Abstract: A Fourier-Transform Infrared (FTIR) spectrometer for operation in the mid- and long-wave infrared region (about 2-15 micron wavelengths) is disclosed. The FTIR spectrometer is composed of IR-transmitting fiber and uses a broadband IR source. A fiber stretcher is provided to provide a path difference between a first path and a second path having a sample associated therewith. Stretching of the fiber provides a path difference sufficient to generate an interferogram that can subsequently be analyzed to obtain information about a sample. A method for use of the apparatus of the invention is also disclosed. The method involves stretching of an IR-transmitting fiber to create a path difference sufficient to generate an interferogram. Various aspects of these features enable the construction of compact, portable spectrometers.

Abstract: A thermally stable chalcogenide glass, a process for making the same, and an optical fiber drawn therefrom are provided. A chalcogenide glass having the composition Ge(5?y)As(32?x)Se(59+x)Te(4+y) (0?y?1 and 0?x?2) is substantially free from crystallization when it is heated past the glass transition temperature Tg or drawn into optical fibers. A process for making the thermally stable chalcogenide glass includes purifying the components to remove oxides and scattering centers, batching the components in a preprocessed distillation ampoule, gettering oxygen impurities from the mixture, and heating the components to form a glass melt. An optical fiber formed from the chalcogenide glass is substantially free from crystallization and exhibits low signal loss in the near-infrared region, particularly at wavelengths of about 1.55 ?m.

Abstract: 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 ?m. 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.

Abstract: The present invention is generally directed to a bulk barium copper sulfur fluoride (BCSF) material made by combining Cu2S, BaS and BaF2, heating the ampoule between 400 and 550 ° C. for at least two hours, and then heating the ampoule at a temperature between 550 and 950 ° C. for at least two hours. The BCSF material may be doped with potassium, rubidium, or sodium. The present invention also provides for a BCSF transparent conductive thin film made by forming a sputter target by either hot pressing bulk BCSF or hot pressing Cu2S, BaS and BaF2 powders and sputtering a BCSF thin film from the target onto a substrate. The present invention is further directed to a p-type transparent conductive material comprising a thin film of BCSF on a substrate where the film has a conductivity of at least 1 S/cm. The substrate may be a plastic substrate, such as a polyethersulfone, polyethylene terephthalate, polyimide, or some other suitable plastic or polymeric substrate.

Abstract: A thermally stable chalcogenide glass, a process for making the same, and an optical fiber drawn therefrom are provided. A chalcogenide glass having the composition Ge(5?y)As(32?x)Se(59+x)Te(4+y) (0?y?1 and 0?x?2) is substantially free from crystallization when it is heated past the glass transition temperature Tg or drawn into optical fibers. A process for making the thermally stable chalcogenide glass includes purifying the components to remove oxides and scattering centers, batching the components in a preprocessed distillation ampoule, gettering oxygen impurities from the mixture, and heating the components to form a glass melt. An optical fiber formed from the chalcogenide glass is substantially free from crystallization and exhibits low signal loss in the near-infrared region, particularly at wavelengths of about 1.55 ?m.

Abstract: A thermally stable chalcogenide glass, a process for making the same, and an optical fiber drawn therefrom are provided. A chalcogenide glass having the composition Ge(5?y)As(32?x)Se(59+x)Te(4+y) (0?y?1 and 0?x?2) is substantially free from crystallization when it is heated past the glass transition temperature Tg or drawn into optical fibers. A process for making the thermally stable chalcogenide glass includes purifying the components to remove oxides and scattering centers, batching the components in a preprocessed distillation ampoule, gettering oxygen impurities from the mixture, and heating the components to form a glass melt. An optical fiber formed from the chalcogenide glass is substantially free from crystallization and exhibits low signal loss in the near-infrared region, particularly at wavelengths of about 1.55 ?m.

Abstract: This invention pertains to a composite of Spinel and BGG glass substrates and to process for bonding Spinel to BGG glass. The composite includes a Spinel and a BGG glass bonded together and having transmission in the visible and mid-infrared wavelength region. The process includes the step of heating them together above the softening temperature of the BGG glass, the composite having excellent, i.e., typically in excess of about 80%, transmission in the 0.5-5 wavelength region.

Abstract: The present invention is generally directed to a method of making chalcogenide glasses including holding the melt in a vertical furnace to promote homogenization and mixing; slow cooling the melt at less than 10° C. per minute; and sequentially quenching the melt from the top down in a controlled manner. Additionally, the present invention provides for the materials produced by such method. The present invention is also directed to a process for removing oxygen and hydrogen impurities from chalcogenide glass components using dynamic distillation.

Abstract: This invention pertains to product and process. The product is a transparent product of a density in excess 99.5% comprising spinel and having uniform mechanical properties. The process pertains to fabrication of a transparent spinel product comprising the steps of dissolving a sintering aid in water to form a neutral sintering aid solution, adding a suitable additive to the sintering aid solution, applying the sintering aid solution to spinel particles to form a spinel dispersion, sub-dividing or atomizing the spinel dispersion to form droplets comprising one or more spinel particles coated with the final spinel solution, drying the droplets to form dried coated particles comprising one or more spinel particles coated with a dried layer of the sintering aid, and densifying the dried coated particles to form a transparent spinel product having, uniform optical and mechanical properties in absence of grains of exaggerated size.

Abstract: Disclosed is a method of producing a spinel powder comprising preparing a double-hydroxide precursor precipitate then treating the precipitate with a washing agent, wherein said washing agent replaces water in said precipitate, then drying the precipitate to produce a hydroxide powder. The hydroxide powder is calcinated to produce an spinel powder that is essentially free of agglomeration.

Abstract: A particle having a magnesium aluminate core and a fluoride salt coating on the core. The particle has been heated in an oxidizing atmosphere to a temperature in the range of about 400° C. to about 750° C. A method of making a particle by mixing a magnesium aluminate core with a solution of a fluoride salt in a solvent to form a slurry and spraying the slurry into a drying column. The slurry enters the column as an aerosol under thermal conditions that avoid boiling the solvent. The thermal conditions in the column evaporate the solvent as the aerosol moves through the column to form a coating of the fluoride salt on the core while substantially avoiding spalling.

Abstract: A ceramic having at least about 90% by weight magnesium aluminate and having a bulk scattering and absorption loss of less than about 1/cm at any wavelength in a range of about 0.23 to about 5.3 microns or 0.2/cm at any wavelength in a range of about 0.27 to about 4.5 microns. A method of making a ceramic by providing a plurality of particles having a magnesium aluminate core and a fluoride salt coating; heating the particles in an oxidizing atmosphere to a temperature in the range of about 400° C. to about 750° C.; and sintering the particles to form a solid ceramic.

Abstract: This invention pertains to a chalcogenide glass of low optical loss that can be on the order of 30 dB/km or lower, and to a process for preparing the chalcogenide glass.

Abstract: An embodiment of the invention includes a particle. The particle includes a first yttria core; and a fluoride salt coating on the first yttria core. The coating is sufficiently continuous to prevent a large number of sites where a second yttria core may come into contact with the first yttria core. Optionally, the particle has been heated in an oxidizing atmosphere to a temperature in the range of about 400° C. to about 750° C. Optionally, the particle is substantially free of at least one of carbon-containing species and water. Optionally, the fluoride salt is lithium fluoride. Optionally, the fluoride salt is aluminum fluoride.

Abstract: This invention pertains to a chalcogenide glass of low optical loss that can be on the order of 30 dB/km or lower, and to a process for preparing the chalcogenide glass.

Abstract: A waveguide amplifier, disposed on a substrate, composed of sputtered film of chalcogenide glass doped with Erbium is disclosed. The amplifier includes a substrate, a thick film of chalcogenide glass disposed on the substrate, a pumping device, and an optical combining device, wherein the waveguide is operable to amplify the optically combined signal. This type of amplifier has been shown to be compact and cost-effective, in addition to being transparent in the mid-IR range as a result of the low phonon energy of chalcogenide glass.

Abstract: This invention pertains to a scene projection system and a method for projecting a scene that can simulate light temperature of above 2000 K. The system comprises of a light source part for generating light at a lower wavelength; a means part for individually controlling dynamic range, contrast, brightness, temporal characteristics and temporal dynamics of the light; a rare earth doped fiber part that re-emits the output light at a higher wavelength; and a means part for conveying light between its parts. The method comprises steps of generating light at a lower wavelength; individually controlling temporal characteristics, temporal dynamics, brightness and contrast of the light; passing the light through a rare earth-doped fiber; and re-emitting the light at a higher wavelength.

Abstract: 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.

Abstract: 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.

Abstract: The coating method includes the steps of dissolving coating precursor(s) in a solvent to form a precursor solution: adding with mixing a miscible diluent to the precursor solution to form a coating solution; admixing solid particles to the coating solution to form a coating slurry, with the particles surrounded with the coating solution; spraying the coating slurry to form droplets containing at least one particle; passing the droplets through a drying zone where the droplets are dried and form dry particles coated with a coating material formed from the coating precursor(s); heat-treating the coating material on the particles emanating from the drying zone to remove volatile matter on the coating material, to improve integrity of the coating material and/or to effect another objective; and collecting dry coated particles.