Stucture And Photorefractive Properties Of Fe: Stoichimetric Lithium Niobium Crystals

Fe:Stoichimetric Lithium Niobate single crystals with varied Fe concentration were grown by the Czochralski method under the assistance of K2CO3 flux, and the as-growth crystals have no macroscopic defects and have a perfect optical homogeneity. The optimum technological conditions for growing Fe:Stoichimetric Lithium Niobate single crystals were determined.The results from the XRD experiment of the crystals showed that the Fe:SLN crystals hold the same lattice structure as pure SLN crystals, but the lattice constants of the Fe:SLN crystals had varied slightly, and the unit cell volume increased as Fe concentration increased. Through investigating the UV-Vis absorption spectra and IR absorption spectra, the occupying mechanism of the doped ion were studied.Using two beam coupling experiment, the dependence of the diffraction efficiency and the response time of the Fe doped SLN was studied systematically. The results indicated that the holographic storage properties of the Fe:SLN crystals were affected by the Fe concentration and the treating state of crystals. Fe which acted as the photorefraction ion can improve the diffraction efficiency of Fe:SLN crystal, and the writing time decreased as the Fe concentration increased. The writing time was shorter at the reduction state and the erasing time was longer at the oxidation state.The diffraction efficiency of the Fe:SLN single crystals was not only affacted by the doped Fe concentration, but also by the write-in light intensity.The transmission facula is directly observed to study the optical damage resistance of the Fe:SLN crystals. The dependence of the optical damage resistance of the co-doped Fe:SLN crystals on the Fe concentration was studied systematically. The results showed that, due to the defects concentration of Stoichimetric Lithium Niobate and the photorefraction sensitivity impurity's concentration were all very low, it was not easy to happen the optical damage. The optical damage resistance of Fe:SLN crystals decreased as the Fe concentration increased. And it showed that the optical damage resistance of Fe:SLN was stronger than that of Fe:CLN.