Tm,Ho:Ca(Gd,Lu)AlO4 crystals: Crystal growth, structure refinement and Judd-Ofelt analysis
Zhongben Pan, Pavel Loiko, Sami Slimi, Hualei Yuan, Yicheng Wang, Yongguang Zhao, Patrice Camy, Е. Б. Дунина, А. А. Корниенко, Liudmila Fomicheva, Li Wang, Weidong Chen, Uwe Griebner, Valentin Petrov, Rosa Maria Solé, Francesc Dı́az, Magdalena Aguiló, Xavier Mateos
Abstract
“Mixed” calcium rare-earth aluminate laser host crystals Ca(Gd,Lu)AlO4 (CALGLO) with up to 10.8 at.% Lu codoped with Tm3+ and Ho3+ ions are grown by the Czochralski method along the [001] direction. The segregation of rare-earth ions is studied. The crystal structure is refined by the Rietveld method. Tm,Ho:Ca(Gd,Lu)AlO4 crystallizes in the tetragonal system (sp. gr. I4/mmm) exhibiting a K2NiF4 type structure. The lattice constants are a = 3.6585(6) Å and c = 11.9660(9) Å for a crystal with a composition of CaGd0.8947Lu0.0551Tm0.0448Ho0.0054AlO4. The stability of Ca(Gd,Lu)AlO4 solid-solutions is discussed. The polarized Raman spectra are measured, revealing a most intense mode at 311 cm−1 and a maximum phonon frequency of ∼650 cm−1. The polarized absorption spectra are measured. The transition intensities for the Ho3+ ion are analyzed using the modified Judd-Ofelt theory accounting for configuration interaction.