一维金属光栅嵌入磁性介质纳米结构下的横向磁光克尔效应的增强  

Great enhancement of transversal magneto-optical Kerr effect for magnetic dielectric film embedded by one-dimensional metallic grating

作　　者：陈聿[1] 刘垄[1] 黄忠[1] 屠林林[1] 詹鹏[1] 

机构地区：[1]南京大学物理学院固体微结构物理国家重点实验室,南京210093

出　　处：《物理学报》2016年第14期253-260,共8页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:11274160);国家自然科学基金重大研究计划(批准号:91221206)资助的课题~~

摘　　要：本文在一维金属光栅嵌入磁性介质的体系中实现了横向磁光克尔效应的增强.通过最优化金属光栅的嵌入深度来有效激发磁性介质中的波导模式与金属条带上的局域等离激元模式,从而使横向磁光克尔效应的响应得到巨大增强.本文提出了一种用于增强横向磁光克尔效应的新型等离激元微纳结构,这种结构可以应用于高性能磁光器件的设计.Transversal magneto-optical Kerr effect（TMOKE） has potential practical applications, such as biosensors, magnetic imaging, and date storage. However, these potential applications have been restricted by its very weak response（about 0.1%） in natural ferromagnetic metal material such as Fe, Co and Ni. Fortunately, with the development of the nanofabrication techniques, surface plasmons（SPs） are one of the effective strategies to solve this problem due to their special ability to manipulate light on a nanoscale and concentrate the electromagnetic energy near the metal/dielectric interface. Herein, in order to enhance the TMOKE response, we propose that a periodic gold strips array is embedded into a magnetic dielectric film of bismuth iron garnet（BIG）, which is supported by a quartz substrate. Using the finite element method, we numerically study the optical properties of our proposed microstructure and the corresponding evolution of the TMOKE responses due to the coupled optical modes dependent on the structural parameters. Particularly,by optimizing the embedded depth of metal grating, a dramatic enhancement of TMOKE response（about 3.6%） is achieved when the embedded depth reaches up to 80 nm, accompanied with a high transmissivity about 22.6%, which is actually three time larger than that in the case that the gold strips are just patterned on the surface of the BIG film.As the embedding depth increases further, the TMOKE response will be weak. The relationship between the TMOKE response and the coupling efficiency of LSP resonance of the gold stripes and the waveguide（WG） mode supported by the BIG film are also discussed systematically. As the embedding depth increases up to 80 nm gradually, the coupling of the WG mode in BIG film with the LSP mode of the individual gold stripe becomes much stronger and forms a highly efficient Fano resonance, which leads to the fact that most of the electromagnetic field is localized in the BIG film and strong interaction with the BIG magnetic dielectric

关 键 词：表面等离激元 横向磁光克尔效应 磁性介质 波导模式 

分 类 号：TB383.1[一般工业技术—材料科学与工程] O482.5[理学—固体物理]