Radiative parameters of Nd3+-doped titanium and tungsten modified tellurite glasses for 1.06 µm laser materials

Abstract

Different glass matrices doped with Nd3+ have been prepared by the conventional melt quenching method with the molar compositions of (89−x)TeO2–10TiO2–1Nd2O3–xWO3 (x=0, 10 and 20mol%). The XRD, FTIR, absorption spectra, photoluminescence (PL) spectra and luminescence decay curves of glass samples were measured at room temperature and investigated, respectively. The XRD pattern confirms the amorphous nature of the prepared glasses. The free OH− content in the 1.0mol% Nd2O3-doped glass samples has been estimated from their measured Infrared transmittance spectra. Judd–Ofelt (J–O) intensity parameters were derived from the absorption spectrum and used in turn to estimate radiative properties such as radiative transition probabilities (AT), radiative lifetimes (τr) and branching ratios (βJJ′) for 4F3/2→4I9/2, 11/2, 13/2 transitions. From the emission spectra, peak wavelength, effective bandwidth (Δλeff) and stimulated emission cross-section (σemis) were calculated for the 4F3/2→4I11/2 transition. The values of the stimulated emission cross-section obtained in the present Nd3+-doped tellurite glasses are on the higher side than the values of the reported as well as commercial. The luminescence decay curves for the 4F3/2→4I11/2 transition have been measured to evaluate the quantum efficiency (η). The results show a significant increase of the quantum efficiency (η) with the increases of WO3 concentration. Notably, it is found that the quantum efficiency in the TTNW20 glass is much longer than that in most other glasses which indicates that this glass system could be considered as a good candidate for near-infrared lasers at 1.06μm.