双掺杂铌酸锂晶体的生长及其光折变性质

Growth and Photorefractive Properties of Bi doped LiNbO 3 Crystals

采用提拉法以固液同成分配比（Ｌｉ２ＣＯ３／Ｎｂ２Ｏ５＝４８．６／５１．４）生长了Ｆｅ掺杂及（Ｚｎ，Ｆｅ）、（Ｍｇ，Ｆｅ）和（Ｃｅ，Ｆｅ）双掺杂ＬｉＮｂＯ３（ＬＮ）单晶。Ｃｅ∶Ｆｅ∶ＬｉＮｂＯ３晶体的质量，指数增益系数和衍射效率皆高于Ｆｅ∶ＬｉＮｂＯ３晶体。所测得（Ｚｎ，Ｆｅ）∶ＬＮ、（Ｃｅ，Ｆｅ）∶ＬＮ、（Ｍｇ，Ｆｅ）∶ＬＮ和Ｆｅ∶ＬｉＮｂＯ３晶体的抗光致散射能力分别为８．２×１０３，３．２×１０２，８．３×１０２和１．２×１０２Ｗ／ｃｍ３；在４８８ｎｍ光进行的光折变实验中还原处理后的（Ｃｅ，Ｆｅ）∶ＬｉＮｂＯ３晶体具有最高的二波耦合增益系数，为４０．２ｃｍ－１，其全息衍射效率可达８２．２％；实验结果表明（Ｚｎ，Ｆｅ）∶ＬｉＮｂＯ３和（Ｍｇ，Ｆｅ）∶ＬｉＮｂＯ３具有抗光散射能力强，响应时间短的特点，而（Ｃｅ，Ｆｅ）∶ＬｉＮｂＯ３的增益系数和衍射效率均为最高，明显优于Ｆｅ∶ＬｉＮｂＯ３晶体。

Using Czochralski method,Fe doped and(Zn,Fe),(Mg,Fe),(Ce,Fe) bi doped lithium niobate crystals were grown with the congruent melt ratio Li 2CO 3/Nb 2O 5=48. 6/51.4.The quality,exponential gain coefficient and diffraction efficiency of Ce∶Fe∶LiNbO 3 are superior to that of Fe∶LiNbO 3.The light scattering ability resistances of (Zn,Fe)、 (Mg,Fe)、(Ce,Fe)and Fe doped LiNbO 3 are 8.2×10 3,3.2×10 2,8.3×10 2 and 1.2×10 2W/cm 3 respectively.Photorefractive measurements showed that the gain coefficent of heavily reduced Ce,Fe∶LiNbO 3 reached to Γ =40.2cm -1 and a holographic efficiency η=82.2%. It is shown that Zn,Fe∶LiNbO 3 and Mg,Fe∶LiNbO 3 have the properties high light scattering resistance and quickly response.And Ce,Fe∶LiNbO 3 has the highest gain and efficiency among those crystals investigated.