[Li]/[Nb]比对Ce:LiNbO_3晶体结构及光折变性能的影响  

Influence of [Li]/[Nb] Ratios on Structure and Photorefractive Properties of Ce:LiNbO_3 Crystals

作　　者：王淼 王锐[1] 杨春晖[1] 徐衍岭[1] 刘欣荣[1] 吕祖舜[1] 

机构地区：[1]哈尔滨工业大学应用化学系,哈尔滨150001

出　　处：《人工晶体学报》2006年第5期1003-1006,共4页Journal of Synthetic Crystals

基　　金：哈尔滨市科技攻关项目(2005AA5CG058)

摘　　要：在铌酸锂(L iNbO3,LN)中掺入摩尔分数为0.1%的CeO2,以提拉法从不同[L i]/[Nb]摩尔比([L i]/[Nb]=0.750,0.850,0.946,1.100)的熔体中生长出了Ce:LN晶体。测试了晶体的晶格常数、红外光谱和居里温度。结果表明:随着[L i]/[Nb]比的增加,晶体仍为三方的LN晶体,且晶格常数和晶胞体积没有发生大的变化,v(OH-)振动峰的位置依次向长波方向移动,居里温度依次增加,结构缺陷减少。由于Ce和[L i]/[Nb]比的协同作用,[L i]/[Nb]比为1.100的Ce:LN晶体已接近化学计量比,[L i]/[Nb]比为0.850的Ce:LN晶体的居里温度近似等于纯LN晶体。利用二波耦合光路测试了晶体的衍射效率、写入时间和擦除时间,计算了晶体的光折变灵敏度及动态范围。测试了晶体的抗光致散射能力,结果表明:[L i]/[Nb]比越高的Ce:LN晶体的光折变性能越好。并分析了不同[L i]/[Nb]比Ce:LN晶体光折变性能增强的机理。Abstract：Ce ：LiNbO3 crystals were grown by Czochralski method from melts with different [ Li ]/[ Nb ] ratios, while the content of CeO2 was 0.1mol%. Crystal lattice constants, IR spectroscopy and Curie temperatures were tested. The results showed that they are remain LN crystals, the crystal lattice constants and crystal volumes do not change too much, the peaks of IR shift to long direction, Curie temperatures are increased and structure defects of crystals are decreased with the increasing of the [ Li]/[ Nb] ratios. Because of cooperation between Ce and [Li]/[Nb] ratios, Ce：LN with [Li]/[Nb] ratios of 1. 100 is approached to stoichiometry and the curie temperature of Ce ： LN with [ Li ] / [ Nb ] ratios of 0. 850 is closed to pure LN. The diffraction efficiency （η）, writing time （τw） and erasure time （τe） were measured with two-beam coupling experiment. The dynamic range （M^#） and the sensitivities （S） were calculated. The ability of resistance to optic damage was tested. The results showed that the higher of [ Li ] / [ Nb ] ratio is, the better of the properties are. The mechanism was also analysed.

关 键 词：Ce:LiNbO 晶体 结构缺陷 [Li]/[Nb]比 光折变性能 

分 类 号：O734[理学—晶体学]