beta-BaB2O4 (BBO) phase-matching-direction growth was carried out by t
he Czochralski (CZ) method. Cylindrical BBO seed crystals, 4 mm in dia
meter and 25 mm in length, were used along the Nd:YAG laser-SHG, THG,
and FHG phase-matching directions (theta = 22.8, 31.1, 47.6 degrees).
The tips of the seeds were tapered to 2.5 mm and etched with phosphori
c acid at 100 degrees C for 2 min. BBO crystals were pulled from a sto
ichiometric BaB2O4 melt. The melt temperature was decreased at a fixed
rate to avoid large temperature fluctuations at the growth interface.
High-quality BBO crystals (15 mm in diameter and 70 mm in length) wer
e grown along each of the phase-matching directions. This growth techn
ique will contribute to the high-production yield of BBO crystals for
nonlinear optical devices.