Spectroscopic and structural properties of YbF3-doped fluorophosphate glasses

Compositional influences on the spectroscopic properties of Yb3+ and the structural variations with the introduction of YbF3 were studied in fluorophosphate glasses. Emission cross-section (σemi) and gain coefficient (σemi × τf) were calculated which exhibit maximum at RF2 = 33 mol%. YbF3 has an important effect on the glass forming ability of fluorophosphate glasses when RF2 is over 36 mol%. The study of Raman spectra showed big differences on the glass structure between non-Yb3+ and Yb3+-doped glasses. The main building units in Yb3+-doped samples are metaphosphate groups, pyrophosphate groups (P2(O,F)7, PO3F), Al[F6] + Al[O,F]6 and F3Alsingle bondOsingle bondAlF3 while those of the non-Yb3+-doped glasses are monophosphate group P(O,F)4, little pyrophosphate group, Al[F4] + Al[F6] + Al[O,F]4 + Al[O,F]6 and F3Alsingle bondOsingle bondAlF3, which means Yb3+ ions contribute to a better glass polymerization and network uniformity.