Abstract: A laser communication system and method are disclosed. The laser communication system includes a laser receiver system to receive a frequency-shift keyed (FSK) optical signal encoded with a plurality of data signals. The laser receiver system including an FSK differential detection system that includes a plurality of differential detection filters that can each receive the FSK optical signal and generate an output. The FSK differential detection system can demodulate the FSK optical signal into a multi-bit digital code corresponding to a frequency of the FSK optical signal based on the output of each of the plurality of differential detection filters.

Abstract: According to an example, an apparatus for performing spectroscopy includes a perimeter wall extending between a first end and a second end of the perimeter wall along a first axis, in which an interior surface of the perimeter wall forms a hollow core extending along the first axis. The perimeter wall has openings at both the first end and the second end and light is to pass through the perimeter wall. The apparatus also includes a plurality of SES modules positioned around an inner circumference of the perimeter wall in a spaced arrangement with respect to each other to allow light to enter into the hollow core in gaps between the plurality of SES modules, in which each of the plurality of SES modules is positioned substantially across from a gap.

Abstract: A covert label structure comprising a three dimensional diffracting optical element layer (100) having a depth profile for producing a predetermined pattern, wherein different portions of a top surface of the diffracting optical element layer (100) have at least two different depths relative to a bottom surface of the diffracting optical element layer (100), wherein the depth profile spans across two dimensions of the top surface of the diffracting optical element layer (100), and wherein the top surface reflects light according to the predefined pattern and an overcoat layer (108) over the top surface of the diffracting optical element layer (100) wherein the overcoat layer (108) is opaque to at least one wavelength of light.

Abstract: A graphite-based sensor includes an undoped graphite structure that adsorbs foreign atoms and molecules. A magnetization detection device includes a substrate on which the graphite structure is adhered, a current source by which a current is applied to the substrate and the graphite structure, and a voltage measuring device coupled to the substrate. When the graphite structure adsorbs the gas molecules, the graphite structure exhibits a ferromagnetic-type behavior, and a corresponding voltage generated in the magnetic detection device changes.

Abstract: An apparatus for surface enhanced Raman spectroscopy includes a substrate, a nanostructure and a plasmonic material. The nanostructure and the plasmonic material are integrated together to provide electronic and plasmonic enhancement to a Raman signal produced by electromagnetic radiation scattering from an analyte.

Abstract: In an implementation, a Germanium on insulator apparatus is fabricated by forming a patterned masking layer on a Silicon on insulator (SOI) layer that leaves a portion of the SOI layer exposed, implanting Germanium onto the exposed portion of the SOI layer to form a Silicon-Germanium island, depositing amorphous Germanium over the Silicon-Germanium island and the patterned masking layer, removing the patterned masking layer and the amorphous Germanium that was deposited onto the patterned masking layer to produce a Silicon-Germanium composite stripe, and annealing the Silicon-Germanium composite stripe to crystallize the amorphous Germanium in the Silicon-Germanium composite stripe.

Abstract: A system includes an optical Y-junction coupler to receive a first modulated optical signal on a wide input path of the optical Y-junction coupler and to receive a second modulated optical signal on a narrow input path of the optical Y-junction coupler, wherein the optical Y-junction coupler generates a combined optical signal from signals received on the wide input path and the narrow input path. A multimode waveguide receives the combined optical signal from the optical Y-junction coupler and propagates a spatially multiplexed optical output signal along a transmission path.

Abstract: Examples of integrated sensors are disclosed herein. An example of an integrated sensor includes a flexible substrate, and an array of spaced apart sensing members formed on a surface of the flexible substrate. Each of the spaced apart sensing members includes a plurality of polygon assemblies. The polygon assemblies are arranged in a controlled pattern on the surface of the flexible substrate such that each of the plurality of polygon assemblies is a predetermined distance from each other of the plurality of polygon assemblies, and each of the plurality of polygon assemblies including collapsible signal amplifying structures controllably positioned in a predetermined geometric shape.

Abstract: A sensor for surface enhanced Raman spectroscopy (SERS) sensor includes surfaces and an actuator to adjust an intersurface spacing between the surfaces to contain an analyte and allow the analyte to be released from containment.

Abstract: A pattern recognition system includes an active media, an input system, and a sensing system. The active media is such that initial states respectively evolve over time to distinguishable final states. The input system establishes in the active media in an initial state corresponding to an input pattern, and the sensing system measures the media at separated locations to identify of which of the final states the media has after an evolution time. The identification of the final state indicates a feature of the input pattern.

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: A self-repairing memristor and methods of operating a memristor, and repairing a memristor, employ thermal annealing. The thermal annealing removes a short circuit in an oxide layer, of the memristor. Thermal annealing includes heating the memristor, to a predetermined annealing temperature for a predetermined annealing time period. The memristor, returns to an electrically open circuit condition after the short circuit is removed.

Abstract: A system for routing optical signals includes a waveguide array and a cylindrical resonator lying across the waveguide array, the cylindrical resonator having independently controllable tangential interfaces with each of the waveguides within the waveguide array. A method of selectively routing an optical signal between waveguides includes selecting a optical signal to route; determining the desired path the optical signal; tuning a first controllable interface between a cylindrical resonator and a source waveguide to extract the optical signal from the source waveguide; and tuning a second independently controllable interface between the cylindrical resonator and a destination waveguide to deposit the optical signal into the destination waveguide.

Abstract: A method for making a cross-linked polymer network is disclosed herein. A mixture is formed of i) an electro-optic chromophore, ii) any of a cross-linkable monomer or a cross-linkable oligomer, and iii) an initiator in a solvent. Poling of the electro-optic chromophore is initiated by exposing the mixture to an electric field. While the mixture is being exposed to the electric field, the mixture is subjected to ultraviolet light or heat to initiate cross-linking of the any of the cross-linkable monomer or the cross-linkable oligomer to form a matrix of the cross-linked polymer network.

Abstract: An apparatus for phase detection of Raman scattered light emitted from a sample includes a first polarizer positioned along a first optical path containing a first beam and a second polarizer positioned along a second optical path containing a second beam. The first polarizer and second polarizer polarize the first beam and the second beam in one of mutually perpendicular and mutually parallel first and second directions. The apparatus also includes an optical phase modulator positioned along the second optical path to controllably modulate a phase of the second beam, a beam splitter positioned to join the first beam and the second beam together, and a spectrometer to receive the joined first beam and second beam and to measure a phase shift of the first beam and the second beam.

Abstract: A memristive device includes a first electrode, a second electrode crossing the first electrode at a non-zero angle, and an active region disposed between the first and second electrodes. The active region has a controlled defect profile throughout its thickness.

Abstract: A field concentrating surface enhanced Raman spectroscopy (SERS) platform includes a signal amplifying material and a pattern of apertures extending through the signal amplifying material. The pattern of apertures includes a central aperture, and a plurality of radiation capturing apertures positioned around the central aperture. Each of the radiation capturing apertures has a diameter that is larger than a diameter of the central aperture. The platform further includes a substrate that supports the signal amplifying material and a channel that extends through the substrate. The channel is at least partially aligned with the central aperture that extends through the signal amplifying material.

Abstract: Apparatus, methods, and hollow metal waveguides to perform surface-enhanced Raman spectroscopy are disclosed. An example apparatus includes a hollow metal waveguide to direct Raman photons from an intermediate location within a volume of the hollow metal waveguide toward a distal end of the hollow metal waveguide, and a mirror to direct incident light from a light source to the intermediate location within the volume of the hollow metal waveguide and to direct at least some of the Raman photons toward the distal end.

Abstract: An electrically driven device for surface enhanced Raman spectroscopy includes a first electrode, a substrate positioned proximate to the first electrode, a plurality of cone shaped protrusions formed integrally with or on a substrate surface, a Raman signal-enhancing material coated on each protrusion, and a second electrode positioned relative to the first electrode at a predetermined distance. Each of the protrusions has a tip with a radius of curvature ranging from about 0.1 nm to about 100 nm. The second electrode is positioned relative to the first electrode such that the electrodes together produce an electric field when a voltage bias is applied therebetween. The electric field has a field distribution that creates a stronger field gradient at a region proximate to the tips than at other portions of the substrate.

Abstract: A dynamic optical crossbar array includes a first set of parallel transparent electrode lines, a bottom set of parallel electrode lines that cross said transparent electrode lines, and an optically variable material disposed between said first set of transparent electrode lines and said bottom set of electrode lines.