges, which can be measured via the electrodes to determine the local surface contour of the object.

Abstract: Embodiments of the present invention are directed to nanowire (100) devices having concentric and coaxial doped regions and nanocrystals (108,110) disposed on the outer surfaces. In certain embodiments, the nanowire devices can include a light-emitting region (120) and be operated as a light-emitting diode (“LED”) (200), while in other embodiments, the nanowire devices can be operated as a light-detection device (600). The nanocrystals (108,110) disposed on the outer surfaces provide electron-conduction paths and include spaces that allow light to penetrate and be emitted from nanowire regions.

Abstract: A composite material with at least one of a negative effective permittivity and a negative effective permeability for incident radiation of at least one wavelength is described. The composite material comprises conductive structures that are substantially random with respect to at least one of size, shape, orientation, and location.

Abstract: An optical modulator and related methods are described. In accordance with one embodiment, the optical modulator comprises a waveguide for guiding an optical signal, and further comprises a ring resonator disposed in evanescent communication with the waveguide for at least one predetermined wavelength of the optical signal. The optical modulator further comprises a semiconductor pnpn junction structure that is at least partially coextensive with at least a portion of a resonant light path of the ring resonator. The optical modulator is configured such that the semiconductor pnpn junction structure receives an electrical control signal thereacross. The electrical control signal controls a free carrier population in the resonant light path where coextensive with the pnpn junction structure. A resonance condition of the ring resonator at the predetermined wavelength is thereby controlled by the electrical control signal, and the optical signal is thereby modulated according to the electrical control signal.

Abstract: An apparatus and related methods for facilitating surface-enhanced Raman spectroscopy (SERS) are described along with methods for fabricating the apparatus. For one embodiment, the apparatus comprises a metallic fishnet defining a plurality of voids therein. The metallic fishnet exhibits at least one acute V-shaped cross-sectional feature between at least one adjacent pair of the voids.

Abstract: An optical device includes at least two materials forming a structure with a graded bandgap where photocarriers are generated. A first of the at least two materials has a larger concentration at opposed ends of the graded bandgap structure than a concentration of the first of the at least two materials at an interior region of the graded bandgap structure. The second of the at least two materials has a larger concentration at the interior region of the graded bandgap structure than the concentration of the second of the at least two materials at the opposed ends of the graded bandgap structure.

Abstract: An optical apparatus includes an optical resonator ring having at least one active region. The active region is configured to generate optical energy under an electrical stimulus. The optical apparatus also includes a corrugated plasmonic body disposed around at least a portion of the resonator ring and radiatively coupled to the active region.

Abstract: A composite material and related methods are described, the composite material configured to exhibit at least one of a negative effective permittivity and a negative effective permeability for incident radiation of at least one wavelength. The composite material comprises an arrangement of electromagnetically reactive cells of small dimension relative to the wavelength, each cell having a plurality of quantum dots associated therewith for enhancing a resonant response thereof to the incident radiation at the wavelength.

Abstract: Embodiments of the present invention are directed to nanowire (100) devices having concentric and coaxial doped regions and nanocrystals (108, 110) disposed on the outer surfaces. In certain embodiments, the nanowire devices can include a light-emitting region (120) and be operated as a light-emitting diode (“LED”) (200), while in other embodiments, the nanowire devices can be operated as a light-detection device (600). The nanocrystals (108, 110) disposed on the outer surfaces provide electron-conduction paths and include spaces that allow light to penetrate and be emitted from nanowire regions.

Abstract: An apparatus for thermal control includes a first component; a second component; an adjustable thermal link disposed between the first component and the second component; and a controller for selectively varying a thermal conductance of the adjustable thermal link. A method of controlling a temperature includes sensing a temperature of a first component; and adjusting a thermal conductance of an adjustable thermal link, the adjustable thermal link forming a thermal path between the first component and a second component; the thermal conductance of the adjustable thermal link being adjusted such that the temperature of the first component is controlled.

Abstract: One embodiment of the present invention relates to a light-emitting diode having one or more light-emitting layers, a pair of electrodes disposed on the light-emitting diode so that an operating voltage can be applied to generate light from the one or more light-emitting layers, and at least one external electrode in electronic communication with the one or more light-emitting layers. Applying an appropriate voltage to the at least one external electrodes at about the time the operating voltage is terminated extracts excess electrons from the one or more light-emitting layers and reduces the duration of electron-hole recombination during the time period over which the operating voltage is turned off.

Abstract: A gain clamped optical device includes a semiconductor stack and a resonant cavity configured to emit stimulated light. A window created in the optical device is configured to emit the stimulated light in an LED mode.

Abstract: An apparatus has multiple sets of independently addressable interdigitated nanowires. Nanowires of a set are in electrical communication with other nanowires of the same set and are electrically isolated from nanowires of other sets.

Abstract: An optical resonator configured to be tuned using a charge-based memory cell includes an optical cavity configured to transmit light and receive injected charge carriers; a charge-based memory cell in proximity to or within the optical cavity, the memory cell containing a number of trapped charges which influence the resonant optical frequency of the optical resonator. A method of tuning an optical resonator includes applying a voltage or current to a charge-based memory cell to generate a non-volatile charge within the memory cell, the nonvolatile charge changing a resonant frequency of the optical resonator.

Abstract: An optical device includes at least two materials forming a structure with a graded bandgap where photocarriers are generated. A first of the at least two materials has a larger concentration at opposed ends of the graded bandgap structure than a concentration of the first of the at least two materials at an interior region of the graded bandgap structure. The second of the at least two materials has a larger concentration at the interior region of the graded bandgap structure than the concentration of the second of the at least two materials at the opposed ends of the graded bandgap structure.

Abstract: An optical resonator configured to be tuned using piezoelectric actuation, includes a core, the core being configured to transmit light; a piezoelectric layer; a first electrode and a second electrode. The piezoelectric layer is interposed between the first electrode and the second electrode. A voltage difference across the first and second electrodes alters a geometric dimension of the piezoelectric layer such that physical force is applied to the core and a resonant optical frequency of the resonator is changed. A method of utilizing mechanical stress to tune an optical resonator includes applying physical force to the resonator by subjecting a piezoelectric material to an electric field, the physical force changing a resonant frequency of the resonator.

Abstract: Modulation of electromagnetic radiation is described in which an incident radiation beam is directed toward a surface of a composite material and at least partially reflects to form a reflected radiation beam. The composite material comprises an arrangement of electromagnetically reactive cells of small dimension relative to a wavelength of the incident radiation beam, and exhibits at least one of a negative effective permeability and a negative effective permittivity for at least one frequency. A modulation signal is applied to the composite material to cause a variation in at least one of the effective permeability and the effective permittivity, at least one characteristic of the reflected radiation beam being modulated according to the modulation signal.

Abstract: Modulation of electromagnetic radiation is described in which an incident radiation beam is directed toward a surface of a composite material and at least partially reflects to form a reflected radiation beam. The composite material comprises an arrangement of electromagnetically reactive cells of small dimension relative to a wavelength of the incident radiation beam, and exhibits at least one of a negative effective permeability and a negative effective permittivity for at least one frequency. A modulation signal is applied to the composite material to cause a variation in at least one of the effective permeability and the effective permittivity, at least one characteristic of the reflected radiation beam being modulated according to the modulation signal.