Local field dependent fluorescence properties of Eu3+ ions in a fluorometaphosphate laser glass

Abstract A fluorometaphosphate laser glass doped with Eu 3+ ions has been synthesized and studied by broad band optical spectroscopy and time-resolved fluorescence line narrowing techniques in order to explore the local field dependent fluorescence properties of the lanthanide ions in this host. From the Raman and the vibronic spectra, various structural phosphate groups coupled to the Eu 3+ ions have been identified. Local field dependent 5 D 0 → 7 F J (J = 0–6) emission spectra and the lifetimes of the 5 D 0 level have been measured under resonant excitation of the Eu 3+ ions at different wavelengths within the 7 F 0 → 5 D 0 band at 16 K. From these data and using the Stark level positions of the 7 F 1 and 7 F 2 multiplets, a crystal-field analysis has been carried out assuming a C 2v orthorhombic local symmetry. The radiative Judd–Ofelt parameters have been calculated for the different local fields found in the glass and their relative variation has been discussed. The results obtained suggest the existence of a relatively narrow distribution of local fields generated by successive distortions of a unique kind of site for all the Eu 3+ ions in this fluorometaphosphate glass.