Ir. Martin et al., TIME-RESOLVED FLUORESCENCE LINE NARROWING IN YB3-DOPED FLUOROINDATE GLASSES(), Physical review. B, Condensed matter, 57(6), 1998, pp. 3396-3401
Fluorescence line narrowing measurements have been carried out between
the lowest Stark components of the F-2(5/2)-->F-2(7/2) transition of
Yb3+ ions in fluoroindate glasses. At low concentration (0.15 mol % of
Yb3+) the luminescence spectrum consists in a narrow band which repea
ts the exciting profile, so the migration processes between Yb3+ ions
are not important at this concentration. However, at higher concentrat
ions (0.75 or 2.25 mol %) the luminescence spectrum contains moreover
a broad band produced by other ions nonexcited initially (background f
luorescence). A model is proposed to describe the temporal evolution o
f the narrow band fluorescence and the shape of the background fluores
cence. A very good agreement with the experimental results is found ta
king into account a dipole-quadrupole (S=8) nonradiative energy transf
er process assisted by a phonon.