On the Iso-Diameter Growth of β -BaB2O4 (BBO) Crystals by Flux Pulling Method

The iso-diameter growth of β-BaB 2 O 4 (BBO) crystals by the flux pulling method have been studied based on the phase equilibrium diagram in the BaB 2 O 4 -Na 2 O pseudo-binary system and from the interface stability. The mathematical expressions for the cooling rate in the growth of the crystals with constant diameter under stable growth conditions are derived, the experimental phenomena such as diameter contraction and difficulty to grow a lengthy crystal by the flux pulling method are explained, the prerequisite for iso-diameter BBO crystal growth from the flux is suggested; a new continuous charging flux pulling method is introduced to grow large-sized high quality crystals with a relative high growth rate.