FLUORESCENCE MECHANISMS OF Tm~3+ - AND Yb~3+/Tm~3+ DOPED AlF3-BASED FLUORIDE GLASS

摘要

A complete set of spectroscopic parameters, including Judd-Ofelt parameters, radiative transition probabilities, radiative lifetime, branching ratios and integrated absorption cross section, have been calculated for Tm~3+ - doped fluoroaluminate (AYF) glass, based on the measured absorption spectra. The mechanism of Tm~3+ →Tm~3+ and Yb~3+ <＝>Tm~3+ energy transfers and fluorescence properties have been investigated in both Tm~3+ single-doped and Yb~3+/Tm~3+ double-doped AYF glasses. The cross-relaxation process) ~3F_4 +~3H_6→2~3H_4, is proved, which makes the optimum Tm~3+ concentration of 1.77μm nuorescence (~3H_4→~3H_6) much higher than 1.45μm nuorescence (~3F_4→~3H_4) in Tm~3+ : AYF glasses. In Yb~3+/Tm~3+ : AYF glasses, a stronger concentration quenching is found for the 476nm emission than that for the 797nm emission, and is discussed under the 970nm-excitation.