关键词: rare earth scandate, crystal field, photoluminescence, laser crystal

Abstract: A good quality (5 at.% Yb:GdScO$_{3}$) single crystal of $\varPhi30 {\rm mm}\times 37$ mm was grown successfully by the Czochralski method. Its structure is studied by the x-ray diffraction (XRD), and its atomic coordinates are obtained by Rietveld refinement. The crystal field energy level splitting of Yb$^{3+}$ in GdScO$_{3}$ is determined by employing the absorption and photoluminescence spectra at 8 K. Only $^{2}$F$_{7/2}$(4) is far from the ground state $^{2}$F$_{7/2}$(1) by 710 cm$^{-1}$ among the crystal field energy levels split from $^{2}$F$_{7/2}$, so it is more easier to realize the laser operation of $^{2}$F$_{5/2}$(1)$\to^{2}$F$_{7/2}$(4) with wavelength 1060 nm. The spin-orbit coupling parameters and intrinsic crystal field parameters (CFPs). The intrinsic crystal field parameters $\bar{B}_{k}$ ($k=2$, 4, 6) of the crystal were fitted by the superposition model. The CFPs evaluated with $\bar{B}_{k}$ and coordination factor are taken as the initial parameters to fit the crystal field energy levels of the crystal, and the crystal field parameters ${B}^{k}_{q}$ are obtained finally with the root-mean-square deviation 9 cm$^{-1}$. It is suggested that the ligand point charge, covalency and overlap interaction are slightly weaker than charge interpenetration and coulomb exchange interaction for Yb$^{3+}$ in GdScO$_{3}$. The obtained Hamiltonian parameters can be used to calculate crystal field energy levels and wave functions of Yb:GdScO$_{3}$ to analyze the mechanism of the luminescence or laser.

Key words: rare earth scandate, crystal field, photoluminescence, laser crystal