基于稀土离子电磁偶极跃迁的光频超常介质研究

Metamaterials as a new class of artificial materials with novel physical properties and important application promise have been paid much attention recently. A trend for materials is much high working frequency. However，limitations from fabrication technique, physics principles and materials properties are encountered while the frequency assess to visible optical frequency. To overcome these limitations and develop new abnormal media with the properties of metamaterials in visible area, we propose a new electromagnetic response mechanism based on f-f electronic transition, including electric dipole transition and magnetic one in rare-earth ions in this proposal. Research include the investigation on the optical spectroscopy of rare-earth ions doped solids and novel electromagnetic response and their effect on the permittivity and permeability in transition resonance area, to explore a new nonmetamaterial rout for optical abnormal media and establish the theoretical framework for the design the materials. Left-handed materials based these mechanism will be synthesized, and the theoretical and experimental basis for these novel materials will be established.

基于人工结构（metamaterials）的超常电磁介质具有新颖的物理性质和重要的应用前景，近年来引起了越来越多的关注，并逐渐向高频方向发展。然而，这类人工结构材料在光学频段面临着加工技术、物理学和材料学极限。为了突破这些极限，发展可在光频下工作的超常介质，本项目提出了利用稀土离子f-f能级间的电偶极跃迁和磁偶极跃迁实现光频超常电磁响应的研究设想。拟在对镧系稀土离子f-f能级电磁偶极跃迁的光谱结构研究的基础上,探索f-f能级跃迁共振频率下的超常电磁响应及其宏观性质研究及其与稀土掺杂固体组成与性质的关系，发展出基于电子跃迁过程实现光频超常电磁响应的新途径，初步建立基于稀土f-f跃迁的本征型光频超常电磁介质的基本理论框架和材料设计原则，研制出基于上述机制的超常电磁介质材料，为发展非人工结构的新型光频左手材料等超常介质提供理论和实验基础。

基于人工结构（metamaterials）的超常电磁介质具有新颖的物理性质和重要的应用前景，近年来引起了越来越多的关注，并逐渐向高频方向发展。然而，这类人工结构材料在光学频段面临着加工技术、物理学和材料学极限。为了突破这些极限，发展可在光频下工作的超常介质，本项目提出了利用稀土离子f-f能级间的电偶极跃迁和磁偶极跃迁实现光频超常电磁响应的研究设想。在对镧系稀土离子f-f能级电磁偶极跃迁的光谱结构研究的基础上,该项目探索了f-f能级跃迁共振频率下的超常电磁响应及其宏观性质研究及其与稀土掺杂固体组成与性质的关系，发展出基于电子跃迁过程实现光频超常电磁响应的新途径，初步建立了基于稀土f-f跃迁的本征型光频超常电磁介质的基本理论框架和材料设计原则，为发展非人工结构的新型光频左手材料等超常介质提供理论和实验基础。我们根据半经典理论分析了稀土掺杂晶体中的二能级电子跃迁过程，获得了电磁参数与跃迁参数、稀土离子浓度的数学关系。在此基础上对一些典型稀土掺杂氧化物体系的超常电磁参数进行了模拟计算。结果表明：在跃迁频率处可以产生电谐振或磁谐振，且随掺杂浓度增加，谐振强度和谐振区宽度均增大；利用Sm3+和Yb3+共掺杂Y3Al5O12晶体，同时实现了960 nm处的电谐振和磁谐振，获得了带宽为0.57 MHz的负折射区。