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Study of Growth and Optical Holographic Storage Properties of Scandium Series Doped Lithium Niobate Crystal

Author: GuiQiang
Tutor: ZhengWei
School: Harbin University of Science and Technology
Course: Materials Science
Keywords: Lithium niobate Crystal growth Photorefractive properties Defect structure Holographic storage
CLC: O734
Type: Master's thesis
Year: 2008
Downloads: 103
Quote: 1
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Abstract


Growth of macro-defect Czochralski method, optical uniformity and good Sc: Fe: the LiNbO 3 crystals and Mg: Sc: of Fe: the LiNbO 3 crystal. Explored the growth of highly doped and a different ratio of lithium niobium-doped lithium niobate crystals suitable process conditions in order to avoid the cracking of the crystal and reduce the segregation of the solute caused by uneven crystal components. Analysis by X-ray powder diffraction results, scandium-based doped lithium niobate crystal in the case of changing the scandium-doped and the Li / Nb ratio, and there is no new phase, but the lattice constant change, indicating that the dopant ions only replace Li of Nb Li / sub> . 4 or the Nb 5 . According to the infrared spectrum of the crystal absorption bands and the UV-visible absorption spectra of the absorption edge with scandium-doped amount, the amount of magnesium-doped Li / Nb ratio changes and the law of mobile analysis to determine the impurities Sc in Sc: Fe: LiNbO 3 < / sub> Crystals and Mg: Sc: Fe: LiNbO 3 Crystals threshold concentration and placeholder. Doped scandium is less than the threshold concentration the Sc 3 ions preferentially replace antisite niobium (Nb Li 4 , occupy of Li < / sup> bit Nb 5 ), and when the amount of doped scandium threshold concentration is reached, all antisite niobium be replaced Sc 3 ions will also enter the normal Li-bit, and niobium bit. With the increase of the Li / Nb, the threshold concentration of the crystals Sc concentration gradually decreases. Same composition Sc: Fe: LiNbO 3 crystals Sc threshold concentration of approximately 3 mol%. In nearly stoichiometric Sc ??of: Fe: the LiNbO 3 crystal the SC threshold value concentration only 0.3mol%. Sc and Mg-doped crystals, Sc and Mg concentration of priority threshold is reached. Moreover Sc in Mg: Sc: Fe: LiNbO 3 the threshold concentration in the crystal than in the non-doped magnesium sc: Fe: the LiNbO 3 crystal lower. In SC, the Mg doping amount of the respective threshold concentration is reached, continue to increase the magnesium ash, Sc, Mg incorporation will reach a common threshold. Photorefractive two-wave coupling and spot distortion method to test the crystal properties and resistance to optical damage performance. The results show that with the doped scandium increase, Sc: Fe: the LiNbO 3 crystal diffraction efficiency and dynamic range decreased, while the recording time and erase time, photorefractive sensitivity increased. Various Li / Nb ratio Sc: Fe: the LiNbO 3 crystals and Mg: Sc: Fe: the LiNbO 3 crystal hem variable performance of its light variation with different scandium Volume of Sc: Fe: LiNbO 3 crystal light hemming varying performance variation is consistent. Threshold is reached in the amount of doped scandium, Sc: Fe: the LiNbO 3 crystal optical damage resistance ability significantly enhanced the ratio Fe: LiNbO 3 crystal is two orders of magnitude higher. Sc: Fe: LiNbO 3 crystal optical damage resistance capacity can be increased by increasing the Li / Nb ratio. For near-stoichiometric Sc: Fe: LiNbO 3 crystal is, when the amount of scandium-doped threshold concentration is reached, and then increase the amount of crystal doped scandium, but lead crystal optical damage resistance ability reduced. Experimental findings may be provided by co-doping of Mg, so that the crystal optical damage resistance ability to further improve on the crystal holographic storage experimental results show that, (5 mol%) Sc: Fe: the LiNbO 3 crystal read image quality is significantly higher than the Fe: the LiNbO 3 crystal and near-stoichiometric ratio (0.1 mol%) Sc: Fe: the LiNbO 3 crystal, indicating that the crystal optical damage resistance The ability to improve the holographic storage process can effectively reduce the noise and improve the quality of the read out image. Doped scandium and to change the crystal in the Li / Nb ratio can effectively improve the defects of the holographic storage, there are conducive to the practical application of the lithium niobate crystal in the holographic storage.

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CLC: > Mathematical sciences and chemical > Crystallography > Crystal physics > The optical properties of the crystal
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