No abstract

New Sb2O3-based multicomponent heavy metal oxide glasses in the Sb2O3-Na2O-WO3-PbO system were prepared using a conventional melt-quenching technique. Glass formation behavior of these glasses and their thermal, physical and structural properties were investigated using X-ray diffraction (XRD), scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM/EDS), differential scanning calorimetry (DSC), UV-Vis-NIR spectroscopy and Fourier transform infrared (FTIR) spectroscopy analyses according to the increasing PbO concentration by keeping the Sb2O3/WO3 ratio constant. Thermal analysis of the glasses were realized in terms of glass transition temperature (Tg), crystallization temperature (Tc/Tp), glass stability against crystallization (∆T), activation energy of the glass transition reaction (Eg) and fragility parameter (m). Density (ρ), molar volume (VM), oxygen molar volume (VO), oxygen packing density (OPD), refractive index, band gap energy (Eg), average cross-link density (c n), number of bonds per unit volume (nb) and Poisson's ratio (μcal) values were calculated for the interpretation of physical and structural properties of the glasses. FTIR spectra of the glasses were evaluated in terms of structural transformations on the glass network.

International audienceWe study Antimonite glasses in the ternary systems Sb2O3-PbO-M2O (M = Li, Na, K). We have measured the density and refractive index according to the glass composition in this system. We have also measured the optical transmission in the UV-Vis and infrared range and the optical band gap. The influence of glass synthesis on extrinsic absorption has been studied. For the first time in this system, we have observed that stable glassy composition was drawn into a fiber, and the optical losses were determined in the 1-5 μm infrared region

International audienceSpectroscopic properties of Er3+ ions have been studied in the 60Sb2O3-20WO3-19Na2O-1Bi2O3 (SWNB) glasses doped with 0.25 and 0.50 mol% Er2O3 respectively. The Judd-Ofelt parameters measured from the absorption spectra have been used to calculate the radiative life-time (τr) and the stimulated emission cross section. The low phonon energy, a reduced quenching effect and a high quantum efficiency of 90% for the 1.53 μm expected laser emission into pumping at 980 nm are in favor of promising material laser application

International audienceHighly stable glasses in the (70 − x)Sb2O3[BOND]20Na2O[BOND]10ZnO[BOND]xEr2O3 (x = 0.25, 0.5, and 1.0 mol%) system have been prepared and investigated by UV-Vis-NIR absorption, near infrared photoluminescence and time-resolved spectroscopy. Judd-Ofelt study has been used to determine the intensity parameters (Ω2, Ω4, and Ω6), spontaneous emission probabilities, branching ratios, and radiative lifetimes (τR) related to the corresponding optical transitions of Er3+ ions. Details of the emission at ∼1530 nm and spectroscopic characteristics such as the stimulated emission cross-section (σe), effectiveband width (Δλeff), quantum efficiency, and the optical gain have been summarized, accounting the role of the increased Er content. The obtained results indicate that these new low phonon energy glasses could be used as a laser medium and for optical amplification in the 1.5 µm region. In particular, the composition containing 0.5 mol% Er2O3 exhibits optimal values of Ω2 (4.5 × 10−20 cm2), Δλeff = 57 nm, σe = 7.28 × 10−21 cm2, τmeas (3.36 ms), and quantum efficiency of the 4I13/2 level of Er3+ ions ∼71%

Bubbles defects have been always observed in sapphire crystals. Their distribution and size are strongly dependent on the growth conditions. We have studied the effect of the pulling rate on the bubbles' size and their distribution in sapphire rods grown by the micropulling down (μ-PD) technique. Using a central circular capillary die of shape factor 0.33, the bubbles' diameter decreased as a function of the pulling rate. The transmission decreased at a pulling rate greater than 1 mm/min.

No abstract

No abstract