Optical properties of lead-free oxyfluoride germanate glasses doped with Pr3+

Optical properties of Pr3+ ions in lead-free germanate glasses modified by BaF2 were investigated. Luminescence bands related to P-3(0) -> H-3(4), P-3(0) -> H-3(5), D-1(2) -> H-3(4), P-3(0) -> H-3(6), P-3(0) -> F-3(2) transitions of Pr3+ were registered under 450 nm excitation. The relative integrated luminescence intensities of P-3(0) -> H-3(4) transition (blue) to the P-3(0) -> F-3(2) transition (red) of Pr3+ ions strongly depend on fluoride modifier BaF2 in glass composition. The blue-to-red luminescence intensity ratios of Pr3+ are drastically reduced, when BaO is partially substituted by BaF2. The luminescence lines due to P-3(0) -> F-3(2) hypersensitive transition of Pr3+ are blue shifted with increasing BaF2 concentration.