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Several optical applications demand for enhanced optical response of rare earth containing glasses. In the present investigation, modification in spectral features with the dispersion of gold nanoparticles in Dy3+ doped bismuth borosilicate glasses is reported. All the glass samples were prepared using conventional melt-quench technique. Prepared glasses were characterised using Fourier transform infrared spectroscopy (FTIR), dilatometery, field emission scanning electron microscopy (FESEM), Uv–Vis–NIR spectroscopy and photoluminescence. Thermal studies carried out using dilatometer confirms the decrease in glass transition after co-doping of gold nanoparticles and Dy3+. Field emission scanning electron microscopy revealed the existence of gold nanoparticles inside the glassy matrix. A marginal change in the values of Judd-Ofelt parameters of glasses is observed after the incorporation of gold nanoparticles. Significant enhancement in emission intensities is observed after the addition of gold nano-particles. The high stimulated emission cross-section (σ e m i ) and radiative transition probability values for prepared glasses confirms their suitability for the fabrication of yellow light laser. • Stability of gold nanoparticles inside the bismuth borosilicate glass system. • An increase in the Y/B ratio is observed from 4.3:1 to 6.2:1 after gold nanoparticles addition. • Glass for photonic devices. [ABSTRACT FROM AUTHOR]

In the present report, erbium doped zinc borotellurite glasses were irradiated with 50 kGy gamma radiation using a60Co radioisotope source. The effect of gamma irradiation on the physical, structural, optical and spectroscopic properties of erbium doped zinc borotellurite glasses was studied. Also the shielding properties of the un-irradiated glasses were studied with the help of Phy-X/PSD software. The gamma irradiation caused some structural changes as indicated by FTIR and Raman studies which may be due to the formation of the new structural units. Its influence on the optical properties like band gap (direct and indirect band gap), Urbach energy and refractive index were analyzed with the help of UV–Vis–NIR spectrometer. The UV–Vis–NIR absorption spectra showed increase in absorption after the gamma irradiation. The optical band gap value decreased for the irradiated samples. The spectroscopic properties such as stimulated emission cross-section, bandwidth, lifetime etc. Got marginally modified due to gamma irradiation. The shielding properties of the un-irradiated glasses were improved with the increasing rare earth concentration. The glasses with rare earth doping showed less changes in their properties after gamma irradiation which indicates that these glasses are more resistant to gamma radiation as compared to the base glass. [Display omitted] • The Er3+-doped zinc borotellurite glasses were further subjected to 50 kGy gamma ray dose using a60Co radioisotope. • The effect of gamma irradiation on the structure was found to be more dominant in the undoped sample then the doped sample. • The spectroscopic properties of the glasses were slightly modified by the irradiation. • The shielding properties of the glasses were improved after rare earth doping. [ABSTRACT FROM AUTHOR]

• The TBZEr x GC have been obtained by heat treatment of TBZEr x glasses for 4 h at 400 °C. • An increase in the emission intensity and up-conversion intensity is observed after ceramization. • An increase in the lifetime values is observed after ceramization of the glass samples. The effect of heat treatment on spectroscopic and structural properties of Er3+-doped zinc borotellurite glasses (TBZEr x) is studied in the light of absorption, emission, x-ray diffraction and field emission scanning electron microscopy. An increase in thermal stability factor (ΔT) with increasing erbium ion (Er3+) is observed. X-ray diffraction (XRD) confirms the existence of α- TeO 2 and Er 2 (TeO 3) 3 phases in vitreous samples after heat treatment. The band gap and Urbach energy decrease after heat treatment. The Judd-Ofelt parameters indicate high asymmetry in the environs of Er3+ ions. The CIE chromaticity coordinates for prepared samples lies in green region. While going from TBZEr x to TBZEr x GC, an increase in lifetime values is observed for same rare earth (RE) concentration. An increase in the emission intensity and up-conversion intensity is observed after ceramization. The higher spectroscopic properties like stimulated emission cross-section (σ emi (λ)), lifetime (τ) and quantum efficiency (η) values of TBZEr x GC than TBZEr x suggests their suitability for photonic applications. The gain coefficient for transition 4I 13/2 to 4I 15/2 of Er3+ doped TBZEr 2.0 GC Image, graphical abstract. [ABSTRACT FROM AUTHOR]

Spectroscopic, thermal and structural properties of rare earth (RE) doped zinc borotellurite glasses and nano-glass-ceramics are characterized using UV–Vis-NIR spectroscopy, photoluminescence (PL), decay time measurements, differential thermal analysis (DTA), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and Raman spectroscopy. It is found that there is an increase in thermal stability factor with the increase of dysprosium ion (Dy3+) concentration. XRD results confirm the amorphous character of glasses and the presence of α-TeO 2 and γ-TeO 2 phases in nano-glass-ceramics. Raman spectroscopy results show the formation of non-bridging oxygens (NBO's) by the addition of Dy 2 O 3 at the expense of Te-O-Te linkages of TeO 4 units and there is formation of the crystalline phases in the prepared glasses on heat treatment. A considerable change in the values of Judd-Ofelt parameters of glasses is observed after the heat treatment. The CIE Coordinates of TBZDy 0.5 GC (0.32, 0.34) are closer to that for commercial pc-LED (0.32, 0.33). There is a decrease in the lifetime is observed with the increase in concentration of Dy3+ due to concentration quenching. The high stimulated emission cross-section (σ emi), lifetime and quantum efficiency (η) values for prepared glasses and nano-glass-ceramics imply their suitability for the fabrication of white light laser. Unlabelled Image • The nano-glass-ceramics have been obtained by heat treatment of Dy3+ doped zinc borotellurite glasses for 4h at 703K. • Absorption, luminescence and lifetime have been recorded for glasses and nano-glass-ceramics. • Judd-Ofelt parameters follow the trend as Ω 2 > Ω 4 > Ω 6. High Ω 2 values indicate higher asymmetry around the Dy3+ ion site. • The CIE Coordinates of TBZDy 0.5 GC (0.32, 0.34) are closer to that of commercial pc-LED (0.32, 0.33). [ABSTRACT FROM AUTHOR]