Optical spectroscopy and visible stimulated emission ofDy3+ions in monoclinicα−KY(WO4)2andα−KGd(WO4)2crystals

Abstract

The complex crystallographic, spectroscopic, and laser properties of ${\mathrm{Dy}}^{3+}$ ions in $\ensuremath{\alpha}\ensuremath{-}\mathrm{KY}({\mathrm{WO}}_{4}{)}_{2}$ and $\ensuremath{\alpha}\ensuremath{-}\mathrm{KGd}({\mathrm{WO}}_{4}{)}_{2}$ single crystals are investigated. Individual Stark levels for many of the ${}^{2S+1}{L}_{J}$ manifolds of ${\mathrm{Dy}}^{3+}$ ${(4f}^{9})$ ions in these monoclinic tungstates are obtained from luminescence and absorption spectra up to \ensuremath{\approx}28 000 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ at \ensuremath{\approx}15 K. A crystal-field splitting analysis for the majority of these manifolds is performed. The rms deviation between 73 experimental and calculated ${\mathrm{Dy}}^{3+}$ Stark levels for both crystals was \ensuremath{\approx}10 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$. Theoretical calculations of intermanifold intensity parameters are carried out by methods using the Judd-Ofelt approach with regard to interconfiguration interaction. All luminescence channels originating from levels of the metstable ${}^{4}{F(3)}_{9/2}$ state are compared with measured data. Pulsed stimulated emission in the visible range at the wavelengths of two lasing channels ${}^{4}{\stackrel{\ensuremath{\rightarrow}}{{F(3)}_{9/2}}}^{6}{H}_{13/2}$ and ${}^{4}{\stackrel{\ensuremath{\rightarrow}}{{F(3)}_{9/2}}}^{6}{H}_{11/2}$ of ${\mathrm{Dy}}^{3+}$ ions are excited and identified. On the basis of observed spectroscopic data we determine the peak cross section for all observed induced transitions as well. We conclude that ${\mathrm{Dy}}^{3+}$-doped monoclinic tungstates $\ensuremath{\alpha}\ensuremath{-}\mathrm{KGd}({\mathrm{WO}}_{4}{)}_{2}$ and $\ensuremath{\alpha}\ensuremath{-}\mathrm{KY}({\mathrm{WO}}_{4}{)}_{2}$ are very attractive crystalline materials for generating visible laser light.