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A group of highly Er3+-doped TeO 2 –BaF 2 –LaF 3 –La 2 O 3 fluorotellurite glasses was prepared by high-temperature melting and rapid cooling. The Judd-Ofelt (J-O) theory intensity parameters, radiative transition rate, and radiative lifetime of Er3+ ions were calculated based on the absorption spectra. The luminecence spectra at 2.7 μm and luminescence lifetime curves of Er3+ ions in fluorotellurite glasses, excited at 980 nm, were studied. The fluorotellurite glass exhibits high infrared transmittance (88 %), excellent thermal stability (ΔT > 105 °C), and low phonon energy (781 cm-1). According to Fuchbauer-Ladenburg theory, the absorption and emission cross sections of Er3+-doped fluorotellurite glass at 2.7 μm are 5.50×10−21 and 6.28×10−21cm2, respectively. These findings suggest that the glass holds significant potential for applications in mid-infrared (MIR) fiber lasers. • The fluorotellurite glass possesses high infrared transmittance (88 %). • The prepared glass exhibits excellent thermal stability (ΔT > 105 °C). • The prepared glass has low phonon energy (781 cm-1). • The fluorotellurite glass exhibits strong luminescence at 2.7 μm. [ABSTRACT FROM AUTHOR]

Herein, zinc sodium borate glasses containing samarium ions were fabricated using the traditional melt-quenching approach and explored using several spectroscopic and structural methods. The XRD data corroborated the host glass specimen's non-crystalline nature. Scanning electron microscopy and the energy dispersive X-ray spectroscopy method were utilized to study the morphological and homogenous attributes. The UV–Vis–NIR wavelengths of absorption showed a total of seventeen distinct Sm3+ ion peaks. The three transitions 4G 5/2 → 6H 9/2 , 6H 7/2 , and 6H 5/2 are evident in the PL data at wavelengths of 644, 597, and 561 nm, respectively, in the red, reddish-orange, and greenish-yellow zones. The luminescence intensity of the investigated glass specimens increases up to 0.4 mol% Sm3+ ion content thereafter reducing because of the non-radiative transfer of energy. The estimated JO intensity parameters exhibit a trend of Ω 2 >Ω 4 >Ω 6. The trend of the assessed radiative parameters also demonstrated that they are sensitive to changes in the glass network. The Futchbauer-Ladenburgh theory was used to compute the emission cross-section of various transitions utilizing the radiative parameters. The 1931 CIE chromaticity coordinates assessments corroborate the reddish-orange luminescence from the fabricated glasses. The outcomes have proven that obtained BNZSm x glasses doped with low concentrations of trivalent samarium ions are well suited for reddish-orange solid-state lighting systems. [Display omitted] • The efficacy of low-concentration Sm3+ ions on spectroscopic features of alkali zinc borate glasses has been studied. • Electronic structure and morphological features were ascertained for the studied glass specimens. • Judd-Ofelt attributes were investigated for 0.4 mol% doped ZnNaB glass. • The results revealed that the 0.4 mol% of Sm3+ doped ZnNaB glasses are beneficial for solid state lighting devices. [ABSTRACT FROM AUTHOR]

We report on a modification of the Judd-Ofelt theory accounting for thermal populations of Stark sub-levels of the multiplets involved in transitions in absorption and emission. The calculations require the data on the crystal-field splitting, the irreducible representations of Stark sub-levels and the selection rules for electric-dipole transitions. Simple formulas for absorption oscillator strengths and probabilities of radiative spontaneous transitions are obtained. The application of the proposed model allowed us to remove the contradiction between the transition intensities in absorption and emission (3H 6 ↔ 3F 4) for Tm3+-doped crystals. It was also used to explain the experimental temperature dependences of luminescence lifetimes of the 3F 4 Tm3+ manifold in two widely used laser crystals, LiYF 4 and Y 3 Al 5 O 12. The case of Yb3+ ions featuring a small number of crystal-field sub-levels is also considered. • Judd-Ofelt theory accounting for thermal populations of Stark sub-levels. • Simple formulas for absorption strengths and radiative transition probabilities. • The contradiction between Tm3+ absorption and emission transition intensities is resolved. • Temperature dependence of luminescence lifetimes of the 3F 4 Tm3+ manifold. • The case of Yb3+ ions featuring a small number of crystal-field sub-levels is considered. [ABSTRACT FROM AUTHOR]