Intense blue up-conversion emission in Tm3 +/Yb3 + co-doped phosphate glass

Tm3 +/Yb3 + co-doped phosphate glasses with different concentrations of Tm3 + were prepared by high-temperature melting method. The up-conversion (UC) emission spectra of the samples were measured under 975 nm excitation. The blue UC emission at 477 nm in the sample doped with 0.5 mol% Tm3 + is very strong. By analyzing the power spectra and population processes of the UC emission, we found that photon avalanche phenomenon has existed in the energy transition between Tm3 + and Yb3 + ions, which results in the strong blue UC emission at 477 nm. By this way, the luminous efficiency of the materials doped with Tm3 + will be greatly improved. Our research will be helpful in developing UC emission materials.