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A study on the photorefractive effect in relaxor ferroelectric crystals

弛豫铁电晶体光折变效应的研究

基本信息

批准号：
14350030
负责人：
SHIMURA Tsutomu
金额：
$ 8.83万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

项目摘要

1.Crystal growth and sample preparation(a)We have grown relaxor ferroelectric crystals, 0.91Pb(Zn_<1/3>Nb_<2/3>)O_3-0.09PbTiO_3. (b)The crystals are cut, polished, and poled. The photorefractive effect is observed in Pb based relaxor ferroelectric crystals at the first time. (c)Same crystals, doped with Fe, Mn, and Rh were grown with various concentrations, and their photorefractive properties were evaluated. (d)Light scattering in these crystals were dramatically reduced by [110]. It is also our original finding in this project.2.Evaluation of the photorefractive properties(a)Electro-optic coefficient was measured as 200 pm/V for all the samples. (b)Photorefractive response speed and the two-wave mixing gain were measured for undoped and doped crystals. The maximum two-wave mixing gain was 20cm^<-1>, which was one of the largest value in the bulk ferroelectric crystals. (c)Through the ICP measurement of undoped crystals, no impurities are detected. Some defect levels supposed to acting as photorefractive centers from this result. (d)From the direction of the energy transfer in two-wave mixing and the sign of the electro-optic coefficient, the main carrier was determined to be the holes. (e)Photorefractive effects were enhanced by Fe and Rh doping. Two beam coupling gain was doubled. (f)Photochromisms were observed in Fe doped and Rh doped crystals. This suggest that the feasibility of the non-volatile holographic recording with two color writing method. (g)Photorefractive effects were enhanced in the wavelength range larger than 600 nm in Rh doped crystals. (h)The bulk photovoltaic effect are detected and the enhancement of the diffraction efficiency was observed when the crystal was electrically closed.

1.（a）生长了弛豫铁电晶体0.91Pb（Zn_（1/3）Nb_（2/3））O_3-0.09PbTiO_3。（B）切割、抛光和极化晶体。首次在铅基弛豫铁电晶体中观察到光折变效应。（c）以不同浓度生长掺杂有Fe、Mn和Rh的相同晶体，并评估它们的光折变性质。（d）这些晶体中的光散射被[110]显著降低。2.光折变性能的评价（a）所有样品的电光系数均为200 pm/V。（B）测量了未掺杂和掺杂晶体的光折变响应速度和二波混频增益。最大二波混频增益为20 cm ~ 2<-1>，是体铁电晶体中最大的值之一。（c）通过未掺杂晶体的ICP测量，未检测到杂质。由此推测，某些缺陷能级可能是光折变中心。（d）从二波混频中能量传递的方向和电光系数的符号确定了主要载流子为空穴。（e）Fe和Rh掺杂增强了光折变效应。双光束耦合增益提高一倍。（f）在Fe掺杂和Rh掺杂的晶体中观察到光致变色。这表明了双色写入法非挥发性全息记录的可行性。（g）在大于600 nm的波长范围内，Rh掺杂晶体的光折变效应增强。（h）当晶体被电闭合时，检测到体光伏效应并且观察到衍射效率的增强。