Spectroscopy of Yb3+ ions in multisite MgMoO4 crystal

Identifier:  imarina:9452184

Handle: https://hdl.handle.net/20.500.11797/imarina9452184

Authors:  Elabedine, Ghassen Zin; Didenko, Yana S; Subbotin, Kirill A; Titov, Anatolii I; Iskhakova, Liudmila D; Lis, Denis A; Pavlov, Sergei K; Zimina, Yulia I; Kuleshova, Kristina V; Sole, Rosa Maria; Aguilo, Magdalena; Diaz, Francesc; Camy, Patrice; Mateos, Xavier

Abstract:
Yb3+-doped magnesium monomolybdate crystal (Yb:MgMoO4) is grown by the Czochralski method. The crystal structure, thermal expansion, vibronic properties, polarized room- and low-temperature spectroscopy of this new compound were studied. According to the Rietveld refinement, Yb:MgMoO4 belongs to the monoclinic class (sp. gr. C2/m, lattice constants: a = 10.276(9)& Aring;, b = 9.289(6)& Aring;, c = 7.027(6)& Aring; and beta = 106.903(8)degrees). The highest-energy Raman mode of Yb:MgMoO4 is found at 969 cm(-1) and assigned to symmetric stretching vibrations of [MoO4](2-) tetrahedra. Yb3+ ions in MgMoO4 exhibit intense and broad absorption at 978 nm, relatively broad and smooth emission bands above 1 mu m (stimulated-emission cross-section: sigma(SE) = 0.76 x 10(-20) cm(2) at 1031 nm for light polarization E || c) and a long luminescence lifetime (0.63 ms). The low-temperature (12 K) spectroscopic studies evidenced a multi-site behavior for Yb3+ ions in MgMoO4 revealing at least 8 non-equivalent optical centers which are assigned to different charge compensation mechanisms. This induces a strong inhomogeneous spectral line broadening. For envisioned laser applications, the problem of low Yb3+ segregation coefficient (K-Yb similar to 0.029) needs to be solved.