Structural and optical properties of Eu3+ doped barium-gallo-germanate glasses modified with antimony and tellurium oxides were investigated. Barium ions are gradually replaced by antimony and tellurium ions to create two glass series. Structural properties of prepared series were established with help of FT-IR spectroscopy, X-ray diffraction method and observation under Scanning Electron Microscope (SEM). MIR spectra of studied glasses indicate a tendency to glass structure polymerization through the observed shift of main band assigned to Ge-O-Ge and Ge-O bonds vibrations. Simultaneously luminescence spectrum of Eu3+ ion (Electric/Magnetic – ED/EM dipole transition intensity ratio) for both glass series presented the increasing tendency to ordering of Eu3+ local environment. It was also proved that tetrahedral [TeO4] units were created in glass structure which were modified with TeO2 when addition exceed 10 mol%. The result indicates decrease of ED/MD ratio as a function of TeO2 content above its 10 mol%.
The article presents the analysis of local field effect in antimony-germanate-silicate glass doped with europium and silver ions. The effect of AgNO3 concentration on structural and luminescent properties of fabricated glass doped with 0.2 mol. % Eu2O3 have been investigated. XRD and scanning electron microscopy measurements shown that fabricated glass are fully amorphous and the structure of each samples are uniform. Based on the infrared analysis visible effect of Ag ions on MIR absorbance was not observed. According to the luminescence analysis, in glasses with Ag excited at 395 nm the slightly increase of 5D0 → 7F2 transition (613 nm) in Eu3+ ions have been observed only after melting process.
In this paper antimony-germanate oxide glasses doped with Er3+ and co-doped with Er3+/Ag ions were synthesized and measured in terms of absorbance and near-infrared emission parameters. Series of glasses with different molar concentration of erbium oxide led to the optimal rare earth ion content equal to 0.8 mol% Er2O3. The effect of the incorporation silver ions to the glass matrix on the absorption spectrum in the UV range (Ag: S0 → S1, 350 nm) was confirmed formation of silver ions as a nanoparticles or nanoclusters. In samples co-doped with Er3+/Ag ions decrease of near-infrared luminescence intensity has been observed indicating predominant energy transfer from erbium to silver ions (Er3+ → Ag).
In the paper the analysis of white upconversion luminescence obtained as a result superposition of emission bands in germanate glass and double- clad optical fiber co-doped with Yb3+/Tm3+/Ho3+ and Yb3+/Er3+/Tm3+ have been presented. Calculated CIE coordinates for glass co-doped with 0.5Yb2O3/0.4Tm2O3 /0.1 Ho2O3 were x=0.311, y=0.337, Ppump=2.5W and for 0.5Yb2O3/0.25Tm2O3 /0.25Er2O3 co-doped were: x = 252, y = 502. Influence of pump power on the colour coordinates have been also investigated. Thus Yb3+/Tm3+/Ho3+ co-dopant system in germanate glass was used as a core of double-clad optical fiber. Comparative analyses showed differences in luminescence spectra shape of bulk glass and fabricated 0.5Yb2O3/0.4Tm2O3 /0.1Ho2O3 triply doped double – clad optical fiber. Due to partial reabsorption of blue part of amplified spontaneous emission signal propagating band in optical fiber is shifted by 4 nm towards shorter wavelengths. Moreover the I482nm/I545nm luminescence intensity ratio is much higher than in bulk glass.