Study On Growth And Photorefractive Properties Of Hafnium Cuprum Iron Triple-Doped Lithium Niobate With Various Ratio Of Lithium And Niobium

With the enormous market demand and the advantage of optical volume holographic storage, holographic storage have aroused great concerns. Compared with other holographic storage materials, Li Nb O3 has the advantage of low-cost, technology maturity, easy made large size samples, the biggest photorefractive coefficient and stable properties at room temperatures. But the performance of low diffraction efficiency and low light scattering resistance restrict commercialization of Li Nb O3 as holographic storage material. By increasing the percentage of Li-ion or doping abnormal elements to improve the holographic performance of Li Nb O3. In this article, Hf:Cu:Fe:Li Nb O3 with different [Li]/[Nb] ratios were grown, and the growth processes, defect structures, holographic storage performances were discussed.Firstly, Hf:Cu:Fe:Li Nb O3 with different [Li]/[Nb] ratios(0.946, 1.05, 1.20, 1.38) were grown from high purity powder materials by Czochralski method. The Hf:Cu:Fe:Li Nb O3 with high optical homogeneity and no macroscopic defects were selected to made a group optical sample through Polarization, cutting, grinding, and polishing.Secondly, the optical properties of samples were studied by the IR, UV-absorption spectrum and X-ray crystal powder diffraction. The results of the X-ray crystal powder diffraction showed that the four samples still are all the Li Nb O3 crystals. IR spectrum change tiny indicate that Hf3+ Li and Nb4+Li has the similar ion capacity. The reason of spectroscopic red-shift of UV-absorption spectrum is that Li-ion and Nb-ion were replaced by Hf-ion when [Li]/[Nb] ratio reached 1.38.Finally, through the two-wave coupling experimental, the photorefractive properties of four Hf:Cu:Fe:Li Nb O3 crystal samples were tested. The experiments of optical damage resistance were also performed on those samples. It is conclude that optical response time became short as the increase of [Li]/[Nb] ratios. The diffraction efficiency of [Li]/[Nb] ratios of 1.05 and 1.38 are similar and large than the other samples, and the latter’s dynamic range is larger. The optical damage resistance ability of the two samples are weaker than the sample of [Li]/[Nb] ratio equals 1.20.