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  • 1
    Electronic Resource
    Electronic Resource
    Improved Composition for Sol-Gel Rare-Earth Doped Planar Waveguides (1997)
    Springer
    Journal of sol gel science and technology 8 (1997), S. 1013-1016 
    Details
    ISSN: 1573-4846
    Keywords: sol-gel ; neodymium and erbium doped planar waveguide ; fluorescence lifetime measurement ; phosphorous and aluminium codoping
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A multilayer sol-gel process has been developed in order to make highly doped rare-earth planar waveguides on silica or silicon substrates. Starting with a small range of constituents, such as SiO2, TiO2, P2O5 and Al2O3, we show that a large variety of gel compositions, with different spectroscopic behaviour, can be made when doped with rare-earths. We have doped the sol-gel films with neodymium and we have optimized their compositions by measuring the neodymium fluorescence lifetime. For a composition with 10 atom% of phosphorous, the lifetime evolution with neodymium concentration was studied and a quenching concentration was found at 1% of neodymium. We have also shown the strong influence of phosphorous or aluminium in the sol composition on the fluorescence lifetime, for a given neodymium concentration. First results on similar planar waveguides, doped with erbium, are also presented. The stability of the fluorescence lifetime over a long period of time is an other important point to be checked for these new materials: the lifetime evolution over a 9 months measurement period is presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018374005608
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  • 2
    Electronic Resource
    Electronic Resource
    Improved composition for sol-gel rare-earth doped planar waveguides (1997)
    Springer
    Journal of sol gel science and technology 8 (1997), S. 1013-1016 
    Details
    ISSN: 1573-4846
    Keywords: sol-gel ; neodymium and erbium doped planar waveguide ; fluorescence lifetime measurement ; phosphorous and aluminium codoping
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A multilayer sol-gel process has been developed in order to make highly doped rare-earth planar waveguides on silica or silicon substrates. Starting with a small range of constituents, such as SiO2, TiO2, P2O5 and Al2O3, we show that a large variety of gel compositions, with different spectroscopic behaviour, can be made when doped with rare-earths. We have doped the sol-gel films with neodymium and we have optimized their compositions by measuring the neodymium fluorescence lifetime. For a composition with 10 atom% of phosphorous, the lifetime evolution with neodymium concentration was studied and a quenching concentration was found at 1% of neodymium. We have also shown the strong influence of phosphorous or aluminium in the sol composition on the fluorescence lifetime, for a given neodymium concentration. First results on similar planar waveguides, doped with erbium, are also presented. The stability of the fluorescence lifetime over a long period of time is an other important point to be checked for these new materials: the lifetime evolution over a 9 months measurement period is presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02436976
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  • 3
    Electronic Resource
    Electronic Resource
    Atomic Force Microscopy Study of NaOH Corroded Al2O3-TiO2-SiO2 Coatings on Glass (1998)
    Springer
    Journal of sol gel science and technology 13 (1998), S. 763-767 
    Details
    ISSN: 1573-4846
    Keywords: sol-gel ; coatings ; corrosion ; morphology ; atomic force microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Atomic force microscopy (AFM) was used to study the performance of ≈80 nm thick Al2O3-TiO2-SiO2 sol-gel coatings on glass substrates following corrosion in 1 M NaOH solutions at 60°C. The as-prepared coatings were homogeneous on a nanoscale and displayed the “glass pattern” before corrosion. Layers with different compositions behaved differently during the corrosion process. Thus, TiO2 or TiO2-dominated layers had tetragonal-like crystals on their surfaces after corrosion, possibly of anatase composition. On the other hand, layers with a molar ratio Al2O3 : SiO2 near 1 : 2 displayed a pseudo-hexagonal morphology, possibly with a nepheline (Na2O · Al2O3 · 2SiO2) composition. Layers of 5Al2O3-40TiO2-55SiO 2 were corroded is a stepwise fashion and had no special surface morphology.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008669728556
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  • 4
    Electronic Resource
    Electronic Resource
    Er3+-doped Multicomponent Silicate Glass Planar Waveguides Prepared by Sol-Gel Processing (1999)
    Springer
    Journal of sol gel science and technology 14 (1999), S. 209-216 
    Details
    ISSN: 1573-4846
    Keywords: sol-gel ; silica-titania films ; planar waveguides ; Er doping ; fluorescence lifetime
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Erbium doped silica-titania planar waveguides, co-doped with ytterbium and aluminum, have been prepared by sol-gel processing, using multilayer spin-coating deposition on silicon or silica glass substrates. The Er3+ doping level varied between 0 and 2 at.%, while Yb3+ varied from 0 to 3 at.%. Aluminum was incorporated up to 15 at.% Al and it was found to have no significant effect on the refractive index of the silica-titania (80 : 20 mol%) matrix. The Er3+ fluorescence emission was flat within ±0.5 dB, between 1520 and 1560 nm. The corresponding 4I13/2 metastable level lifetime was found to decrease from 6.1 to 3.5 ms, as the Er concentration increased from 0.1 to 0.5 at.%, for films co-doped with 0.5 at.% Yb and 10 at.% Al and the fluorescence decay was essentially single exponential below a Er quenching concentration of 0.5 at.% (1.1 × 1020 ions/cm3). The lifetime appears to be limited by Er-Er interactions at higher rare-earth ion concentrations and by residual OH species in the sol-gel derived waveguides. Vacuum heat treatment at a temperature near 570°C was somewhat effective in increasing the Er fluorescence lifetime, whereas reactive atmosphere processing in CCl4 or Cl2 at a similar temperature appeared to be less effective.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008794202103
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