同成分掺镁铌酸锂晶体紫外光致吸收阈值效应的研究  

Studies on the Threshold Effect of the Ultraviolet-Light-Induced Absorption Change in Congruent LiNbO_3∶Mg

作　　者：付博[1] 张国权[1] 赵璐冰[1] 乔海军[1] 徐庆君[1] 申岩[1] 许京军[1] 孔勇发[2] 孙军 陈绍林[2] 

机构地区：[1]南开大学物理科学学院,天津300071 [2]南开大学泰达应用物理学院,天津300457

出　　处：《光学学报》2005年第11期1531-1534,共4页Acta Optica Sinica

基　　金：教育部优秀青年教师资助计划(2002-350);教育部留学回国人员启动基金(2003-406);教育部新世纪优秀人才支持计划资助课题

摘　　要：研究了同成分掺镁铌酸锂晶体中的紫外光致吸收效应。通过对不同掺Mg浓度铌酸锂晶体的紫外光致吸收系数和双色存储灵敏度的测量,发现同成分掺镁铌酸锂晶体的紫外光致吸收效应具有Mg离子浓度阈值效应。只有当掺Mg摩尔分数大于3.0%时,从近紫外一直延伸到近红外波段的紫外光致吸收效应才显示出来。这一Mg离子浓度阈值效应进一步为双色存储灵敏度的测量结果所证实。该浓度阈值小于掺镁铌酸锂晶体抗光损伤效应的摩尔分数阈值4.6%。这种紫外光致吸收现象可能和掺镁铌酸锂晶体中反位铌NbLi浓度的急剧减少基本消失有关。The ultraviolet-light-induced absorption （UV-LIA） coefficient change is investigated in congruent LiNbO3 crystals doped with Mg^2＋ of different concentrations. By measuring the UV-LIA coefficient change and the two-color recording sensitivity in congruent LiNbO3：Mg, it is found that the UV-LIA coefficient change in congruent LiNbO3：Mg has a threshold effect with respect to the Mg^2＋-doping concentration. It is only when the molar fraction of Mg^2＋ is more than 3.0 % that the UV-LIA change from the near-UV to the near-infrared spectral regions appears. The threshold behaviour is further confirmed by the measurement of the two-color recording sensitivity. This threshold molar fraction is lower than the so-called optical damage-resistant threshold concentration of 4.6% in LiNbO3：Mg, The UV-LIA absorption effect is assumed to be related to the decrease and even elimination of the antisite defect NbLi in LiNbO3 ：Mg.

关 键 词：非线性光学 浓度阈值 紫外 光致吸收 铌酸锂 

分 类 号：O734[理学—晶体学]