Phase transition control, melt growth of (Gd,RE)F 3 single crystal and their luminescent properties

Abstract

Rare-earth sesquifluorides with no absorption in visible spectral region, such as LaF 3, GdF 3, LuF 3, YF 3, ScF 3, are the topic of intense study as a host for luminescence materials. However, except Nd:LaF 3, they are not studied as a host for laser materials. The main obstacle troubling further study of GdF 3, LuF 3, YF 3, ScF 3 single crystal is the fact that there is first-order phase transition (LaF 3 type↔beta-YF 3 type for GdF 3, alpha-YF 3 type↔beta-YF 3 type for the rest) between the room and melting temperature.To prevent the phase transition, first of all, we have tried to make solid solution between GdF 3 and YF 3 in such a way that the average cation radii can be shifted to the size that does not have phase transition. Ce 3+ perturbed luminescence was observed in the Ce- and Sr-codoped GdF 3–YF 3 system. Similar solid solution concept was applied to the combination between GdF 3 and YbF 3. The emission spectrum of Yb 3+ that exhibits broad bands around 1 μm was observed. Room temperature up-conversion luminescence spectra of Pr 3+-doped Gd 1− x Yb x F 3 were studied and visible emission from Pr 3+ was obtained under infrared laser pumping in the Yb 3+ broad absorption band at 935.5 nm.