Spectroscopic properties of Er3+-doped and Er3+/Yb3+-codoped PbF2-MOx (MÂ =Â Te, Ge, B) oxyfluoride glasses

A series of Er3+-doped and Er3+/Yb3+-codoped lead germanate (GP), lead tellurite (TP) and lead borate (BP) transparent oxyfluoride glasses were synthesized. Spectroscopic characteristics of these materials were systemically measured. The Judd-Ofelt parameters were calculated according to absorption spectra. F− ions have a strong effect on refractive index (n) and phonon energy of the host. Intense red and green upconversion is closely related to phonon energy, J-O parameters and sensitizer. The GPEY-2 glass (53GeO2-43PbF2-0.5Er2O3-2Yb2O3) shows good transparency and fairly strong upconversion emissions.