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This invention pertains to a hollow core photonic band gap chalcogenide optical glass fiber and to a fabrication method for making the fiber. The fiber, which is 80-1000 microns in outside diameter, is characterized by a solid glass circumferential region and a structured region disposed centrally within the solid region, the structured region includes a hollow core of 1 micron to several hundreds of microns in diameter surrounded by a plurality of parallel hollow capillaries extending parallel to the core, the core being centrally and longitudinally located within the fiber. Ratio of open space to glass in the structured region is 30-99%. The fabrication method includes the steps of providing a mold, placing chalcogenide micro-tubes around the mold, stacking chalcogenide micro-canes around the stacked micro-tubes, fusing the micro-tubes and the micro-canes to form a preform, removing the mold and drawing the preform to obtain the fiber. In an alternative fabrication method, the fiber is made by extruding flowing chalcogenide glass through suitably made plate to form a preform and then drawing the preform to form the fiber.
A two-photon absorption (TPA) switch is provided for minimizing which-path information in quantum optic interference. The TPA switch includes a pulse laser, first and second dichroic mirrors, a down-conversion crystal, a reflector, and a beam-splitter. The pulse laser emits a pump photon traveling along a photon-incident direction. The dichroic mirrors are disposed along the incident direction and oriented to enable photons to either pass there-through or perpendicularly reflect perpendicular to the incident direction. The down-conversion crystal is disposed between the dichroic mirrors along the incident direction and is non-critically phase-matched with signal and idler photons controlled by temperance of the crystal. The beam-splitter is disposed along one of the reflection directions to probabilistically reflect one of the signal and idler photons to pass through the crystal.
This invention pertains to a glass fiber, a Raman device and a method. The fiber is a hollow core photonic bandgap chalcogenide glass fiber that includes a hollow core for passing light therethrough, a Raman active gas disposed in said core, a microstructured region disposed around said core, and a solid region disposed around said microstructured region for providing structural integrity to said microstructured region. The device includes a coupler for introducing at least one light signal into a hollow core of a chalcogenide photonic bandgap fiber; a hollow core chalcogenide photonic bandgap glass fiber; a microstructured fiber region disposed around said core; a solid fiber region disposed around said microstructured region for providing structural integrity to said microstructured region; and a Raman active gas disposed in the hollow core. The method includes the steps of introducing a light beam into a hollow core chalcogenide photonic bandgap glass fiber filled with a Raman active gas disposed in the core, conveying the beam through the core while it interacts with the gas to form a Stokes beam of a typically higher wavelength, and removing the Stokes beam from the core of the fiber.
A high power ultrashort chirped pulse amplifier laser system, with a chirped pulse amplifier laser module including an optical pulse stretcher, at least one optical power amplifier, and an optical pulse compressor, and a beam interferometer module in the optical path. The beam interferometer receives splits the pulse into at least two pulses, adds a time delay to at least one of the pulses and recombines the pulses to produce a temporally modulated pulse. The resulting modulated output pulse from the CPA laser module can have enhanced laser contrast due to greatly reduced subpicosecond pedestal in the immediate region of the peak pulse, or can have other desirable characteristics.
A metafilm is provided for operating on a photon at a defined wavelength, for super-scattering, absorption, and for laser absorber switch. The metafilm includes dimers and a conductive substrate for embedding the dimers in an array. Each dimer comprises a pair of a gain element and a loss element. The substrate, and the gain and loss elements have complex permittivity values. The metafilm super-scatters (e.g., lases) the photon in response to increasing the imaginary component of either the substrate or the loss element, and absorbs the photon in response to increasing the imaginary component of the gain element.
Laser systems and related methods are provided. In this regard, a representative laser system includes: a laser diode array that generates light; a first crystal having a cavity; an optical element operative to focus the generated light onto the first crystal such that the light generates a high-power circulating beam within the cavity; a second crystal positioned with respect to the first crystal such that the frequency of the high-power circulating beam is doubled; and a first coating applied to the first crystal and second coating applied to the second crystal, the first coating and the second coating being operative to cause at least a portion of the beam to be emitted within a particular wavelength range of the generated light.
This invention pertains to a device for broadening optical wavelength in the 2–14 μm region comprising a light source and a highly nonlinear chalcogenide fiber associated therewith whereby a light signal is passed from the light source into the fiber wherein and through interactions between the light signal and the material, bandwidth of the light signal is broadened in the 2–14 μm region.
A waveguide device for frequency mixing or conversion through birefringent phase matching, having a horizontal waveguide suspended above a substrate. The waveguide is formed of a zinc blend type III-V semiconductor material with a high nonlinear susceptibility.
A photoconductive antenna is described that includes a substrate that includes a pair of trenches. Furthermore, a pair of non-parallel electrodes, which can be designed with a chaotic electrode geometry, can each be deposited in one of the trenches, and can be configured to produce chaotic trajectories of incoherent electric currents. Finally, an insulation layer, which can be either a physical electrical insulation layer or an air gap, can be included between each of the pair of non-parallel electrodes and the trench walls. Overall, the thickness of the substrate, the thickness of the trenches, and the thickness of the non-parallel electrodes can each be optimized to produce a coherent terahertz beam.
Optical devices that include one or more structures fabricated from polar-dielectric materials that exhibit surface phonon polaritons (SPhPs), where the SPhPs alter the optical properties of the structure. The optical properties lent to these structures by the SPhPs are altered by introducing charge carriers directly into the structures. The carriers can be introduced into these structures, and the carrier concentration thereby controlled, through optical pumping or the application of an appropriate electrical bias.
A dynamically variable lens is made from actively tunable electromagnetic metamaterial cells. The lens operates on electromagnetic radiation including: radio frequency waves, microwaves, teraherz waves, near infrared waves, infrared waves and visible waves. The focal length of the lens is changed at a selected frequency. In the alternative, the frequency of radiation operated on is changed as a function of time. A third alternative provides precise control of the index of refraction of the lens. The index of refraction is varied progressively across the lens from one edge to the opposite edge causing the radiation to be directed at an angle.
A multimode interference device and a method of configuring the same comprises a multimode interference region having a major axis; and a plurality of ports connected to a side portion of the multimode interference region, wherein the side portion is positioned in a direction other than perpendicular to the major axis.
Multilayered nanoparticles and methods of producing same are provided for controlling plasmon-exciton distance. The nanoparticles include a silver core, a polyelectrolyte spacer layer exterior to the silver core, and a J-aggregate cyanine dye outer shell. This multilayer architecture served as a framework for manipulating the dual coupling of localized surface plasmon resonance exhibited by the silver core with the molecular exciton exhibited by the J-aggregate outer shell. The polyelectrolyte spacer layer promotes the formation of an excitonic J-aggregate while serving as a means of controlling the plasmon-exciton coupling strength through changing the distance between the core and the shell. An analytical expression based on Mie Theory and the Transfer Matrix Method is provided for describing the optical response of these multilayered nanoparticles. Computational and experimental results illustrate that the absorption wavelength of the J-aggregate form of the dye is dependent on both the distance of the dye layer from the silver core and the degree of dye aggregation.
A preferred embodiment comprises a dynamic display based on a program image element which will only generate a preprogrammed image. As an example, the image element may comprise electrically-driven MEMS mirrors. This example may be embedded in an ID card. At the time of issue of the ID card, pixels in the mirror array will be permanently programmed as either ‘alive’ or ‘dead’ in a pattern matching the photo of the person in question. When stimulated, only ‘alive’ pixels will actuate, creating an image for comparison to the adjacent printed photo. Due to its dynamic behavior, delicate mechanical structures, and single-time hard-wiring, duplication of, or tampering with, this secondary dynamic image will be nearly impossible. The ID car is but one exemplary application and other embodiments, applications, and methods are described in the specification and claims.
Current channels, blocking areas, or strips in a semiconductor laser are used to channel injected current into the antinodal region of the optical standing wave present in the optical cavity, while restricting the current flow to the nodal regions. Previous devices injected current into both the nodal and antinodal regions of the wave, which is fed by the population inversion created in the active region by the injected electrons and holes, but inversion created in the nodal regions is lost to fluorescence or supports the creation of undesirable competing longitudinal modes, causing inefficiency. Directing current to the antinodal regions where the electric field is at its maximum causes a selected longitudinal mode to preferentially oscillate regardless of where the longitudinal mode lies with respect to the gain curve. In one embodiment, exacting fabrication of the Fabry-Perot cavity correlates the current channels to antinodal regions, vis-a vis current blocking areas, strips or segmented layers.
Various embodiments of an improved electro-optic shutter are disclosed. One embodiment comprises an electro-optic element, first and second polarizers, and a pair of electrodes. The electro-optic element has opposing transverse surfaces and operates as a half wave plate when a voltage Vπ is applied to the element. The first and second polarizers are each disposed adjacent to one transverse surface of the electro-optic element. The first and second electro-optic element have parallel transmission axes. Each electrode is disposed on one of the transverse surfaces of the electro-optic element and has an electric field which is substantially uniform over the transverse extent of the electro-optic element.
A method for emitting laser radiation includes: emitting first laser radiation using a first laser, wherein said first laser is a laser diode; receiving the first laser radiation by a second laser comprising CdSe(1-x)Sx (cadmium selenium sulfide, cadmium selenium, or cadmium sulfide), wherein x is between 0 and 1, inclusively; and responsive to receiving the first laser radiation by the second laser, emitting second laser radiation by the second laser via the CdSe(1-x)Sx; wherein the second laser radiation has a wavelength between 487 nm and 690 nm; and wherein the wavelength of the second laser radiation is responsive to the value of x, which represents the relative concentration of selenium and/or sulfur.
The invention includes a deformable mirror for use in adaptive and active optical systems and in optical technology laser communication directed energy systems. The invention utilizes pockets formed in the back of the mirrors substrate. The pockets house actuators that are bonded to the substrate and may adjustably deform the mirror surface depending on the voltage supplied to the actuators. A plurality of mirrors may be combined to form a scalable array or positioned to overcome issues related to the uncontrollable portions of separate individual mirrors.
A large-aperture direct-view high-speed electro-optic shutter includes an electro-optic polymer material constructed to form a Pockels cell and an integrated photoconducting semiconductor switch. A chromophore-doped polymer material or chromophore copolymer, wherein the chromophore is oriented within the polymer material, exhibits a linear electro-optic effect when an electric field is applied to the device. In one embodiment, the polymer host material comprises one or more of a polycarbonate, amorphous polycarbonate, or polymethylmethacrylate polymer hosts. The optically active chromophore comprising one or more coumarin and coumarin derivatives, stilbene or tolane derivatives is incorporated within the polymer host, forming a guest-host polymer. In another embodiment, the chromophore is chemically bonded to the monomer that forms the polymer, resulting in an optically active copolymer. The electro-optic shutter device is then activated by incident light through the photoconducting semiconductor switch, rendering the Pockels cell to have an optical density of at least 3.0.
A method for displaying information via a light source on rotating helicopter blades of an aircraft such as a helicopter is provided. The light source may be a laser light source and the light therefrom may be directed onto the aircraft blade by one or more motion controlled mirrors and a computer controller. A sensor is capable of determining the position of helicopter blades during rotation, such that light may be projected upon only the moving blade at precisely timed intervals, so as to form perceivable graphics and/or messages thereon. In addition, the method may be utilized for displaying graphics and/or messages on rotating propellers of fixed wing aircraft.
A method for forming a device having nanopillar and cap structures on a substrate in which the substrate is first coated with a first resist having a first exposure dose to electron beam radiation, and that after coating the first resist with a second resist having a second exposure dose less than the first resist. Electron beam lithography is then used sequentially to form the nanopillars and cap structures or, alternatively, a template for the nanopillar and cap structures.
A method and device for generating terahertz radiation comprising a polar crystal material layer operative to emit terahertz radiation; the polar crystal material layer comprising a plurality of stacking faults; the stacking faults lying substantially perpendicular to the polar axis and forming boundaries at which the internal electric polarization terminates leading to charges accumulating at the boundaries, and creation of internal electric fields oriented along the polar axis; a pulsed radiation source for creating photogenerated carriers in the polar crystal material; whereby the photogenerated carriers accelerate in the internal electric fields associated with the termination of the internal electric polarization by the stacking faults to thereby generate terahertz radiation.
Disclosed are a semiconductor device and method of manufacturing the same comprising a substrate, a mesa region adjacent to the substrate, an electroplated metal layer, for reducing the thermal resistance of the device, surrounding the mesa region, an insulator layer separating a side portion of the mesa region from the electroplated metal layer, a heat sink, a bonding layer adjacent to the heat sink, and a second metal layer in between the substrate and the heat sink, wherein the substrate is adjacent to the bonding layer, and wherein the electroplated metal layer dimensioned and configured to have a thickness of at least half a thickness of the mesa region; and to laterally spread heat away from the mesa region. The mesa region comprises a first cladding layer adjacent to the substrate, an active region adjacent the first cladding layer, and a second cladding layer adjacent to the active region.
A method and apparatus for controlled displacement, rotation and deformation of parts of a fiber optic collimator so as to provide multiple degrees of adjustment freedom that are decoupled one from another, for adjusting the path of a light beam, comprising: an output elongate hollow node for passing a light beam therethrough and towards a lens, and an elongate hollow base node having separate top and bottom parts connected to each other by opposed ends of a plurality of flexible rods that restrict the relative movement between the top and bottom parts of the base node to substantially only translational parallel movement. Opposed portions of the top and bottom parts of the base node each include a respective screw and an opposed slanted surface, which upon interaction, develop a shearing force which is applied to the top and bottom parts of the base node and cause a translational parallel relative movement therebetween.
A portable acousto-optical (AO) spectrometer system comprised of at least one AO crystal cell device specially designed for cancellation of side-lobe noise at a desired tuned wavelength of operation. Each AO crystal cell device has a transducer attached and forms an AO tunable filter (AOTF) and forms part of a photo-head assembly. The system can include an optical fiber link between the AO spectrometer photo-head assembly and additional features such as an optical alignment coupling attachment that couple an excitation source such as a laser that operates in either pulse or continuous mode, a probing fiber that provides a hand-held member that can emit a source radiation and in turn observe radiation reflected from an observed sample. There are two embodiment of the AO crystal cell device. Either embodiment of the AO crystal cell design can be used in the system, providing a vibration-insensitive AO spectrometer instrument having high sensitivity, accuracy and resolution capabilities. The types of spectroscopic measurements that can be performed using the invention include fluorescence, Raman, absorption and emission.
An optical beamsplitter comprises an optically-transparent material and a partially-reflective layer therein. The optically-transparent material has a cylindrically shaped exterior surface which provides advantages.
A system for obtaining spectral images from polarized light comprising a polarization sensitive filter; the polarization sensitive filter being configured to receive light at at least one predetermined polarization orientation; and an achromatic waveplate operatively associated with the polarization sensitive filter; the achromatic waveplate being rotatable; whereby rotation of the achromatic waveplate enables light to enter the polarization sensitive spectral filter at at least two predetermined polarization orientations. A method comprising providing a polarization sensitive filter; the polarization sensitive filter being configured to receive light at at least one predetermined polarization orientation; providing an achromatic waveplate operatively associated with the polarization sensitive filter; the achromatic waveplate being rotatable; whereby rotation of the achromatic waveplate enables light to enter the polarization sensitive spectral filter at the at least two predetermined polarization orientations.
A rotatable optical beamsplitter comprises an optically-transparent material and a partially-reflective layer. The optically-transparent material has a unitary spherical exterior surface. The partially-reflective layer is located at least partially within the optically transparent material. The spherically shaped optical beamsplitter demonstrates reduced optical distortion.
A composition is provided that includes a polymer matrix. A core having a core surface is embedded within the polymer matrix. A polymeric ligand passivates the core surface and has a moiety Y, where Y is a Diels-Alder group of a diene or dienophile. A polymeric linker has a complementary Diels-Alder group diene or dienophile to moiety Y and forms a Diels-Alder bond with the moiety Y. A composition is also provided that includes polymer matrix having a matrix surface. A core having a core surface is present on the matrix surface. A polymeric ligand passivates the core surface and has a moiety Y, where Y is Diels-Alder group of a diene or dienophile. The polymer matrix and polymeric ligand together define a matrix-ligand Flory-Huggins binary interaction function greater than 0.
A system for displaying information via a light source on rotating helicopter blades of an aircraft such as a helicopter is provided. The light source may be a laser light source and the light therefrom may be directed onto the aircraft blade by one or more motion controlled mirrors and a computer controller. A sensor is capable of determining the position of helicopter blades during rotation, such that light may be projected upon only the moving blade at precisely timed intervals, so as to form perceivable graphics and/or messages thereon. In addition, such system may be utilized for displaying graphics and/or messages on rotating propellers of fixed wing aircraft.
A method and device for generating terahertz radiation comprising a plurality of layers of polar crystal material operative to emit terahertz radiation; the plurality of layers comprising transport layers and divider layers, the plane of the layers being not parallel to the polar axis, the interface between the transport layers and divider layers forming boundaries at which the internal electric polarization terminates leading to charges accumulating at the boundaries, and creation of internal electric fields oriented along the polar axis.
A method and device for generating terahertz radiation comprising a substrate; a plurality of segments of polar crystal material formed on the substrate, the segments having an internal electric polarization; each segment comprising at least two edges oriented substantially perpendicular to the polar axis such that the electric polarization terminates at the edges and the segment comprises a majority of positive charges on one edge and a majority of negative charges on the opposite edge thereby leading to creation of an internal electric field; whereby when irradiated by a pulsed source of duration less than one picosecond, electron-hole pairs are generated within the segments and the internal electric field separates and accelerates the electron-hole pairs to thereby produce terahertz radiation.
A device for the positioning of fiber optic output including a base having a hole disposed at a midpoint thereof, a collar having an opening at a midpoint, a plurality of bimorph actuators, each actuator connected to an outer side surface of the base and located at opposite ends, a plurality of flexible beams, each having a first end connected to the collar and a second end connected to a bimorph actuator, a flexible tube inserted in the hole, where a bottom end of the tube is cantilevered at a bottom of the base and a top end of the tube is inserted in the opening of the collar, and a fiber optic embedded in the flexible tube.
A composite laser gain medium is comprised of a first rare-earth element doped core; and a second rare-earth element doped cladding, at least partially, adjacent to the core. A portion of the lasing by the cladding at one wavelength within the composite laser gain medium is absorbed by the core so as to cause lasing of the core at a different wavelength. At least two distinct rare earth element pairs may be used in embodiments: (1) thulium (Tm) as a cladding rare-earth dopant and holmium (Ho) as the core rare-earth dopant; and (2) ytterbium (Yb) as a cladding rare-earth dopant and erbium (Er) as the core rare-earth dopant. Other rare earth element pairs are also believed possible. The laser composite gain medium may be configured to have a slab, or a cylindrical geometry.
A method and apparatus for coherent beam combining in an array of laser beam collimators. The array of laser beam collimators includes an array of a plurality collimating lenses, each lens intercepting a respective one of a plurality of divergent laser beams. Each collimating lens is joined with adjacent collimating lenses such that an output aperture is formed with a common vertex of the adjacently joined collimating lenses. A concave mirror is positioned a distance from the common vertex for receiving a fraction of each of the collimated laser beams that passed through a portion of each of the collimating lenses that are adjacent to the common vertex, and then providing reflected fractional collimated laser beams. A sensor intercepts the reflected fractional collimated laser beams so as to provide a signal that is applied to synchronize the phase of each of the collimated laser beams.
The subassembly includes a laser for emitting signals towards fibers to be monitored, a passive alignment carrier, a photodetector for monitoring reflected laser signals from the fibers and for monitoring laser output power, and an optical fiber. The laser is disposed within the passive alignment carrier. The optical fiber is embedded in the passive alignment carrier, and has an angled fiber facet. The laser emits signals toward and through the angled fiber facet, whereby a portion of the laser signal illuminates the photodetector, and another portion illuminates the fibers that are being monitored and reflects back to the photodetector such that faults on the fibers can be detected.
An electro-optic device with a doped semiconductor base and a plurality of pixels on the semiconductor base, each pixel including: a multiple quantum well formed on the semiconductor base, an oppositely doped semiconductor layer on the multiple quantum well, and a top electrode on the semiconductor layer, the top electrode shaped to produce an approximately uniform lateral resistance in the pixel. An embodiment is a large area modulator for modulating retro-reflector systems, which typically use large area surface-normal modulators with large lateral current flow. Uniform resistance to each part of the modulator decreases location dependence of frequency response. A chirped grid electrode balances semiconductor sheet resistance and metal line resistance components of the series resistance.
A wavelength converter comprising an arsenic sulfide (As—S) chalcogenide glass fiber coupled to an optical parametric oscillator (OPO) crystal and a laser system using an OPO crystal coupled to an As—S fiber are provided. The OPO receives pump laser radiation from a pump laser and emits laser radiation at a wavelength that is longer than the pump laser radiation. The laser radiation that is emitted from the OPO is input into the As—S fiber, which in turn converts the input wavelength from the OPO to a desired wavelength, for example, a wavelength beyond about 4.4 μm. In an exemplary embodiment, the OPO comprises a periodically poled lithium niobate (PPLN) crystal. The As—S fiber can include any suitable type of optical fiber, such as a conventional core clad fiber, a photonic crystal fiber, or a microstructured fiber.
An electro-optic device with a doped semiconductor base and a plurality of pixels on the semiconductor base. Pixels include oppositely doped semiconductor layer and a top electrode formed on the oppositely doped semiconductor layer. The top electrode has a grid pattern with at least one busbar and a plurality of fingers extending from the busbar, and spacing between the fingers decreases with distance from the bondpad along the busbar. Each pixel can also include a multiple quantum well formed on the semiconductor base. The top electrode shape produces an approximately uniform lateral resistance in the pixel. An embodiment is a large area modulator for modulating retro-reflector systems, which typically use large area surface-normal modulators with large lateral current flow. Uniform resistance to each part of the modulator decreases location dependence of frequency response. A chirped grid electrode balances semiconductor sheet resistance and metal line resistance components of the series resistance.
A method of: directing an exposing light through an optical diffuser; directing the diffused light though a photomask having transparent areas corresponding to a gray-tone pattern; directing the masked light onto a photoresist material on a substrate; developing the photoresist to produce a three dimensional structure in the photoresist.
A modulating retroreflector system includes a modulating retroreflector having a plurality of multiple quantum well modulator pixels and at least one transimpedance amplifier. The transimpedance amplifier receives a photocurrent generated by at least one of the plurality of modulator pixels. Each pixel is capacitively coupled to a current driver, which applies a high frequency digital electrical signal to the pixel when the voltage at the output of the transimpedance amplifier exceeds a threshold value. The modulated output of the retroreflector is reflected toward the source of the received optical beam. The system activates high frequency current drivers for only the illuminated pixels, eliminating the need for a separate angle of incidence sensor and reducing power requirements. A low frequency FSK signal can be superimposed on the DC optical interrogation beam and recovered as the unfiltered output of the transimpedance amplifier, to provide simultaneous bidirectional communication without a half-duplex communication protocol.
This invention pertains to a holey fiber and to a fabrication method for making the fiber. The holey fiber can transmit light by total internal reflection or by Bragg diffraction, can be single mode or multimode and can have solid core or a hollow core. The holey fiber has outside diameter typically of 20 microns to 5 mm, a hollow core of a diameter typically of 0.2 micron to 150 microns and longitudinal channels therethrough of a diameter typically of 0.1 micron to 150 microns. The channels are disposed in a desired arrangement with center-to-center distance variation of less than about 2% along the length of the fiber and the cross-section thereof is round that varies less than about 2%.
Laser devices are presented in which a graphene saturable absorber and an optical amplifier are disposed in a resonant optical cavity with an optical or electrical pump providing energy to the optical amplifier.
Methods for improving the performance of type-II and type-I ICLs, particularly in the mid-IR wavelength range, are provided. The electron injector of a type-II or a type-I ICL can be heavily n-doped to increase the ratio of electrons to holes in the active quantum wells, thereby increasing the probability of radiative recombination in the active quantum wells and reducing the threshold current density Jth needed to achieve lasing. For both type-II and type-I ICLs, the doping should have a sheet density in the low-1012 range. In either the type-II or the type-I case, in some embodiments, heavy doping can be concentrated in the middle quantum wells of the electron injector, while in other embodiments, doping with silicon can be shifted towards the active quantum wells.
Fiber optic amplification in a spectrum of infrared electromagnetic radiation is achieved by creating a chalcogenide photonic crystal fiber (PCF) structure having a radially varying pitch. A chalcogenide PCF system can be tuned during fabrication of the chalcogenide PCF structure, by controlling, the size of the core, the size of the cladding, and the hole size to pitch ratio of the chalcogenide PCF structure and tuned during exercising of the chalcogenide PCF system with pump laser and signal waves, by changing the wavelength of either the pump laser wave or the signal wave, maximization of nonlinear conversion of the chalcogenide PCF, efficient parametric conversion with low peak power pulses of continuous wave laser sources, and minimization of power penalties and minimization of the need for amplification and regeneration of pulse transmissions over the length of the fiber, based on a dispersion factor.
A planar or cylindrical, cantilever-type apparatus including a rigid support. The apparatus further includes a first optical fiber connected to the rigid support, the first optical fiber including a first neutral axis and at least one first wave-guiding core running parallel to the first neutral axis and located at a distance from the first neutral axis, each of the at least one first wave-guiding core including at least one first reflector. The apparatus further includes a first membrane surrounding the first optical fiber; and a first liquid inside the first membrane and surrounding the first optical fiber, the first liquid including a Reynolds number less than one.
An optical fiber comprising non-silica, specialty glass that has multiple fiber cores arranged in a square registered array. The fiber cores are “registered” meaning that the array location of any fiber core is constant throughout the entire length of the fiber, including both ends. Optical fiber bundles are fabricated by combining multiple multi-core IR fibers with square-registration. Also disclosed is the related method for making the optical fiber.
A method for isolating microstructural regions or features on a surface for electrochemical experimentation comprising polishing a metal sample, coating the metal sample with a photoresist, selecting a region of interest of the metal sample, exposing the region of interest with light energy, developing the exposed photoresist and creating a developed region.
A method for shaping an output light beam from an optical fiber by controlling the phase and amplitude of the beam by producing beam shaping elements on an exit facet of the optical fiber by direct surface texturing of the exit facet, where a controlled phase difference is achieved across the fiber cross-section over a predefined pattern. The optical fiber can be a single mode fiber or a multi-mode fiber. Either a binary or a complex phase difference can be achieved. Also disclosed is the related system for shaping an output light beam from an optical fiber.
An aromatic ether oligomer or polyaromatic ether comprising the formula: wherein Ar is an independently selected divalent aromatic radical; formed by reacting a dihydroxyaromatic with a dihaloaromatic; and wherein the reaction is performed in the presence of a copper compound and cesium carbonate. The polyaromatic ether is formed when neither the dihydroxyaromatic nor the dihaloaromatic is present in an excess amount. The aromatic ether oligomer is formed by using an excess of either dihydroxyaromatic or dihaloaromatic. A phthalonitrile monomer comprising the formula: formed by reacting a 3- or 4-nitrophthalonitrile with a hydroxy-terminated aromatic ether oligomer. A thermoset formed by curing the phthalonitrile monomer. Processes for forming all the above.
A photonic band gap fiber and method of making thereof is provided. The fiber is made of a non-silica-based glass and has a longitudinal central opening, a microstructured region having a plurality of longitudinal surrounding openings, and a jacket. The air fill fraction of the microstructured region is at least about 40%. The fiber may be made by drawing a preform into a fiber, while applying gas pressure to the microstructured region. The air fill fraction of the microstructured region is changed during the drawing.
An aromatic ether oligomer or polyaromatic ether comprising the formula: O—Arn; wherein Ar is an independently selected divalent aromatic radical; formed by reacting a dihydroxyaromatic with a dihaloaromatic; and wherein the reaction is performed in the presence of a copper compound and cesium carbonate. The polyaromatic ether is formed when neither the dihydroxyaromatic nor the dihaloaromatic is present in an excess amount. The aromatic ether oligomer is formed by using an excess of either dihydroxyaromatic or dihaloaromatic. A phthalonitrile monomer comprising the formula: formed by reacting a 3- or 4-nitrophthalonitrile with a hydroxy-terminated aromatic ether oligomer. A thermoset formed by curing the phthalonitrile monomer. Processes for forming all the above.
The present invention describes an apparatus for nanolithography and a process for thermally controlling the deposition of a solid organic “ink” from the tip of an atomic force microscope to a substrate. The invention may be used to turn deposition of the ink to the substrate on or off by either raising its temperature above or lowing its temperature below the ink's melting temperature. This process may be useful as it allows ink deposition to be turned on and off and the deposition rate to change without the tip breaking contact with the substrate. The same tip can then be used for imaging purposes without fear of contamination. This invention can allow ink to be deposited in a vacuum enclosure, and can also allow for greater spatial resolution as the inks used have lower surface mobilities once cooled than those used in other nanolithography methods.
Materials and structures whose index of refraction can be tuned over a broad range of negative and positive values by applying above band-gap photons to a structure with a strip line element, a split ring resonator element, and a substrate, at least one of which is a photoconductive semiconductor material. Methods for switching between positive and negative values of n include applying above band-gap photons to different numbers of elements. In another embodiment, a structure includes a photoconductive semiconductor wafer, the wafer operable to receive above band-gap photons at an excitation frequency in an excitation pattern on a surface of the wafer, the excitation patterns generating an effective negative index of refraction. Methods for switching between positive and negative values of n include projecting different numbers of elements on the wafer. The resonant frequency of the structure is tuned by changing the size of the split ring resonator excitation patterns.
A fiber optic sensor for detecting acceleration or displacement includes a fiber optic probe with a multimode transmitting optical fiber, a multimode receiving optical fiber and a edge reflector spaced apart from the fiber probe. The reflector moves in a transverse direction substantially normal to the longitudinal axis of the fiber optic probe, so the amount of light received by the receiving fiber indicates a relative acceleration or a relative displacement of the reflective surface with respect to the fiber probe in the transverse direction of motion of the edge of the reflector. The reflector can be mounted on a cantilever beam. The sensor can have one transmitting fiber, two receiving fiber, and a reflector with two edges, each edge partially covering one of the receiving fibers. A triaxial sensor system has at least two two-fiber sensors.
A synchronized delay-coupled laser system includes at least two lasers. Each laser includes a laser fiber with a coupling means for coupling to a laser pump. The lasers are coupled to each other by way of two optical fibers. Each laser also includes a self-feedback section. The optical fibers interconnecting the lasers and the self-feedback sections are configured to provide a substantially identical delay time. The lasers may be ring lasers, may be semi-conductor or solid state, and may include components such as a fiber amplifier, a polarization controller, and a nonlinear oscillator. The system includes multiple interconnected lasers and also employ cross-coupling connections.
Beam steering apparatus is presented having a Risley double-prism pair with first and second double-prisms disposed along an optical path, where one or more of the prisms are made from a chalcogenide glass material.
A method of flattening a deformable mirror (DM) such as a piezoelectric DM to correct for distortion includes inputting an incident light beam into a reference beam optical path while blocking the DM response, recording a flat wavefront (Φn, R) as a reference wavefront from a reference mirror, blocking the reference beam to obtain a DM response, activating a close-loop mode of DM Control Software and computing iterations until a difference between the reference wavefront and the DM response is minimized, recording a wavefront created by the DM (Φn, DM) and the corresponding voltage vector (Vn) applied to the DM; and applying a voltage vector to the DM to thereby flatten the DM and correct for the distortion. The method is useful in an application such as for ground-to-space links at Short Wave Infrared (SWIR) wavelengths.
An optical scanning system includes a frame having a central axis along which is mounted a first elevation mirror for receiving an incident light and reflecting the incident light along a first optical path, a telescope for receiving the reflected incident light and outputting an output light, a visible linear array imager for receiving the output light from the telescope, and a folding mirror positioned to receive part of the output light from the telescope and directing it to a linear array infrared imager. The optical scanning system scans large areas of sky using multiple linear sensors in order to detect, identify and track low and slow flying manned and unmanned aircraft as well as to surveil large areas of terrain.
A method for patterned deposition of an arbitrary thin film on an arbitrary substrate. A GaAs substrate having a bi-layer structure deposited thereon, the bi-layer structure consisting of a bottom layer of Ge and a top layer of SiN. A photoresist deposited on the top SiN surface of the sample is patterned to form one or more desired patterned features on the sample. The Ge—SiN bi-layer structure on the patterned sample is aniostropically etched so that an undercut is formed in the Ge layer, the SiN forming an overhang over a portion of the GaAs substrate. The remaining photoresist is removed from the sample and the film is deposited on the sample to form a feature on the substrate. The remaining Ge layer is etched away and the SiN layer and film deposited on the SiN layer are lifted from the sample, leaving only the patterned features on the substrate.
A laser apparatus uses a dysprosium doped chalcogenide glass fiber. The glass fiber has a laser pump operatively connected to it. The chalcogenide glass fiber is located in a laser cavity including one or more reflective elements such as a Bragg grating, a Bragg minor, a grating, and a non-doped fiber end face. The apparatus provides laser light output at a wavelength of about 4.3 μm to about 5.0 μm at a useful power level using laser light input at a wavelength of from about 1.7 μm to about 1.8 μm. Also disclosed is a method for providing laser light output at a wavelength of about 4.3 μm to about 5.0 μm using the apparatus of the invention.
This invention pertains to an optical device and method for using a chalcogenide glass waveguide to amplify a pump light beam by means of stimulated Raman scattering and obtaining a depleted pump light beam and an amplified beam at a wavelength higher than the wavelength of the depleted pump light beam.
This invention pertains to fiber termination combination which includes an optical fiber having a fiber core for transmitting a highly energetic optical signal that can damage the fiber and a structured region around the core for directing the optical signal into the core, the structured region being characterized by multiple channels of smaller internal diameter than the core defined by thin walls disposed around said core; a ferrule, with an opening therein for locating said fiber, at the end of said fiber enveloping said fiber extremity which cooperates with said blocking structure to block the optical signal from impinging on said microstructured region of said fiber; and a blocking structure disposed over the end of said fiber with an opening mating with said fiber core, said blocking structure blocking the optical signal from impinging on said microstructured region of said fiber.
A hollow core photonic bandgap chalcogenide glass fiber includes a hollow core for passing light therethrough, a Raman active gas disposed in said core, a microstructured region disposed around said core, and a solid region disposed around said microstructured region for providing structural integrity to said microstructured region. A coupler can introduce at least one light signal into the hollow core of the chalcogenide photonic bandgap fiber. The method includes the steps of introducing a light beam into a hollow core chalcogenide photonic bandgap glass fiber filled with a Raman active gas disposed in the core, conveying the beam through the core while it interacts with the gas to form a Stokes beam of a typically higher wavelength, and removing the Stokes beam from the core of the fiber.
An infrared laser source system that combines laser emitters through an optical waveguide. Each emitter is coupled to a port of the optical waveguide and the waveguided signal is combined to provide a spatially combined laser source with a single common exit aperture. The materials used for waveguiding allow the propagation of wavelengths in the infrared. The system can be used for combining multiple laser emitters to increase the total output power and/or for combination of multiple emitters with different wavelength for increased spectral coverage out of the laser system.
A composite having a stack of a repeating pattern of layers of: a layer of a nonconductive magnetic material, a first layer of a dielectric material; a layer of a semiconducting material; and a second layer of the dielectric material. The composite has a magnetic resonance frequency and a magnetic anti-resonance frequency and a plasma frequency at higher frequencies than the magnetic resonance frequency.
A lens system with a lens formed of a material having a negative index of refraction in an operational frequency range, a first surface of the material having a convex hyperbolic curvature, and a second surface of the material having a concave circular curvature. A lens system can include two of these lenses, arranged with the concave circular surfaces facing each other. Far field radiation arriving at the hyperbolic surface of the the first lens is refracted by the lens material toward the circular surface, out of the first lens in a direction parallel to the original radiation direction, and into the circular surface of the second lens, where it is refracted toward the hyperbolic surface of the second lens, and exits the second lens in a direction parallel to the original direction. The lens material can have a tunable or fixed negative refractive index and/or resonant frequency.
An embodiment of the invention includes an apparatus. The apparatus includes a plurality of lasers comprising a plurality of laser paths. The apparatus further includes an incoherent combining beam director in the plurality of laser paths. The apparatus also includes a plurality of optical elements in the plurality of laser paths between the plurality of lasers and the beam director.
A system and methods for the quasi-remote compression and focusing of a moderate-intensity laser pulse to form a much higher intensity beam that can be directed at a target and used as a probe beam or used in a probe beam converter to generate other forms of electromagnetic radiation or energetic particles. A system for the quasi-remote propagation of high-intensity laser beams in accordance with the present invention comprises a main platform on which a first, “seed” laser pulse is generated, stretched, and amplified, and a remote platform, located at a distance from the main platform, which is configured to receive the amplified and stretched pulse and convert it into the high-intensity laser beam. The high-intensity laser beam in turn can then be converted into one or more probe beams directed at a target object.
A multi-mode optoelectronic oscillator (MM-OEO) includes an OEO cavity having an input for receiving an RF signal and an RF output. The OEO cavity includes a) a first laser having a first laser output, a second laser having a second laser output, b) a modulator having i) a first input coupled to the first laser output, ii) a second input coupled to the second laser output, iii) a third input, iv) a first modulator output, and v) a second modulator output, c) a semiconductor optical amplifier (SOA) having an input coupled to the first modulator output and having an SOA amplified output, d) a photodetector coupled to the SOA amplified output and having an output, and e) a coupler having an input coupled to the photodetector output and having a first output coupled to the third modulator input and a second output, whereby an amplified RF signal is produced at the OEO RF output.
A waveguide device for frequency mixing or conversion through birefringent phase matching, having two suspended horizontal waveguides with an air-filled horizontal nanoslot between them. The waveguides are formed of a material with a high nonlinear susceptibility, and one waveguide can be n-doped with the other waveguide slab being p-doped. The system can be tuned to operate at different frequencies by varying the nanoslot gap distance by electrostatically actuating the suspended air-clad waveguides.
A heterojunction between thin films of NCD and 4H—SiC was developed. Undoped and B-doped NCDs were deposited on both n− and p− SiC epilayers. I-V measurements on p+ NCD/n− SiC indicated Schottky rectifying behavior with a turn-on voltage of around 0.2 V. The current increased over eight orders of magnitude with an ideality factor of 1.17 at 30° C. Ideal energy-band diagrams suggested a possible conduction mechanism for electron transport from the SiC conduction band to either the valence band or acceptor level of the NCD film.
A method of making an achromatic gradient index singlet lens comprising utilizing a gradient index material with a curved front surface in which light does not follow a straight line as it travels through the material and wherein different color rays traverse different curved paths, utilizing the natural dispersion of the curved front surface as a strong positive lens, and developing a weakly diverging GRIN distribution within the lens to balance the chromatic aberrations of the curved front surface.
An N port fiber optical switch includes a movable housing having a perimeter and N corners; a plurality N of optical fibers positioned within the housing and inside the perimeter; and a plurality N of actuators, wherein each actuator is positioned on a corresponding corner such that when selectively activated one or more of the actuators urges the movable housing and the plurality of optical fibers to a selected switch position. The switch provides short switching times and high power handling while allowing for a large number of ports and provides the capability of interfacing with and switching between a variable number of ports.
Methods for producing a laser-guided underwater electrical discharge are provided. One or more electrodes defining a desired electrical discharge path are situated in a body of water and are attached to an external electrical power supply. A high-powered, intense laser beam is fired into the water. The laser beam forms an optical filament in the water, which in turn forms an ionized channel having a much greater conductivity than the surrounding water. An external power supply drives an electrical discharge along the path of the ionized channel due to its greater conductivity.
A method for generating an extended underwater plasma. A first laser pulse is fired into a body of water to form an underwater optical filament coinciding with a low-energy plasma. A second laser pulse is fired into the water, targeted at the plasma. The second pulse heats the plasma, causing the formation of an extended superheated plasma volume in the water. The two laser pulses can be simultaneous or can be sequential, with the second pulse following the first pulse by up to the filament plasma lifetime. The extended superheated plasma creates an underwater acoustic pulse, wherein the duration, waveform and directivity of the pulse can be tailored by controlling the shape of the underwater laser-generated plasma.
The present invention is generally directed to a photonic bad gap fiber and/or fiber preform with a central structured region comprising a first non-silica based glass and a jacket comprising a second non-silica based glass surrounding the central structured region, where the Littleton softening temperature of the second glass is at least one but no more than ten degrees Celsius lower than the Littleton softening temperature of the first glass, or where the base ten logarithm of the glass viscosity in poise of the second glass is at least 0.01 but no more than 2 lower than the base ten logarithm of the glass viscosity in poise of the first glass at a fiber draw temperature. Also disclosed is a method of making a photonic bad gap fiber and/or fiber preform.
A method of generating a supercontinuum in chalcogenide fiber with a pump light comprising a short pulse fiber laser or diode laser operating with a wavelength of 1.0 μm or greater that is wavelength shifted through a nonlinear fiber one or more times and amplified one or more times and launched into a chalcogenide fiber whereby the spectrum is broadened in the chalcogenide fiber through various nonlinear processes to generate a supercontinuum within the mid-IR from 1.5 to greater than 5 μm.
A light-emitting device having one or more diamond layers integrated therein and methods for forming a light-emitting device with integrated diamond layers. The diamond is grown either directly on the semiconductor material comprising the light-emitting structure, on a nucleation layer deposited on the semiconductor material, or on a dielectric layer deposited on the semiconductor material before growth of the diamond layer. The device can include a trench or thermal shunt formed in the substrate on the backside of the device, or can include a heat sink to provide additional thermal management.
A true time delay system for optical signals includes a hollow core optical waveguide, a droplet of reflective liquid metal disposed in the hollow core, and an actuator coupled to a first end of the waveguide to move the droplet longitudinally within the hollow core. In one example, the waveguide is a hollow core photonic bandgap fiber. In one example, the actuator is a pressure actuator that introduces or removes gas into the core. Light enters the optical fiber, is transmitted through the fiber toward the reflective surface of the droplet, and is reflected back through the fiber and exits at the same end of the photonic bandgap optical fiber that it entered. The fiber optic device can provide a continuously-variable optical path length of over 3.6 meters (corresponding to a continuously-variable true-time delay of over 12 ns, or 120 periods at a 10 GHz modulation frequency), with negligible wavelength dependence across the C and L bands.
Methods for producing a laser-guided underwater electrical discharge are provided. One or more electrodes defining a desired electrical discharge path are situated in a body of water and are attached to an external electrical power supply. A high-powered, intense laser beam is fired through one or more focusing lenses into the water. The laser beam forms an optical filament in the water, which in turn forms an ionized channel having a much greater conductivity than the surrounding water. An external power supply drives an electrical discharge along the path of the ionized channel due to its greater conductivity.
A laser apparatus configured for epitaxial-side-down mounting on a heat sink. The laser apparatus includes a semiconductor laser structure and at least one post on a substrate where the laser structure and post are separated from each other by a channel. The laser structure and the posts optionally are coated with a heat-spreading material layer and are configured so that the maximum height of the posts is about the same as the maximum height of the laser structure. When the laser apparatus is mounted to a heat sink in an epi-down configuration using solder applied to the top of the laser structure and the at least one post, the channels between the at least one post and the laser structure provide a relief flow path for the solder and ensure that the laser structure does not come directly into contact with the solder.
The present invention is a system that offers a capability to concentrate light from a large focal point onto a small spot on a detector. The system also offers off-axis capability should the system be moved, poorly pointed, off axis or jostled while in use. As designed, the present invention includes a half-ball lens having a front end and a back end, a compound parabolic concentrator (CPC) having a front end and a back end, wherein the front end of said CPC is adjacent to the back end of the half-ball lens such that the CPC is centered against the back end of the half-ball lens, and a detector, wherein the detector is adjacent to the back end of the CPC.
A photonic integrated chip having low insertion loss and facilitating alignment of the optical fiber with an optical device, preferably a waveguide or optical detector. The photonic integrated chip includes an optical fiber having a substantially spherical lens attached to one end. The device includes an etched via that receives the spherical lens attached to the optical fiber. An optical device is aligned with the via opposite the spherical lens such that light transmitted through the spherical lens is transmitted to the optical device. An anti-reflection coating is preferably applied on the end of the optical device abutting the via and the surface of the spherical lens to reduce scattering and insertion loss during transmission of data from the spherical lens to the optical device. Index matching fluid is alternatively disposed between the spherical lens and the via for this same purpose.