When a visible laser beam passes through β-BaB<sub>2</sub>O<sub>4</sub> (BBO), scattered light can be observed along the beam within the crystal. Scattering centers caused by structural defects in Czochralski-grown BBO can be reduced by 95% by annealing at 920 °C. In the flux-grown BBO, centers actually increase by the same annealing because the process causes microcracks and/or secondary inclusions. It is shown that annealed Czochralski-grown BBO is superior to flux-grown BBO (annealed or as-grown) in terms of optical loss.
© 1999 Optical Society of America
Hikaru Kouta and Yasuhiko Kuwano, "Annealing to Reduce Scattering Centers in Czochralski-Grown β-BaB2O4," Appl. Opt. 38, 1053-1057 (1999)