Morphology-dependent resonances of the upconversion emission spectra of the Tm3+/Yb3+ co-doped glass microsphere

In this work, TiBa glass microspheres co-doped with Tm3+/Yb3+ for morphology-dependent resonances of upconversion emission were designed. The components of glass sample were 25TiO2–27BaCO3–8Ba(NO3)2–5ZnO2–8CaCO3–5H3BO3–9SiO2–7water glass–1Tm2O3–5Yb2O3 (wt%). The emission spectra of TiBa bulk glass and the TiBa glass microsphere under 633 nm excitation were measured and discussed. The strong morphology-dependent resonances of up-conversion fluorescence in the microsphere were observed. The observed resonances could be assigned by using the well-known Lorenz–Mie formalism.