Zn添加ニオブ酸リチウム結晶の育成と光学特性(<特集>LN,LT結晶の育成と光損傷)

抄録

The properties of Zn doped LiNbO_3, which resits the photorefractive damage, are reviewed mainly from our study. The optically induced change in the birefringence of Zn: LiNbO_3 with 6.6 mol% doping or more can be reduced two orders of magnitude than that in a non-doped crystal. The optical absorption in the ragne of 400-500 nm is reduced and more over the edge is pushed back into the shorter wavelength than non-doped LiNbO_3. These characteristics of Zn: LiNbO_3 resemble to those of Mg: LiNbO_3. The value of birefringence itself and the dependence on the dopant, however, are different from those of Mg: LiNbO_3. The ordinary refractive index is in-creased with Zn content, and the extraordinary one shows nonmonotonic dependence. The change of some physical properties (lattice constant, Curie temperature, extraordinary index, and phase-matching temperature) with a higher concentration of 4.5 mol% of Zn suggests the different siting of Zn in LiNnO_3.