Bi_（12）TiO_（20）晶体的全息性能

Holographic Properties of Bi_(12)TiO_(20) Crystal

Ｂｉ（１２）ＴｉＯ（２０）晶体是一种优良的全息记录材料．本论文对纯Ｂｉ（１２）ＴｉＯ（２０）和掺Ｃｅ：Ｂｉ（１２）ＴｉＯ（２０）晶体的衍射效率、半波电压、旋光度等性能进行了测试，并讨论了掺入的Ｃｅ对晶体性能的影响，Ｃｅ（４＋）离子在晶体中取代Ｂｉ（３＋）离子形成新的区域中心．此外还探讨了Ｔｉ原子对晶体族光度的影响，认为Ｂｉ（１２）Ｔｉ（２０）晶体族光度远小于Ｂｉ（１２）ＳｉＯ（２０）、Ｂｉ（１２）ＧｅＯ（２０）的根本原因在于Ｔｉ原子的性质和极化不同于Ｓｉ、Ｇｅ原子．

Bi(12)TiO(20) is a kind of high quality material for holographic record. In this paper, the diffraction coefficiency, half-wave voltages and optical activities of qure-Bi(12)TiO(20)and Ce:Bi(12)TiO(20) have been measured. It is discussed that low content Ce doped in crystal influences its properties, and it is considered that Ce(4+) ions in crystals take the place of Bi(3+) ions to form new local centres. In addition, the influence of Ti on crystal's optical activity has been researched. The reason that the optical activity of Bi(12)TiO(20)is much less than that of Bi(12)SiO(20), Bi(12)GeO(20) lies in the properties and the polarization of Ti atom being very different from St, Ge.