Search for impurity phases of Nd~3+:YVO_4 crystals for laser and luminescence applications

摘要

Structural investigtion of the Y_2O_3-V_2O_5 system system was undetaken with the aim of characterizing possible segrgated phases appearing during the synthesis of pure and doped yttrim vanadate. Nd~3+:YVO_4 signle crystals obtained by LHPG and flux growth technqiues were studie by high spatial resolution micro-Raman probe (up to 1μm in the X-Y plane) spectroscopy. Thwe confocality of microscope coupled to theRaman microprobe allowed us to select the in-depth resolution of the probe. By mapping several single crystals grown with different methods, a segregated pahse was identified in the flux grown crystal, about 70 μm below the surface. Micro-Raman maps of powder samples prepared by solid state reaction starting from 4Y_2O_30V_2O_5 and 5Y_2O_3-V_2O_5 mixtures gave evidence of this pahse. The spectral features are very similr tothe precipitate found in YVO_4L:Nd~3+ single crystal.