The Experts below are selected from a list of 48 Experts worldwide ranked by ideXlab platform

Joris Lousteau - One of the best experts on this subject based on the ideXlab platform.

  • rare earth ion doped teo2 and geo2 glasses as laser materials
    Progress in Materials Science, 2012
    Co-Authors: Billy Richards, Gin Jose, Toney Teddyfernandez, Purushottam Joshi, Xin Jiang, Joris Lousteau
    Abstract:

    Abstract Germanium oxide (GeO 2 ) and tellurium oxide (TeO 2 ) based glasses are classed as the heavy metal oxide glasses, with phonon energies ranging between 740 cm −1 and 880 cm −1 . These two types of glasses exhibit unique combinations of optical and spectroscopic properties, together with their attractive environmental resistance and mechanical properties. Engineering such a combination of structural, optical and spectroscopic properties is only feasible as a result of structural variability in these two types of glasses, since more than one structural units (TeO 4 bi-pyramid, TeO 3 trigonal pyramid, and TeO 3+ δ polyhedra) in tellurite and (GeO 4 tetrahedron, GeO 3 octahedron) in GeO 2 based glasses may exist, depending on composition. The presence of multiple structural moities creates a range of dipole environments which is ideal for Engineering broad spectral bandwidth rare-earth ion doped photonic device materials, suitable for laser and amplifier devices. Tellurite glasses were discovered in 1952, but remained virtually unknown to materials and device engineers until 1994 when unusual spectroscopic, nonlinear and dispersion properties of alkali and alkaline earth modified tellurite glasses and Fibres were reported. Detailed spectroscopic analysis of Pr 3+ , Nd 3+ , Er 3+ , and Tm 3+ doped tellurite glasses revealed its potential for laser and amplifier devices for optical communication wavelengths. This review summarises the thermal and viscosity properties of tellurite and germanate glasses for Fibre fabrication and compares the linear loss for near and mid-IR device Engineering. The aspects of glass preform fabrication for Fibre Engineering is discussed by emphasising the raw materials processing with casting of preforms and Fibre fabrication. The spectroscopic properties of tellurite and germanate glasses have been analysed with special emphasis on oscillator strength and radiative rate characteristics for visible, near IR and mid-IR emission. The review also compares the latest results in the Engineering of lasers and amplifiers, based on Fibres for optical communication and mid-IR. The achievements in the areas of near-IR waveguide and mid-IR bulk glass, Fibre, and waveguide lasers are discussed. The latest landmark results in mode-locked 2 μm bulk glass lasers sets the precedence for Engineering nonlinear and other laser devices for accessing the inaccessible parts of the mid-IR spectrum and discovering new applications for the future.

  • Investigation on germanium oxide-based glasses for infrared optical Fibre development
    Optical Materials, 2009
    Co-Authors: Xin Jiang, Billy Richards, Joris Lousteau, Animesh Jha
    Abstract:

    Abstract We demonstrate the suitability of GeO 2 for Fibre Engineering by compositional modifications of core and cladding glasses using the rod-in-tube technique, which have been matched for Fibre drawing. The methods adopted for identifying the core–clad combination (56GeO 2 –31PbO–9Na 2 O–4Ga 2 O 3 and 55GeO 2 –30PbO–11Na 2 O–4Ga 2 O 3 ) are explained, based on the thermal, viscosity, and optical properties. We specially point out to the relatively high transformation temperature range ( T g  > 380 °C) of the glass, which is suitable for chemical sensing and metrological applications in the 150–200 °C. The total intrinsic loss is compared with the measured loss in multi- and single-mode Fibres from 0.532 to 2.02 μm, with loss less than 2.5 dB m −1 in the 1000–1600 nm range. The origin of larger loss outside this region is explained.

Billy Richards - One of the best experts on this subject based on the ideXlab platform.

  • rare earth ion doped teo2 and geo2 glasses as laser materials
    Progress in Materials Science, 2012
    Co-Authors: Billy Richards, Gin Jose, Toney Teddyfernandez, Purushottam Joshi, Xin Jiang, Joris Lousteau
    Abstract:

    Abstract Germanium oxide (GeO 2 ) and tellurium oxide (TeO 2 ) based glasses are classed as the heavy metal oxide glasses, with phonon energies ranging between 740 cm −1 and 880 cm −1 . These two types of glasses exhibit unique combinations of optical and spectroscopic properties, together with their attractive environmental resistance and mechanical properties. Engineering such a combination of structural, optical and spectroscopic properties is only feasible as a result of structural variability in these two types of glasses, since more than one structural units (TeO 4 bi-pyramid, TeO 3 trigonal pyramid, and TeO 3+ δ polyhedra) in tellurite and (GeO 4 tetrahedron, GeO 3 octahedron) in GeO 2 based glasses may exist, depending on composition. The presence of multiple structural moities creates a range of dipole environments which is ideal for Engineering broad spectral bandwidth rare-earth ion doped photonic device materials, suitable for laser and amplifier devices. Tellurite glasses were discovered in 1952, but remained virtually unknown to materials and device engineers until 1994 when unusual spectroscopic, nonlinear and dispersion properties of alkali and alkaline earth modified tellurite glasses and Fibres were reported. Detailed spectroscopic analysis of Pr 3+ , Nd 3+ , Er 3+ , and Tm 3+ doped tellurite glasses revealed its potential for laser and amplifier devices for optical communication wavelengths. This review summarises the thermal and viscosity properties of tellurite and germanate glasses for Fibre fabrication and compares the linear loss for near and mid-IR device Engineering. The aspects of glass preform fabrication for Fibre Engineering is discussed by emphasising the raw materials processing with casting of preforms and Fibre fabrication. The spectroscopic properties of tellurite and germanate glasses have been analysed with special emphasis on oscillator strength and radiative rate characteristics for visible, near IR and mid-IR emission. The review also compares the latest results in the Engineering of lasers and amplifiers, based on Fibres for optical communication and mid-IR. The achievements in the areas of near-IR waveguide and mid-IR bulk glass, Fibre, and waveguide lasers are discussed. The latest landmark results in mode-locked 2 μm bulk glass lasers sets the precedence for Engineering nonlinear and other laser devices for accessing the inaccessible parts of the mid-IR spectrum and discovering new applications for the future.

  • Investigation on germanium oxide-based glasses for infrared optical Fibre development
    Optical Materials, 2009
    Co-Authors: Xin Jiang, Billy Richards, Joris Lousteau, Animesh Jha
    Abstract:

    Abstract We demonstrate the suitability of GeO 2 for Fibre Engineering by compositional modifications of core and cladding glasses using the rod-in-tube technique, which have been matched for Fibre drawing. The methods adopted for identifying the core–clad combination (56GeO 2 –31PbO–9Na 2 O–4Ga 2 O 3 and 55GeO 2 –30PbO–11Na 2 O–4Ga 2 O 3 ) are explained, based on the thermal, viscosity, and optical properties. We specially point out to the relatively high transformation temperature range ( T g  > 380 °C) of the glass, which is suitable for chemical sensing and metrological applications in the 150–200 °C. The total intrinsic loss is compared with the measured loss in multi- and single-mode Fibres from 0.532 to 2.02 μm, with loss less than 2.5 dB m −1 in the 1000–1600 nm range. The origin of larger loss outside this region is explained.

Xin Jiang - One of the best experts on this subject based on the ideXlab platform.

  • rare earth ion doped teo2 and geo2 glasses as laser materials
    Progress in Materials Science, 2012
    Co-Authors: Billy Richards, Gin Jose, Toney Teddyfernandez, Purushottam Joshi, Xin Jiang, Joris Lousteau
    Abstract:

    Abstract Germanium oxide (GeO 2 ) and tellurium oxide (TeO 2 ) based glasses are classed as the heavy metal oxide glasses, with phonon energies ranging between 740 cm −1 and 880 cm −1 . These two types of glasses exhibit unique combinations of optical and spectroscopic properties, together with their attractive environmental resistance and mechanical properties. Engineering such a combination of structural, optical and spectroscopic properties is only feasible as a result of structural variability in these two types of glasses, since more than one structural units (TeO 4 bi-pyramid, TeO 3 trigonal pyramid, and TeO 3+ δ polyhedra) in tellurite and (GeO 4 tetrahedron, GeO 3 octahedron) in GeO 2 based glasses may exist, depending on composition. The presence of multiple structural moities creates a range of dipole environments which is ideal for Engineering broad spectral bandwidth rare-earth ion doped photonic device materials, suitable for laser and amplifier devices. Tellurite glasses were discovered in 1952, but remained virtually unknown to materials and device engineers until 1994 when unusual spectroscopic, nonlinear and dispersion properties of alkali and alkaline earth modified tellurite glasses and Fibres were reported. Detailed spectroscopic analysis of Pr 3+ , Nd 3+ , Er 3+ , and Tm 3+ doped tellurite glasses revealed its potential for laser and amplifier devices for optical communication wavelengths. This review summarises the thermal and viscosity properties of tellurite and germanate glasses for Fibre fabrication and compares the linear loss for near and mid-IR device Engineering. The aspects of glass preform fabrication for Fibre Engineering is discussed by emphasising the raw materials processing with casting of preforms and Fibre fabrication. The spectroscopic properties of tellurite and germanate glasses have been analysed with special emphasis on oscillator strength and radiative rate characteristics for visible, near IR and mid-IR emission. The review also compares the latest results in the Engineering of lasers and amplifiers, based on Fibres for optical communication and mid-IR. The achievements in the areas of near-IR waveguide and mid-IR bulk glass, Fibre, and waveguide lasers are discussed. The latest landmark results in mode-locked 2 μm bulk glass lasers sets the precedence for Engineering nonlinear and other laser devices for accessing the inaccessible parts of the mid-IR spectrum and discovering new applications for the future.

  • Investigation on germanium oxide-based glasses for infrared optical Fibre development
    Optical Materials, 2009
    Co-Authors: Xin Jiang, Billy Richards, Joris Lousteau, Animesh Jha
    Abstract:

    Abstract We demonstrate the suitability of GeO 2 for Fibre Engineering by compositional modifications of core and cladding glasses using the rod-in-tube technique, which have been matched for Fibre drawing. The methods adopted for identifying the core–clad combination (56GeO 2 –31PbO–9Na 2 O–4Ga 2 O 3 and 55GeO 2 –30PbO–11Na 2 O–4Ga 2 O 3 ) are explained, based on the thermal, viscosity, and optical properties. We specially point out to the relatively high transformation temperature range ( T g  > 380 °C) of the glass, which is suitable for chemical sensing and metrological applications in the 150–200 °C. The total intrinsic loss is compared with the measured loss in multi- and single-mode Fibres from 0.532 to 2.02 μm, with loss less than 2.5 dB m −1 in the 1000–1600 nm range. The origin of larger loss outside this region is explained.

Animesh Jha - One of the best experts on this subject based on the ideXlab platform.

  • Investigation on germanium oxide-based glasses for infrared optical Fibre development
    Optical Materials, 2009
    Co-Authors: Xin Jiang, Billy Richards, Joris Lousteau, Animesh Jha
    Abstract:

    Abstract We demonstrate the suitability of GeO 2 for Fibre Engineering by compositional modifications of core and cladding glasses using the rod-in-tube technique, which have been matched for Fibre drawing. The methods adopted for identifying the core–clad combination (56GeO 2 –31PbO–9Na 2 O–4Ga 2 O 3 and 55GeO 2 –30PbO–11Na 2 O–4Ga 2 O 3 ) are explained, based on the thermal, viscosity, and optical properties. We specially point out to the relatively high transformation temperature range ( T g  > 380 °C) of the glass, which is suitable for chemical sensing and metrological applications in the 150–200 °C. The total intrinsic loss is compared with the measured loss in multi- and single-mode Fibres from 0.532 to 2.02 μm, with loss less than 2.5 dB m −1 in the 1000–1600 nm range. The origin of larger loss outside this region is explained.

Mark J. Van Raaij - One of the best experts on this subject based on the ideXlab platform.

  • Adenovirus Fibre Shaft Sequences Fold Into the Native Triple Beta-Spiral Fold When N-Terminally Fused to the Bacteriophage T4 Fibritin Foldon Trimerisation Motif
    Journal of molecular biology, 2004
    Co-Authors: Katerina Papanikolopoulou, Susana C. M. Teixeira, Hassan Belrhali, V. Trevor Forsyth, Anna Mitraki, Mark J. Van Raaij
    Abstract:

    Adenovirus Fibres are trimeric proteins that consist of a globular C-terminal domain, a central fibrous shaft and an N-terminal part that attaches to the viral capsid. In the presence of the globular C-terminal domain, which is necessary for correct trimerisation, the shaft segment adopts a triple beta-spiral conformation. We have replaced the head of the Fibre by the trimerisation domain of the bacteriophage T4 fibritin, the foldon. Two different fusion constructs were made and crystallised, one with an eight amino acid residue linker and one with a linker of only two residues. X-ray crystallographic studies of both fusion proteins shows that residues 319-391 of the adenovirus type 2 Fibre shaft fold into a triple beta-spiral fold indistinguishable from the native structure, although this is now resolved at a higher resolution of 1.9 A. The foldon residues 458-483 also adopt their natural structure. The intervening linkers are not well ordered in the crystal structures. This work shows that the shaft sequences retain their capacity to fold into their native beta-spiral fibrous fold when fused to a foreign C-terminal trimerisation motif. It provides a structural basis to artificially trimerise longer adenovirus shaft segments and segments from other trimeric beta-structured Fibre proteins. Such artificial fibrous constructs, amenable to crystallisation and solution studies, can offer tractable model systems for the study of beta-fibrous structure. They can also prove useful for gene therapy and Fibre Engineering applications.