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Transparent glass composites containing nonlinear optical (NLO) and luminescent crystals are of significant interest for the optical materials science in spire of a lot of difficulties to synthesize high-quality NLO composites: refractive index and density matching! of glass matrix and crystal, controlled chemical interaction between them, absence of crystal aggregation, cords, bubbles, etc. Low density and refractive index, high second harmonic generation (SHG) activity, rather a high melting point allow to refer KNbSi2O7 ferroelectric to a promising candidate for using in the NLO glass composite technology. Manifestation of NLO properties of crystals in glass composites is established to depend drastically on glass matrix composition. During re-melting lead containing glasses react chemically with KNbSi2O7 forming pyrochlore Pb2Nb2O7 which is dissolved gradually up to nano-scaled state exhibiting moderate SHG efficiency by analogy with nanostructured glasses because of space modulation of polarizability originated from nano-sized inhomogeneities enriched with Pb and Nb. Using of TeO2-based glasses permits to match reft active indexes of glass matrix and crystal, reduce glass melting temperature and fabricate transparent composites containing micron and sub-micron crystals with high second harmonic generation activity. [ABSTRACT FROM AUTHOR]

Transparent glass composites containing nonlinear optical (NLO) and luminescent crystals are of significant interest for the optical materials science in spire of a lot of difficulties to synthesize high-quality NLO composites: refractive index and density matching! of glass matrix and crystal, controlled chemical interaction between them, absence of crystal aggregation, cords, bubbles, etc. Low density and refractive index, high second harmonic generation (SHG) activity, rather a high melting point allow to refer KNbSi2O7 ferroelectric to a promising candidate for using in the NLO glass composite technology. Manifestation of NLO properties of crystals in glass composites is established to depend drastically on glass matrix composition. During re-melting lead containing glasses react chemically with KNbSi2O7 forming pyrochlore Pb2Nb2O7 which is dissolved gradually up to nano-scaled state exhibiting moderate SHG efficiency by analogy with nanostructured glasses because of space modulation of polarizability originated from nano-sized inhomogeneities enriched with Pb and Nb. Using of TeO2-based glasses permits to match reft active indexes of glass matrix and crystal, reduce glass melting temperature and fabricate transparent composites containing micron and sub-micron crystals with high second harmonic generation activity. [ABSTRACT FROM AUTHOR]

Abstract: Ti–Al co-doped erbium tellurite glasses have been obtained by melting mixed Er2O3, TiO2 and TeO2 batches in Al2O3 crucibles. By crucible dissolution Al2O3 amounts from 11.5 to 18.6mol% were introduced in the synthesized glasses. Differential thermal analysis of glasses points to a strong dependence of glass transition temperature T g with the substitution extent of TeO2 by the doping oxides. No crystallization features are observed up to 450°C. The spectral features and decay kinetics of the infrared photoluminescence of erbium demonstrate the possibility to achieve more than 50% of quantum yield of light-emission at Er3+ concentrations as large as 1021 cm−3, with about 2ms of lifetime, 8×10−21 cm2 of stimulated emission cross section, and no saturation at pump power densities higher than 10kWcm−2. The study of the kinetics of Er–Er energy transfer suggests to ascribe these features to a particularly homogeneous dispersion of Er3+ ions in the modified tellurite network. Raman scattering measurements of the spectral distribution of vibrational modes evidence that the introduction of doping oxides leads to an increase of structural disorder without crystallization effects. [Copyright &y& Elsevier]