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Chemical and structural heterogeneities in Nd-doped oxynitride phosphate laser glasses
摘要: The application of oxynitride glasses in optics has been limited due the issues inherent in their preparation that result in bubbles, metallic inclusions or opacity. Although the synthesis of oxynitride phosphates is easier than in silicates, due to their lower melt viscosity, the remaining water in the form of OH causes, for instance, the neodymium luminescence to be negatively affected. We report on the preparation of oxynitride Nd phosphate glasses that are submitted first to a dehydroxylation, so that their structure and properties can be studied as a function of the nitrogen content taking a completely homogeneous OH-free glass as the starting point of each synthesis. Raman and Brillouin Spectroscopy confirmed the segregation in oxide and N-enriched regions, and NMR of the glasses has been used to calculate the O/P ratio from the distribution of P(O,N)4 groups. The difference between this and the experimental one obtained from the elemental analyses confirms the segregation in oxide and oxynitride regions that is produced during the ammonolysis of the phosphate glass. The oxynitride glass network could thus be considered a non-homogeneous mixture of the oxide and the nitrided phases that are segregated due to the non-randomness of the nitridation reaction.
关键词: Nitridation,Phosphate glasses,Laser glasses,Oxynitride glasses,Water
更新于2025-09-12 10:27:22
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Comparative Spectroscopic Investigation of Tm3+:Tellurite Glasses for 2-μm Lasing Applications
摘要: We performed a comparative spectroscopic analysis on three novel Tm3+:tellurite-based glasses with the following compositions Tm2O3:TeO2-ZnO (TeZnTm), Tm2O3:TeO2-Nb2O5 (TeNbTm), and Tm3+:TeO2-K2O-Nb2O5 (TeNbKTm), primarily for 2-μm laser applications. Tellurite glasses were prepared at different doping concentrations in order to investigate the effect of Tm3+ ion concentration as well as host composition on the stimulated emission cross sections and the luminescence quantum efficiencies. By performing Judd–Ofelt analysis, we determined the average radiative lifetimes of the 3H4 level to be 2.55 ± 0.07 ms, 2.76 ± 0.03 ms and 2.57 ± 0.20 ms for the TeZnTm, TeNbTm and TeNbKTm samples, respectively. We clearly observed the effect of the cross-relaxation, which becomes significant at higher Tm2O3 concentrations, leading to the quenching of 1460-nm emission and enhancement of 1860-nm emission. Furthermore, with increasing Tm2O3 concentrations, we observed a decrease in the fluorescence lifetimes as a result of the onset of non-radiative decay. For the 3H4 level, the highest obtained quantum efficiency was 32% for the samples with the lowest Tm2O3 ion concentration. For the 1860-nm emission band, the average emission cross section was determined to measure around 6.33 ± 0.34 × 10?21 cm2, revealing the potential of thulium-doped tellurite gain media for 2-μm laser applications in bulk and fiber configurations.
关键词: thulium-doped laser glasses,solid-state spectroscopy,lanthanide ion-doped glasses,glass lasers,2-micron lasers,thulium,tellurite glass
更新于2025-09-04 15:30:14