Polarized laser excitation, electron paramagnetic resonance, and crystal-field analyses ofSm3+-dopedLiYF

Using both optical absorption and laser-excited fluorescence, we have determined 55 crystal-field energy levels of the ${\mathrm{Sm}}^{3+}$ center in ${\mathrm{LiYF}}_{4}{:\mathrm{S}\mathrm{m}}^{3+}.$ Electron paramagnetic resonance determines the symmetry of the center to be tetragonal, with effective spin Hamiltonian parameters of ${g}_{\ensuremath{\parallel}}=0.410\ifmmode\pm\else\textpm\fi{}0.005$ and ${g}_{\ensuremath{\perp}}=0.644\ifmmode\pm\else\textpm\fi{}0.002.$ Inclusion of hyperfine interactions yields magnetic hyperfine constants of ${A}_{\ensuremath{\parallel}}=205\ifmmode\pm\else\textpm\fi{}5\mathrm{MHz}$ and ${A}_{\ensuremath{\perp}}=735\ifmmode\pm\else\textpm\fi{}5\mathrm{MHz}$ for the ${}^{147}\mathrm{Sm}$ isotope and ${A}_{\ensuremath{\parallel}}=165\ifmmode\pm\else\textpm\fi{}5\mathrm{MHz}$ and ${A}_{\ensuremath{\perp}}=605\ifmmode\pm\else\textpm\fi{}5\mathrm{MHz}$ for the ${}^{149}\mathrm{Sm}$ isotope. Truncating the ${4f}^{5}$ configuration to the lowest 30 multiplets, ${D}_{2d}$ symmetry crystal-field fits to the experimental energy levels yield physically reasonable crystal-field parameters with standard deviations under 11 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$. Simultaneous diagonalization of the crystal- and magnetic-field perturbation matrices give calculated magnetic splitting factors in good agreement with the measured ground-state g factors.