| 摘要 |
PURPOSE:To produce a high quality lithium niobate single crystal free from cracks and spiral curve and having low sub-grain density in a high yield. CONSTITUTION:When a lithium niobate single crystal contg. at least Li, Nb and O is grown by a melting and solidifying method, growth is carried out in an atmosphere of a neutral gas such as N2, He or Ar, a reducing gas such as H, or CO or a neutral gas mixed with H2, CO, etc. When Mg or Zn is added besides the above three elements, the additive is uniformly dispersed in the resulting entire crystal and the objective high quality lithium niobate single crystal having high resistance to damage by light can be grown. The FZ method or the EFG method as well as the Cz method can be adopted as the melting and solidifying method. The Cz method is excellent from the viewpoint of the control of crystal quality and the increase in diameter. This single crystal is used as the optical material of a waveguide type optical device, an SHG element, etc. |
