Spectroscopic properties of Yb3+:LuLiF4 crystal grown by the Czochralski method for laser applications and evaluation of quenching processes:: a comparison with Yb3+: YLiF4

Spectroscopic properties of Yb3+ ion in LuLiF4 (LLF) laser host are presented here for the first time. Czochralski technique was used to grow undoped and Yb3+-doped LLF single crystals under CF4 atmosphere. Detailed analysis of Yb3+-doped LLF spectroscopy were made to contribute to the determination of energy levels in this host and a comparison with the isomorphic YLiF4 (YLF) laser host is done. We are dealing with temperature and concentration dependences of both pi and sigma polarizations of the infrared (IR) absorption and emission spectra. Raman spectra were also used to give an attempt for the interpretation of electronic and vibronic levels. Concentration dependence of fluorescence lifetimes allows the measurement of the high radiative lifetime in the range of 2-3 ms and shows a strong self-trapping process. Self-quenching was not seen by the reduction of the decay times but observed by non-radiative up-conversion energy transfer due to the presence of Er3+ and Tm3+ ions as unexpected impurities. Contrary to oxide crystals this process still remains lower than the self-trapping process. Yb3+ pairing and clustering were investigated as well. Evaluation of the laser potentiality of this host by the evaluation of figure-of-merit developed by our group is presented. (C) 2004 Elsevier B.V. All rights reserved.