Photo-Induced Carriers in Near-Stoichiometric LiNbO3：Fe Crystal

We detect the photo-induced carriers in near-stoichiometric iron doped LiNbO3 crystal by the holographic technique. The results show that the dominant carriers are electrons in the sample with Li/Nb ratio of 0.9988. By analysis of the OH^- absorption spectra of the crystal, we contribute the electron domination in near-stoichiometric Fe-doped LiNbO3 crystal to the existence of NbLi which provides the anti-site defect to Fe^2＋.     

Transition from Backscattering Speckles to Phase Conjugation in LiNbO3：Fe

We investigate the backscattering for converging beams in iron-doped lithium niobate crystals. Due to the nonlinear properties of the crystal, backscattering exhibits temporally fluctuating speckles that make a transition to the phase conjugate of the incident beam under certain circumstances. Our observation seems to point to a new kind of self-pumped phase conjugation in photorefractive media.     

在LiNbO_3∶Fe晶体中写入与存储圆形和环形波导

在光生伏打、自散焦光折变介质ＬｉＮｂＯ３∶Ｆｅ晶体中写入并存储了圆形与环形波导，并观察到了环形波导之间的相互作用．这种写入波导的方法和技术具有良好的应用前景．     

LiNbO3:Fe晶体二波耦合弱光放大的物理机理

对LiNbO₃: Fe晶体中二波耦合过程进行了动态观测.进一步探讨了LiNbO ₃:Fe晶 体中弱光放大的物理机理.发现LiNbO₃ : Fe晶体中二波耦合过程的弱光放大 对c轴指 向有明显的依赖关系，虽然光生伏打效应对光生载流子的迁移有主要贡献，但扩散机理的贡 献仍不可忽略.弱光最终得到放大是瞬态能量转移与扩散机理引起的能量转移的共同贡献.弱 光放大达到准稳态之后的下降过程为瞬态能量转移的时间指数衰减过程与光散射引起的能量 耗散的共同贡献. 关键词： 光折变效应 光放大 掺杂铌酸锂     

Group Velocity Reduction of Light Pulses in Photorefractive Two-Wave Mixing

We show theoretically that the group velocity of light pulses can be reduced significantly by use of the steep dispersion properties of the phase coupling effect in the photorefractive two-wave mixing process. The group velocity of light pulses of the order of 0.1 m/s can be achieved in typical photorefractive BSO crystals with an appropriate externally applied electric field and moving gratings of appropriate speeds. It is also shown that the slowly propagating light pulses can be set to be amplified after passing through the photorefractive material.     

固体介质中的电磁感应透明效应及其应用

电磁感应透明技术不仅能够改变物质对光场的响应，而且能够调控光场本身的性质．文章介绍了电磁感应透明效应的基本原理，电磁感应透明现象在各种固体介质中的实现，比较了这些固体介质的特性，并讨论了由电磁感应透明现象所产生的各种效应及其应用．     

掺锆铌酸锂系列晶体

本文简介了掺锆铌酸锂系列晶体的研究进展,包括单掺锆铌酸锂、锆铁双掺铌酸锂、锆铁锰及锆铜铈三掺铌酸锂。掺锆铌酸锂晶体不但在可见波段具有远优于掺镁铌酸锂的抗光损伤能力,即使在近紫外波段,也拥有其它掺杂晶体所不具备的抗光损伤性能。锆铁双掺铌酸锂晶体兼有高光折变灵敏度和高光折变衍射效率的性质。锆铁锰和锆铜铈三掺铌酸锂晶体不但能够实现非挥发存储,其光折变响应速度及灵敏度都较铁锰和铜铈双掺晶体有大幅提高。这些实验结果表明,掺锆铌酸锂有望成为出色的非线性光学晶体。     

封面说明

离散孤子的发现标志着从线性到非线性，从连续到非连续，从相干到非相干，人们对孤子认识的一个飞越．在非线性光学介质中利用人工制备或光学诱导波导阵列或光子晶格的方法来演示这种孤子态已成为一个便捷的方法．近期，陈志刚等人在二维光致光子晶格结构中空间离散光孤子的研究中，发现了基模离散孤子，类矢量离散孤子，     

Luminescent Enhancement in Mg- and Er-Codoped LiNbO3 Crystals

We investigate the MgO codoping-induced effect on the luminescent properties of Er^3 -doped and Er/Mg codoped LiNbO3 crystals. The emission and excitation spectra and the absorption spectra are measured. The results show that the luminescent behaviour of Er^3 ions is very sensitive to the codoping of Mg^2 ions. According to the photorefractive level theory, we propose a quench model for the Er/Mg codoped lithium niobate crystal. The quench centres are suggested to be the bipolaron (NbLi-NbNb), we attribute the luminescent enhancement to the decreasing concentration of these centres. The luminescent enhancement effect is successfully explained.     

掺镁铌酸锂晶体亚微米畴结构特性研究

基于畴背向反转效应，利用外加短脉冲极化电场，通过对脉冲宽度、脉冲间隔以及脉冲个数的有效控制，在掺5mol％镁的铌酸锂晶体上得到周期为1.7μm的均匀亚微米畴结构，其纵向深度为30—50μm.同时，使用脉冲宽度为100ms的宽脉冲信号得到了畴带宽度仅为0.5μm的非对称微畴结构对亚微米畴结构产生的微观机制和物理过程进行了初步探讨. 关键词： 背向反转效应 掺镁铌酸锂晶体 周期极化