Optical spectroscopy of Yb3+ centers in BaMgF4 ferroelectric crystal

The following article appeared in Journal of Applied Physics 110.6 (2011): 063102 and may be found at http://scitation.aip.org/content/aip/journal/jap/110/6/10.1063/1.3638040We report on the optical characterization of Yb3+ doped BaMgF4+ nonlinear fluoride crystal grown by the Czochralski technique. Low temperature absorption spectroscopy reveals that Yb3+ incorporates into the matrix at four well differentiated centers. High resolution site selective experiments have been performed to determine the energy level schemes associated with the major Yb3+ centers detected in the system. The fluorescence decay times recorded at 10 K under selective excitation are analyzed for each Yb3+ center. The spectroscopic behavior of the codoped Yb3+:Na+:BaMgF4+ system has been also investigated. Codoping with Na+ eliminates two Yb3+ centers present in the singly doped Yb3+:BaMgF 4+ crystal. The charge compensation mechanisms and site location for Yb3+ in the fluoride matrix are discussedThis work has been supported by Spanish MICINN under Contract Nos. MAT2010-17443 and MAT2009-06580, Comunidad de Madrid under Grant No. PHAMA S2009/MAT-1756 and Universidad Autónoma de Madrid under Contract No. CCG10-UAM/MAT-5290