Down-/Up-conversion luminescence behaviors and energy transfer analysis in Tm3+ and Tm3+/Yb3+ co-doped tellurite glasses

Glasses with the chemical composition of (50-x-y) TeO2-30ZnO-10YF3-10NaF-0.5Tm2O3-yYb2O3 (y = 0.5, 1.0, and 3.0 mol%) are developed using a melt-quenching method. Measurements of absorption, excitation, down and up-conversion emission spectra, and decay times were used to investigate the energy transfer processes. Cross-relaxation mechanisms caused the emission intensity to decrease at higher Tm3+ ion concentrations. The Tm3+/Yb3+ co-doped glasses showed strong up-conversion emission under the diode laser excitation at 978 nm. Studies on the dependence of pump energy revealed the mechanism underlying the up-conversion luminescence. According to the findings, the developed Tm3+/Yb3+co-doped glasses are also found to be a promising option for spectral conversion and emission (visible and near infrared) applications.