| 题名 | 铽铝石榴石（TAG）磁旋光透明陶瓷的制备及性能研究 |
| 作者 | 陈冲 |
| 学位类别 | 博士 |
| 答辩日期 | 2015 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 周圣明 |
| 关键词 | TAG 磁致旋光材料 透明陶瓷 Verdet常数 热退偏 隔离度 |
| 其他题名 | Preparation and properties of terbium aluminum garnet (TAG) magneto-optical transparent ceramics |
| 中文摘要 | 磁致旋光材料作为磁光器件的关键组成部分，基于其非互易性在激光、光通讯、光纤传感等领域发挥着不可替代的作用，被广泛的应用于国防、医疗、工业等行业。随着磁光器件不断地朝着高功率、小型化、低成本等方向发展，对磁致旋光材料的要求也越来越高。与此同时，随着透明陶瓷技术的不断发展，其在力学、光学、热学等方面的优势使其得到较多的关注，也为磁致旋光材料的发展提供了新的途径。 铽铝石榴石(Tb3Al5O12,TAG)由于其在可见光区高的Verdet常数，可见及近红外波段宽的透过谱以及优异的物化性能等特性被认为是一种优良的磁致旋光材料。 因此，本论文选择TAG透明陶瓷作为研究对象，研究了TAG透明陶瓷的不同制备方法，稀土离子对TAG样品的磁光性能的影响以及不同烧结助剂对TAG陶瓷性能的影响；同时对所获得的样品在高功率隔离器中的应用进行了相关参数的测量评定。主要的工作内容如下： (1)采用固相反应真空烧结的方法制备了TAG透明陶瓷，通过调节升温速率、烧结温度和保温时间等优化了固相烧结制备工艺，对获得的TAG透明陶瓷样品的光学、磁光、显微结构及热学性能等进行了测试。实验结果显示获得的高质量TAG透明陶瓷，其在400-1600nm光谱范围内透过率为75%（样品厚度为3mm），没有杂相，几乎无气孔，Verdet常数在632.8nm处为-172.8rad T-1 m-1，此值与TAG晶体接近。室温下的热导率为6.4Wm-1K-1。 (2)分别采用固相反应真空烧结和两步法烧结制备了钇掺杂的TAG透明陶瓷。对介质相关性能的测试表明Y-TAG的成相几乎不受保温时间的影响，而适当延长烧结时间可以优化Y-TAG透明陶瓷的光学质量。本实验中，在保温24h条件下获得的样品的透过率最高，其在可见及近红外光区约为75%（样品厚度为2mm）。两步法烧结因为保温的温度较低可以有效的控制样品的晶粒尺寸，本实验中获得的样品的平均粒径约为8.66m，比其他样品小很多。 (3)稀土Ce离子掺杂的TAG透明陶瓷同样用固相反应真空烧结的方法获得，测试了Ce离子在掺杂浓度为0.3at%时样品的磁旋光系数为V=-199.55rad T-1 m-1，比未掺杂的纯TAG大16%。初步分析了Ce离子的掺杂使得Verdet常数增加的理论依据。 (4)研究了MgO，CeO2及TiO2作为烧结助剂对TAG透明陶瓷的透过率及显微结构的影响。实验发现MgO具有消除气孔，提高透过率的作用，其较佳的添加量为0.1wt%。对CeO2不同掺杂量及掺杂方式的TAG透明陶瓷进行的实验表明，CeO2也可以作为添加剂添加，它可以控制晶粒的生长，提高颗粒尺寸的均匀性，其较佳的掺杂量为0.1at%。TiO2作为添加剂的效果较好，获得的TAG透明陶瓷在可见及近红外波段透过率大于80%（样品厚度为3.5mm），其较佳的添加量为0.8at%。 (5)对TAG透明陶瓷样品在Faraday隔离器应用中的热退偏，热透镜等效应进行了实验研究，结果表明其在300W时的隔离度为38dB，预计在Kw级辐射功率下的隔离度仍然会在30dB以上。样品在300W时的热透镜效应焦距为8m。 (6)测量了基于Ce离子的掺杂浓度为0.01at%，0.05at%和0.1at%的TAG透明陶瓷样品的热退偏及热透镜效应。实验结果显示当Ce离子的掺杂浓度为0.05at%时样品的热退偏较佳。还设计了具有热退偏补偿的Faraday隔离器实验装置，结果显示Ce-TAG样品的热退偏降低很多，在300W时的隔离度为39dB。对基于Ce离子掺杂浓度为0.1at%的样品的热透镜效应随辐射功率的变化测试结果显示其在300W时热透镜效应的焦距为3.8m。 (7)对比了基于TGG，TAG及Ce-TAG（0.1at%）样品在高功率Faraday隔离器中应用的热退偏，热透镜等效应，得出：TAG透明陶瓷与TGG晶体的隔离度和热透镜效应均相当。TAG透明陶瓷的性能还可以通过退火处理进行提高，所以TAG透明陶瓷是可以制备Kw级的Faraday隔离器的 |
| 英文摘要 | Magneto-optical materials are essential part of the magneto optical devices. Due to the characteristic of non-reciprocal rotation, the material plays an irreplaceable role on laser system, optical communication, fiber sensing and other fields, and is widely used in national defense, medical, industrial and so on. With the development of the magnetic optical devices continuously towards high power, miniaturization and low cost, the requirements for the material are also getting higher. At the same time, with the development of transparent ceramics technology, the advantages of transparent ceramics in mechanics, optics and thermology attract much attention, and provide an alternative way for the development of magneto-optical materia Terbium aluminum garnet (Tb3Al5O12, TAG) is an excellent magneto-optical material with good transmittance in visible and near-infrared spectra and excellent physicochemical properties. Therefore, in this thesis, we choose TAG transparent ceramics as the research object; investigate its method of preparation, influence of rare earth ions on magneto optical properties and sintering additives on optical properties. The parameters of high power Faraday isolator (FI) based on the TAG transparent ceramic samples are also investigated. We mainly focused on the following contents: (1) TAG magneto-optical transparent ceramics were synthesized by solid state reaction and vacuum sintering. We optimized the sintering preparation process by adjusting the heating rates, sintering temperatures and holding times, and investigated the optical, magneto optical, microstructure and thermal property of the obtained TAG samples. The result showed that the optical transmittance was 75% (d=3 mm) in the region of 400-1600 nm, and there were no secondary phases and almost pore-free. The Verdet constant measured at 632.8 nm was -172.8 rad·T-1·m-1, which was comparable with that of TAG single crystal. The thermal conductivity was also measured which was 6.4Wm-1K-1. (2) The Y ions doped TAG magneto-optical transparent ceramics were synthesized by solid state reaction combined with vacuum sintering and two-step sintering, respectively. The property investigations showed that the phase formation of the Y: TAG transparent ceramic was hardly influenced by holding times. The sample showed highest optical transmittance which was about 75% (d=2 mm) in the visible and near infrared region when the holding time was 24h. The relatively lower holding temperature for the two-step sintering could control the average grain size which was 8.66m in our investigation and smaller than the other samples. (3) The Ce ions doped TAG magneto-optical transparent ceramics were synthesized by solid state reaction and vacuum sintering. The Verdet constant of Ce:TAG sample with doping content of 0.3at% measured at 632.8 nm was -199.55 rad·T-1·m-1, which was about 16% larger than that of pure TAG. A preliminarily theoretical analysis of the increasing of Verdet constant was also provided. (4) Influence of MgO, CeO2 and TiO2 as sintering aids on the optical transmittance and microstructures of TAG transparent ceramics were investigated. MgO had the function of eliminating pores and improving the optical transmittance, and its optimized addition was about 0.1 wt%. Research on different qualities of CeO2 doped TAG transparent ceramics showed that the Ce-doping had an obvious effect on controlling average grain size, homogenizing grain size, and could be a sintering additive with the optimized addition about 0.1 at%. TiO2 as an additive performanced the relatively better effect that the obtained TAG transparent ceramics had the transmittance over 80% (d=3.5 mm) in the visible and near infrared region, and its optimum adding amount was 0.8at%. (5) The thermally induced depolarization and thermal lens of TAG transparent ceramics were investigated experimentally. The samples showed a stable isolation ratio of 38 dB at 300 W. Estimates showed high performance that the isolation ratio would be 30 dB at a kilowatt laser power. The focal length of the thermal lens at 300 W was more than 8 meters. (6) Thermally induced depolarization of different qualities of CeO2 (0.01 at%, 0.05 at%, 0.1 at%) doped TAG transparent ceramics were investigated. The result showed that the superior sample was Ce:TAG containing 0.05% of cerium. FI with compensation of thermally induced depolarization was also studied and the result showed that the isolation ratio was about 39 dB at 300 W. The focal length of the thermal lens for FI based on Ce:TAG (0.1 at %) at 300 W was about 3.8 meters. (7) The performances of FI based on TGG, TAG and Ce: TAG magneto-optical ceramics for high average power laser system were compared. TAG transparent ceramics were comparable with TGG crystals in depolarization and thermal lens. Annealing treatment was expected to additionally reduce thermal distortions for TAG transparent ceramics. So, FIs based on TAG transparent ceramics for a kilowatt power level were viable. |
| 语种 | 中文 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15902]  |
| 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 | 陈冲. 铽铝石榴石（TAG）磁旋光透明陶瓷的制备及性能研究[D]. 中国科学院上海光学精密机械研究所. 2015. |
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