Optical and gain properties of series of crystals LiF-YF3-LuF3 doped with Ce3+ and Yb3+ ions

Here, we present first results of systematic studies of host cation variation impact on spectral-kinetic, photochemical and gain properties of Ce3+-doped LiYF4 (YLF), LiLuF4 (LLF) and LiY1−xLuxF4 family crystals. 5d-4f luminescence decay of Ce3+ ions studies, together with pump-probe experiments, indicate that previously reported twice higher luminescence quantum yield in LLF compared with that of YLF crystals is provided by more efficient upper lasing level feeding due to recombination and higher color center destruction rate in LLF against YLF crystals. Namely, it is responsible for higher energetic characteristics of laser based on Ce3+:LLF crystals. Strong and wide pump-induced absorption band centered at 310 nm is observed in Ce3+:YLF. This band is shifted to blue and its intensity goes down with Lu content. We have evaluated free charges recombination rate, excited state absorption cross-section for Ce3+ ions and some other photodynamic processes related microparameters. Fitting results indicate that pump-induced color centers lifetime decreases with Lu-content in LiYF4-LiLuF4 mixture and it can be associated with more efficient color center bleaching by Ce3+ ions 5d-4f fluorescence.