Upconversion luminescence in Yb3+-doped yttrium aluminum garnets

Abstract: In this paper, we present results on upconversion luminescence performed on Yb3+-doped yttrium aluminum garnets under 940nm excitation. The upconversion luminescence was ascribed to Yb3+ cooperative luminescence and the presence of rare earth impurity ions. The cooperative luminescence spectra as a function of Yb concentration were measured and the emission intensity variation with Yb concentration was discussed. Yb3+ energy migration quenched the cooperative luminescence of Yb:YAG crystals with doping level over 15at%. [Copyright &y& Elsevier]