The congruent Zr:Ce:Fe:LiNbO3 crystals have been grown by the Czochralski method with fixed concentrations of CeO2 and Fe2O3 and various concentrations of ZrO2. The Ultraviolet(UV)-Visible(Vis) absorption spectra were measured in order to investigate their defect structures and their optical damage resistance was characterized by the transmission light spot distortion method. The results show that the optical damage resistance of the Zr:Ce:Fe:LiNbO3 crystals improves with the doping concentration of ZrO2 increasing. The dependence of the optical damage resistance on the defect structure of Zr:Ce:Fe:LiNbO3 crystals was discussed.
A series of Zr(1 mol%):Cu(0.1 mol%):Fe(0.03wt%)LiNbO3 single crystals with various Li/Nb ratios having compositions varying between 48.6 and 58 mol% Li2O in the melt were grown by the Czochralski method in the air. The OH− transmittance spectra was investigated to characterize the structure defects of these crystals. The OH− absorption peaks shift to longer wavelength as the [Li]/[Nb] ratio increases and an obvious absorption peak at 3468 cm-1 was observed at the Li/Nb ratio of 1.05. The photorefractive properties of the crystals were experimentally studied using the two-wave coupling method. The results show that as the [Li]/[Nb] ratio increases, the holographic response time and the diffraction efficiency increase under the Li/Nb ratio of 1.2.