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The shielding and spectroscopic properties of Pr + 3 and Pr3+/Ho3+-codoped tellurite glass were investigated. The intensity parameters (Ω2 = 3.24-, Ω4 = 1.64-, Ω6 = 1.10 × 10−20 cm2) as well as the radiative lifetimes of 3F4 + 5S2 and 5I6 excited states of Ho3+ ions were equal to 301 μs and 3.0 μs, respectively. The former value appears to be much higher than that obtained from the lifetime measurement, indicating the presence of various energy transfer processes. The NIR spectrum of Pr3+/Ho3+-co-doped tellurite glass is dominated by strong Ho3+: 5I6 emission at around 1200 nm, being the result of the energy transfer from Pr3+ to Ho3+ ions. The shielding effectiveness of the prepared glasses showed good performance against high-energy photons. These findings suggest that the prepared glasses could be used in laser technology such as photodynamic therapy (PDT) treatment procedures and as shielding for radiation protection. [ABSTRACT FROM AUTHOR]

To increase the emission intensity of Pr SP 3+ sp ions, Yb SP 3+ sp ions appear as an efficient sensitizer [[13]]. Due to a non-exponential character of the decay data, we have determined the experimental lifetime as being equal to the effective lifetime defined as HT ht Graph (4) Graph: Fig. [[36]]) HT ht Graph (5)where I i SB Pr-Yb sb and I i SB Pr sb are the effective lifetimes with and without Yb SP 3+ sp -coping, respectively, but for the same concentration of Pr SP 3+ sp ions. Emission spectra Emission spectra of Ln-doped samples TPr and TPrYb were measured in the same conditions allowing one to compare their relative intensities; additionally, in order to demonstrate the effect of the Pr SP 3+ sp ion concentration ( I N i SB Pr sb ; see Table 1) on the emission spectra, the PL signal of both samples (in arbitrary units) has been divided by I N i SB Pr sb . [Extracted from the article]

We have investigated the spectroscopic properties of Er3+-doped fluorotellurite glasses with the basic molar composition 75%TeO2-10%P2O5-10%ZnO-5%PbF2, modified by replacing 5% TeO2 by a metal oxide, namely WO3 or Nb2O5. The absorption edge of the glasses studied has been described within the Urbach approach, while the absorption and photoluminescence spectra have been analyzed in terms of the standard Judd-Ofelt theory, along with the photoluminescence decay of the 4I13/2 and 4S3/2 levels of the Er3+ ion. The absorption and emission spectra of the 4I15/2 ↔ 4I13/2 infrared transition have been analyzed within the McCumber theory to yield the peak emission cross-section and figure of merit for the amplifier gain. It appears that the fluorotellurite glass containing WO3 as a modifier is characterized by the largest figure of merit, indicating this matrix as a promising new host for doping with Er3+ ions. [ABSTRACT FROM AUTHOR]

We have investigated the spectroscopic properties of Er3+-doped fluorotellurite glasses with the basic molar composition 75%TeO2-10%P2O5-10%ZnO-5%PbF2, modified by replacing 5% TeO2 by a metal oxide, namely WO3 or Nb2O5. The absorption edge of the glasses studied has been described within the Urbach approach, while the absorption and photoluminescence spectra have been analyzed in terms of the standard Judd-Ofelt theory, along with the photoluminescence decay of the 4I13/2 and 4S3/2 levels of the Er3+ ion. The absorption and emission spectra of the 4I15/2 ↔ 4I13/2 infrared transition have been analyzed within the McCumber theory to yield the peak emission cross-section and figure of merit for the amplifier gain. It appears that the fluorotellurite glass containing WO3 as a modifier is characterized by the largest figure of merit, indicating this matrix as a promising new host for doping with Er3+ ions. [ABSTRACT FROM AUTHOR]

We have investigated the optical and spectroscopic properties of new Er 3+ -doped fluorotellurite glasses with the basic molar composition 75%TeO 2 -10%P 2 O 5 -10%ZnO-5%PbF 2 , modified by replacing 5%TeO 2 by four various metal oxides, namely MgO, PbO, SrO and CdO. The ellipsometric data have provided a Sellmeier-type dispersion relation of the refractive index of the investigated glasses. The optical absorption edge has been described within the Urbach approach, while the absorption and fluorescence spectra have been analyzed in terms of the standard Judd–Ofelt theory along with the photoluminescence decay of the 4 I 13/2 and 4 S 3/2 levels of the Er 3+ ion. The absorption and emission spectra of the 4 I 15/2 ↔ 4 I 13/2 infrared transition have been analyzed within the McCumber theory to yield the peak emission cross-section and figure of merit (FOM) for the amplifier gain. It appears that the glass containing MgO as a modifier is characterized by the largest FOM suggesting that the fluorotellurite matrix with this oxide can be a good novel host for Er 3+ ion doping. Finally, we propose a new simple method to calculate the mean transition energy of the McCumber approach as the arithmetic average of the barycenter wavenumbers of absorption and emission spectra. [ABSTRACT FROM AUTHOR]

We have investigated the thermal and spectroscopic properties of Pr 3+ -doped new tellurite matrix with the molar composition 60%TeO 2 –27%WO 3 –10%PbO–3%Lu 2 O 3 (TWPLu). The differential thermal analysis has shown that addition of Lu 2 O 3 to the glass results in an increasing resistance against crystallization. The ellipsometric data have provided a Sellmeier-type dispersion relations of the refractive index of the investigated glasses. The optical absorption edge of the TWPLu matrix has been described within the Urbach approach, while the absorption and fluorescence spectra of the Pr 3+ -doped TWPLu glasses have been analyzed in terms of the standard Judd–Ofelt theory along with the luminescence decay of the 3 P 0 and 1 D 2 levels of the Pr 3+ ion. A significant influence of the Pr 3+ ion concentration on the photoluminescence intensity as well as on decrease of the lifetimes of both levels has been explained by a non-radiative energy transfer between the ions through cross-relaxation and energy migration processes. [ABSTRACT FROM AUTHOR]

Tests on glass texture were made in order to establish the size of porous space in modified glasses Al2O3 from the system Na2O-B2O3-SiO2 after extraction of dissolved boron phase during chemical treatment. A difference was observed in the size and volume of mezo- and micropores in 0.6% and 0.3% Al2O3 glasses depending on temperature of heating. Accounting for the difference of glass structure attempts were made to use them for the selective sorption of hydrocarbons dissolved in water. It follows from the obtained results that differences in hydrocarbon removal are as much as tens of percent. The efficiency of removal is conditioned by the type of glass and grain size of glass applied for sorption. [ABSTRACT FROM AUTHOR]

Abstract: The purpose of this work was to investigate the spectroscopic properties of Pr3+ ions of various concentrations embedded in a new matrix, namely a tellurite–tungstate glass with the molar composition 60%TeO2–27%WO3–10%PbO–3%La2O3 (TWPLa). The optical absorption edge of the TWPLa matrix has been described within the Urbach approach, while the absorption and fluorescence spectra of the Pr3+-doped TWPLa glasses have been analyzed in terms of the standard Judd–Ofelt (J–O) theory along with the luminescence decay of the 3P0 and 1D2 levels of the Pr3+ ion. A significant influence of the Pr3+ ion concentration on the photoluminescence intensity as well as on decrease of the lifetimes of both levels has been explained by a non-radiative energy transfer between the ions through different cross-relaxation channels. The spectroscopic studies have been completed with ellipsometric measurements providing the dispersion relation of the refractive index of the investigated glasses that has been taken into account in the J–O analysis. [Copyright &y& Elsevier]