双掺杂LiNbO_3晶体非挥发全息记录的理论和实验研究
文献类型：学位论文
| 作者 | 刘友文 |
| 学位类别 | 博士 |
| 答辩日期 | 2001 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 刘立人 |
| 关键词 | 光折变效应 双掺杂铌酸锂晶体 非挥发性全息记录 光固定 |
| 中文摘要 | Buse等人在双掺杂Fe:Mn铌酸锂晶体实现的非挥发性(nonvolatile)全息记录[Nature，393，665(1998)]不但是一种有应用前景的光固定全息方法，而且也是一利晶体中记录局域体全息的全光的方法。本论文论述了作者在双掺杂铌酸锂晶体非挥发性全息记录的理论和实验的研究工作：(1)考虑了扩散、漂移和光伏打效应三种输运机制，用二中心带输运模型理论分析了在小调制度近似下双掺杂品体用双色光进行非挥发性全息记录的动力学过程，得出一组描述记录动力学的耦合微分方程组。数值求解并解释了双掺杂晶体全息记录的动态发展过程，分析求解给出了记录和固定的稳态空间电荷场的分析表达式。得到非挥发性全息记录的一些重要的条件和新的结论。理论分析结果与已有的实验结果一致。在此基础上提出了优化全息记录的方案，对掺Mn:Fe铌酸锂晶体即晶体需高氧化、合适的掺锰浓度(约为掺铁浓度的十分之一)和高红光-紫外光强比(30倍左右)。(2)对四种不同掺杂Cu:Ce、Mn:Cu：Ce、Mn:Fe和Mn:Fe:Mg铌酸锂品体，在强氧化和还原两种状态下进行了紫外光敏化和红光记录的非挥发性全息存储实验研究，对它们的全息记录性质进行了比较。实验结果进一步验证了我们的理论研究结果。首次用除掺Mn:Fe铌酸锂晶体之外其它不同深度能级掺杂的品体实现非挥发性全息存储，与掺Mn:Fe铌酸锂晶体相比，掺Cu:Ce铌酸锂晶体具有高固定衍射效率和低光致散射的优点。(3)提出了用蓝光代替紫外光作敏化光的记录方法，并在LiNbO_3:Cu:Ce晶体中实现了非挥发性全息存储，并对这两利记录方法的饱和(非挥发)和光固定衍射效率、光致散射效应进行了比较和讨论。在这种记录方法下，我们进一步实验研究了记录光和敏化光光强、光栅周期和掺杂浓度对这种全息记录的影响，并通过优化光强比来优化全息记录。 |
| 英文摘要 | Nonvolatile holographic recording in lithium niobate crystals doubly doped with Fe:Mn proposed by Buse et al. [Nature, 393, 665(1998)] is not only a promising method for optically fixing holograms, but also an ail-optical method for recording a local volume holograms in photorefractive crystals. In this dissertation, experimental and theoretical studies of nonvolatile holographic recording in doubly doped lithium niobate crystals are presented: (1) Considering all three transport mechanisms of diffusion, drift and the photovoltanic effect and using two-center band transport model, we set up a set of coupling differential equations that describe the dynamics of the nonvolatile holographic recording in doubly-doped lithium niobate crystals in the case of small signal and modulation. The equations are solved numerically to explain the time dynamic development processes of holographic recording, and solved analytically to obtain the expressions of the recorded and fixed steady-state space-charge fields. Some important conditions and effects of the nonvolatile holographic recording are found, and the results are well consistent with the reported experimental results. On the basis of these results, an optimal prescription for material doping, oxidation/reduction processing and red-UV intensity ratio is suggested in which a high oxidation, a suitable Mn-doping density (nearly 1/10 order small then Fe-doping density), and a high red-UV intensity ratio about 30) are required for lithium niobate doubly doped with Fe:Mn. (2)Four lithium niobate crystals doped with Cu:Ce, Mn:Cu:Ce, Mn:Fe, and Mn:Fe:Mg, which are processed under two different oxidation/reduction conditions, are studied experimentally ior non-volatile holographic recording with ultraviolet for sensitizing and red light for recording, and their nonvolatile holographic recording properties are compared. The results further prove our theoretical conclusions. To the best of our knowledge, the non-volatile holographic storage in lithium niobate doped with Cu:Ce and Cu:Ce:Mn crystals is first realized, and lithium niobate crystals doped with Cu:Ce have advantages of high persistent diffraction efficiency and weak light-induced scattering in contrast to lithium niobate crystals doped with Fe:Mn. (3) A new program of nonvolatile holographic recording is proposed in which a blue beam is used for sensitizing instead of UV beam, and is realized in lithium niobate crystals doped with Cu:Ce. The saturation (persistent) diffraction efficiency, optical fixing efficiency and light-induced scattering effect with two methods are compared and discussed. Based on the recording method with blue light for sensitizing, the effects of intensities of recording and sensitizing beams, grating period, doping density on properties of nonvolatile holographic recording are studied experimentally, and holograms are optimized by changing intensities of recording and sensitizing beams. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15459]  |
| 专题 | 上海光学精密机械研究所_学位论文 |
| 推荐引用方式 GB/T 7714 | 刘友文. 双掺杂LiNbO_3晶体非挥发全息记录的理论和实验研究[D]. 中国科学院上海光学精密机械研究所. 2001. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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