双掺杂近化学计量比铌酸锂晶体的全息光学特性研究

Optical Properties of Co-doped Stoichiometric Lithium Niobate

在LiNbO3中掺入0.2mol%MnO和0.1mol%Fe2O3,采用顶部籽晶法生长了双掺杂近化学计量比铌酸锂晶体.紫外吸收测试结果表明,晶体成分趋近于化学计量比.采用二波耦合光路测试了晶体的光折变性能.晶体的指数增益系数达到28cm-1,衍射效率为68.3%,响应时间为亚秒级.利用晶体进行了体全息存储实验,实验结果显示,双掺杂近化学计量比晶体的图像存储质量明显好于相同掺杂的同成分晶体,记录速度较同成分晶体提高了二个数量级.

Optical quality near stoichiometric lithium niobate doped with Fe203 and MnO was grown by topseed solution method. The results of UV absorption indicate that the ratio of n（Li）/n（Nb） is close to stoichiometric. The exponential gain coefficient, diffraction efficiency and response time were measured by tow wave coupling light. The results show that the exponential gain coefficient and diffraction efficiency of near stoiehiometric crystal reach to 25 cm ^-1 and 68. 3%, respectively, while response time is less than 1 second. Holographic storage experiment was carried out using the grown crystal. The results indicate that the quality of image storage is much batter than that of congruent crystal with the same dopants, and the recording speed is three times faster than that of congruent crystal.