Growth and characterization of Yb³⁺-doped YAlO₃ fiber single crystals grown by the modified micro-pulling-down method

The Yb³⁺-doped YAlO₃ fiber single crystals were grown by the modified micro-pulling-down method with the radiofrequency system. The starting melt compositions of (Y_1-xYb_x)AlO₃ were varied as x=0.05, 0.1 and 0.2. The best Yb³⁺-doped YAlO₃ fiber single crystals were obtained for pulling-down rate equal to 0.12mm/min. The grown fiber crystals were transparent and nearly colorless. The purpose of this study was to reveal the conditions of twin and inclusion-free growth of the Yb³⁺-doped YAlO₃ single crystals. To investigate the homogeneity of the grown crystals, distribution coefficient of the Y and Yb ions was measured. The transmission, photo- and radioluminescence features of Yb³⁺-doped YAlO₃ crystal were also investigated in this study. Due to very fast charge transfer luminescence of Yb³⁺ in near-UV-visible spectral range and higher density of Yb-rich YAlO₃, such material is promising candidate for fast scintillators.