Crystallization and photoluminescence properties of α-RE2(WO4)3 (RE: Gd, Eu) in rare-earth tungsten borate glasses

Abstract Glasses with the compositions of 22.5RE 2 O 3 –47.5WO 3 –30B 2 O 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 I O 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).