Crystallization and photoluminescence properties of α-RE_2(WO_4)_3 (RE: Gd, Eu) in rare-earth tungsten borate glasses

摘要

Glasses with the compositions of 22.5RE_2O_3-47.5WO_3-3OB_2O_3 (mol%) (RE: Gd, Eu) were prepared by a conventional melt quenching method, and α-Gd_2(WO_4)_3 and α-Eu_2(WO_4)_3 crystals were synthesized through their crystallization. The two types of WO_4 tetrahedra present in α-RE_2(WO_4)_3 provide the Raman bands at 931-934 cm~(-1) for W~(II)O_4 tetrahrdra with much distortions and at 946-950 cm~(-1) for W~IO_4 tetrahedra with a near regular symmetry. The crystallized samples containing α-Eu_2(WO_4)_3 exhibit strong red emissions under the excitation at 396 and 467 nm, although the base glass has no photoluminescence emission. α-Gd_2(WO_4)_3 and α-Eu_2(WO_4)_3 crystals were patterned on the glass surface by irradiations of a continuous wave Yb:YVO_4 fiber laser (wavelength: 1080 nm).