OPTICAL SHG EFFECT OF STOICHIOMETRIC Ba4Na2Nb10O30 (BNN), Gd-DOPED BNN, AND Nd-DOPED BNN

In order to investigate the doping effect of Ba2NaNb5O15 by rare-earth ions, single crystals of stoichiometric BNN, Gd-doped BNN, and Nd-doped BNN were synthesized. The measurements were carried out for second harmonic generation (SHG), microscopic observation on {001}, and for dielectric property of these materials. The considerable effects by the doping were found for the SHG. The doping effect was investigated from the point of view of the theory of electro-optical and nonlinear optical effect on oxygen octahedral ferroelectrics, and from that of domain structure. Microscopic observation proved that the refractive index fluctuation causes several SHG phase matching conditions.