Optical and luminescence properties of Sm2O3 doped SrO–PbO–ZnO–P2O5–TeO2 glasses for visible laser applications

The spectroscopic and structural characteristics of various concentrations of Sm2O3 doped strontium lead zinc phospho-tellurite glasses with molar composition x% Sm2O3 + 5SrO + (15-x) PbO + 20 ZnO + 50 P2O5 + 10 TeO2 (where x = 0.25, 0.5, 0.75, 1 mol%) have been reported here. The XRD and FTIR measurements are performed to explore the structural characteristics of the glasses. The absorption spectra reveal that the bands at 400 nm and 1220 nm are highly intense in comparison to others. The Judd-Ofelt intensity parameters Ωλ (λ = 2, 4, 6) have been evaluated from the absorption and thereby the radiative and lasing parameters are estimated. The most intense excitation band around 400 nm is opted as the excitation wavelength to study luminescence properties. Luminescence spectra exhibit the most intense emission band at 598 nm pertaining to 4G5/2 → 6H7/2 transition which is responsible for reddish-orange colour origination. We have measured the experimental lifetime of the 4G5/2 excited state by the suitable fittings of the decay curves. Luminescence concentration quenching (x > 0.75%) and the reduction of decay lifetimes have been observed owing to enhancement of non-radiative energy losses through the cross-relaxation channels. The higher values of quantum efficiency and stimulated emission cross-section promote the lasing action of the present glasses. The location of CIE chromaticity coordinates recommends that these glasses could be utilized as reddish-orange color emitting laser materials.