Growth, optical properties and defects of Tb:YAl_3(BO_3)_4 crystal

摘要

Single crystal of terbium-doped yttrium aluminum tetraborate Tb:YAl_3(BO_3)_4 (Tb:YAB) has been grown by the flux method. X-ray powder diffraction (XRPD) was used to check the lattice structure of the Tb:YAl_3(BO_3)_4 crystal. The unit-cell parameters calculated by the TEROR program are a=b=9.3098 A, c=7.2547 A and V=542.53 A~3. The transmittance and fluorescence spectrums of Tb~(3+):YAl_3(BO_3)_4 crystal are measured at room temperature. The position of cutoff edge is at 225 nm. Four emission transitions located at 485, 542, 590 and 622 nm are observed. The green emission transition (~5D_4 -> ~7F_5) at 542 nm is more intense than other transitions. The defects in Tb:YAB crystal were investigated by transmission electron microscopy (TEM). Cracks and inclusions are main defects in Tb:YAB crystal.