Energy levels and correlation crystal-field effects inEr3+-doped garnets

The crystal-field energy-level structures of three different ${\mathrm{Er}}^{3+}$-doped garnet systems are analyzed and compared in this study. The garnet hosts are ${\mathrm{Y}}_3$ ${\mathrm{Al}}_5$ ${\mathrm{O}}_{12}$ (YAG), ${\mathrm{Y}}_3$ ${\mathrm{Sc}}_2$ ${\mathrm{Al}}_3$ ${\mathrm{O}}_{12}$ (YSAG) doped with ${\mathrm{Tm}}^{3+}$ as a sensitizer ion, and ${\mathrm{Y}}_3$ ${\mathrm{Sc}}_2$ ${\mathrm{Ga}}_3$ ${\mathrm{O}}_{12}$ (YSGG) doped with ${\mathrm{Cr}}^{3+}$ as a sensitizer ion. The focus is on energy levels assigned to ${\mathrm{Er}}^{3+}$ ions substituted for ${\mathrm{Y}}^{3+}$ at dodecahedral (${\mathit{D}}_2$ symmetry) sites in the cubic garnet lattices. Analyses are carried out on experimental energy-level data that span up to 29 different ${}_{}{}^{2\mathit{S}+1\mathrm{}}{}_{}{}^{}$ ${\mathit{L}}_{\mathit{J}}$ multiplet manifolds (between 0 and 44 000 ${\mathrm{cm}}^{\mathrm{-}1}$) of the ${\mathrm{Er}}^{3+}$ 4${\mathit{f}}^{11}$ electronic configuration. These data include the locations of 117 crystal-field levels of ${\mathrm{Er}}^{3+}$ in YAG, 109 levels of ${\mathrm{Er}}^{3+}$ in YSAG, and 92 levels of ${\mathrm{Er}}^{3+}$ in YSGG.