Abstract: A method of measuring temperature includes positioning an optical fiber in contact with an object or in an environment having a temperature to be determined, where the optical fiber comprises a core surrounded by a cladding; the core comprises an alkaline-earth fluorosilicate glass including defects, and the cladding comprises a silica glass. Infrared light is supplied to the optical fiber, thereby electronically exciting the defects. Green light emitted from the defects is detected, and an intensity value of the green light is obtained and converted to a temperature value for the optical fiber, whereby the temperature of the object or environment is determined. The green light may be detected along a length of the optical fiber, and a plurality of intensity values may be converted to a plurality of temperature values along the fiber length, thereby obtaining a distributed measurement of the temperature of the object or environment.

Abstract: The present application is generally directed to compositions and methods for forming glass matrices which may exhibit anti-Stokes fluorescence. The glass matrices of the present disclosure are formed such that a thermal characteristic can be tuned, such as the extent to which cooling by anti-Stokes fluorescence occurs. Optical fibers, such as those used in lasers, may be formed out of the presently described glass matrices. In embodiments, glass matrices of the present disclosure may form a cladding layer around an optical fiber. Further, glass matrices of the present disclosure may be used in combination with a device or to provide cooling to said device.

Abstract: Disclosed are methods for formation of a fiber and fibers that can be formed according to the methods. Formation methods incorporate a “molten core flux method” whereby a solid primary core material is combined with a solid secondary flux material in a multi-phase preform core. In some embodiments, the multi-phase preform core has a liquidus temperature that is reduced relative to the melting temperature of at least the primary core material. A homogeneous liquid melt of the preform core can exhibit a sufficiently low vapor pressure such that a fiber preform incorporating the materials in the core can be thermally drawn. Upon cooling and solidification of the homogeneous core melt, separation of the core components can occur via recrystallization, with one phase being that of the desired primary core material. Methods can be particularly beneficial for forming fibers incorporating high vapor pressure semiconductor materials, e.g., ZnSe or GaAs, in the fiber core.

Abstract: A fiber includes a core and cladding, both of which may have temperature dependent indices of refraction. The materials and size of the core and cladding may be selected such that as the temperature of the core and/or cladding is heated above room temperature, the fiber transitions from supporting multimode optical waveguiding to supporting single mode waveguiding.

Abstract: A method of measuring temperature includes positioning an optical fiber in contact with an object or in an environment having a temperature to be determined, where the optical fiber comprises a core surrounded by a cladding; the core comprises an alkaline-earth fluorosilicate glass including defects, and the cladding comprises a silica glass. Infrared light is supplied to the optical fiber, thereby electronically exciting the defects. Green light emitted from the defects is detected, and an intensity value of the green light is obtained and converted to a temperature value for the optical fiber, whereby the temperature of the object or environment is determined. The green light may be detected along a length of the optical fiber, and a plurality of intensity values may be converted to a plurality of temperature values along the fiber length, thereby obtaining a distributed measurement of the temperature of the object or environment.

Abstract: A microheater comprises an optical fiber including a rare earth-doped glass core surrounded by a glass cladding. The rare earth-doped glass core comprises a rare earth dopant at a concentration sufficient for luminescence quenching such that, when the rare earth dopant is pumped with light at an absorption band wavelength, at least about 90% of absorbed pump light is converted into heat.

Abstract: Disclosed are methods for formation of a fiber and fibers that can be formed according to the methods. Formation methods incorporate a “molten core flux method” whereby a solid primary core material is combined with a solid secondary flux material in a multi-phase preform core. In some embodiments, the multi-phase preform core has a liquidus temperature that is reduced relative to the melting temperature of at least the primary core material. A homogeneous liquid melt of the preform core can exhibit a sufficiently low vapor pressure such that a fiber preform incorporating the materials in the core can be thermally drawn. Upon cooling and solidification of the homogeneous core melt, separation of the core components can occur via recrystallization, with one phase being that of the desired primary core material. Methods can be particularly beneficial for forming fibers incorporating high vapor pressure semiconductor materials, e.g., ZnSe or GaAs, in the fiber core.

Abstract: A rare earth-doped optical fiber comprises a fluorosilicate core surrounded by a silica cladding, where the fluorosilicate core comprises an alkaline-earth fluoro-alumino-silicate glass, such as a strontium fluoro-alumino-silicate glass. The rare earth-doped optical fiber may be useful as a high-power fiber laser and/or fiber amplifier. A method of making a rare earth-doped optical fiber comprises: inserting a powder mixture comprising YbF3, SrF2, and Al2O3 into a silica tube; after inserting the powder mixture, heating the silica tube to a temperature of at least about 2000° C., some or all of the powder mixture undergoing melting; drawing the silica tube to obtain a reduced-diameter fiber; and cooling the reduced-diameter fiber. Thus, a rare earth-doped optical fiber comprising a fluorosilicate core surrounded by a silica cladding is formed.

Abstract: A fiber includes a core and cladding, both of which may have temperature dependent indices of refraction. The materials and size of the core and cladding may be selected such that as the temperature of the core and/or cladding is heated above room temperature, the fiber transitions from supporting multimode optical waveguiding to supporting single mode waveguiding.

Abstract: A microheater comprises an optical fiber including a rare earth-doped glass core surrounded by a glass cladding. The rare earth-doped glass core comprises a rare earth dopant at a concentration sufficient for luminescence quenching such that, when the rare earth dopant is pumped with light at an absorption band wavelength, at least about 90% of absorbed pump light is converted into heat.

Abstract: A rare earth-doped optical fiber comprises a fluorosilicate core surrounded by a silica cladding, where the fluorosilicate core comprises an alkaline-earth fluoro-alumino-silicate glass, such as a strontium fluoro-alumino-silicate glass. The rare earth-doped optical fiber may be useful as a high-power fiber laser and/or fiber amplifier. A method of making a rare earth-doped optical fiber comprises: inserting a powder mixture comprising YbF3, SrF2, and Al2O3 into a silica tube; after inserting the powder mixture, heating the silica tube to a temperature of at least about 2000° C., some or all of the powder mixture undergoing melting; drawing the silica tube to obtain a reduced-diameter fiber; and cooling the reduced-diameter fiber. Thus, a rare earth-doped optical fiber comprising a fluorosilicate core surrounded by a silica cladding is formed.

Abstract: Disclosed is an optical fiber formed from a preform that includes a clad component and a core component. The core component includes one or more precursor core materials. The precursor core materials and the clad materials are selected such that that the photoelastic constants of at least one precursor core material and the clad material are of opposite sign resulting in a final glass optical fiber of tailored Brillouin performance. The clad material may include an oxide glass having a positive photoelastic constant and the core component may include a precursor core material that has a negative photoelastic constant. During formation, the precursor core material can melt and interact with clad material that precipitates into the core to form a glass of at least one tailored Brillouin property, such as very low Brillouin gain.

Abstract: One embodiment of the invention includes a method for forming an optical fiber. The method comprises providing a preform having a core material and a glass cladding material surrounding the core material. The method also comprises drawing the preform at a temperature that is greater than a melting temperature of the core material to form a drawn fiber. The method further comprises cooling the drawn fiber to form the optical fiber having a crystalline fiber core and a cladding that surrounds the crystalline fiber core and extends axially along a length of the crystalline fiber core.

Abstract: Disclosed is an optical fiber formed from a preform that includes a clad component and a core component. The core component includes one or more precursor core materials. The precursor core materials and the clad materials are selected such that that the photoelastic constants of at least one precursor core material and the clad material are of opposite sign resulting in a final glass optical fiber of tailored Brillouin performance. The clad material may include an oxide glass having a positive photoelastic constant and the core component may include a precursor core material that has a negative photoelastic constant. During formation, the precursor core material can melt and interact with clad material that precipitates into the core to form a glass of at least one tailored Brillouin property, such as very low Brillouin gain.

Abstract: One embodiment of the invention includes a method for forming an optical fiber. The method comprises providing a preform having a core material and a glass cladding material surrounding the core material. The method also comprises drawing the preform at a temperature that is greater than a melting temperature of the core material to form a drawn fiber. The method further comprises cooling the drawn fiber to form the optical fiber having a crystalline fiber core and a cladding that surrounds the crystalline fiber core and extends axially along a length of the crystalline fiber core.

Abstract: The disclosure provides compositions prepared by combining nanomaterials with a halide-containing polymer, thereby forming a combined polymer matrix having dispersed nanomaterials within the matrix. The nanomaterials may be carbon-based nanotubes, in some applications. A halide-containing monomer is combined with nanotubes, and then polymerized in some compositions. In other applications, a halide-containing polymer is solution processed with nanotubes to form useful compositions in the invention. Also disclosed are probes for near field detection of radiation.

Abstract: The disclosure provides compositions prepared by combining nanomaterials with a halide-containing polymer, thereby forming a combined polymer matrix having dispersed nanomaterials within the matrix. The nanomaterials may be carbon-based nanotubes, in some applications. A halide-containing monomer is combined with nanotubes, and then polymerized in some compositions. In other applications, a halide-containing polymer is solution processed with nanotubes to form useful compositions in the invention. Also disclosed are probes for near field detection of radiation.

Abstract: Optically transparent composite materials in which solid solution inorganic nanoparticles are dispersed in a host matrix inert thereto, wherein the nanoparticles are doped with one or more active ions at a level up to about 60 mole % and consist of particles having a dispersed particle size between about 1 and about 100 nm, and the composite material with the nanoparticles dispersed therein is optically transparent to wavelengths at which excitation, fluorescence or luminescence of the active ions occur. Luminescent devices incorporating the composite materials are also disclosed.

Abstract: The disclosure provides compositions prepared by combining nanomaterials with a halide-containing polymer, thereby forming a combined polymer matrix having dispersed nanomaterials within the matrix. The nanomaterials may be carbon-based nanotubes, in some applications. A halide-containing monomer is combined with nanotubes, and then polymerized in some compositions. In other applications, a halide-containing polymer is solution processed with nanotubes to form useful compositions in the invention. Also disclosed are probes for near field detection of radiation.

Abstract: Methods, systems and devices for a waveguide pumping gain guided index antiguided fiber laser having a fiber selected for a refractive index crossover at a wavelength between a pump wavelength and a laser emission wavelength. A waveguide pumping system pumps a light having a pump wavelength into the fiber allowing a laser light to be captured by a gain guided process in the core while the pump light, propagating in the cladding is coupled to the core. The fiber selection includes selecting a fiber with a cladding material having a refractive index less than a core material refractive index for a pump wavelength and a core refractive index at the laser emission wavelength is less than the cladding refractive index at the same laser emission wavelength to allow the pump light to propagate through the cladding as a conventional wave guided fiber laser, white the laser emission is captured within the core as an index antiguided, gain guided wave.