多层金属-介质镀膜光栅的聚焦特性  

Focusing Properties with a Single Subwavelength Slit Flanked by Metal-Dielectric Multilayer Grating

作　　者：李慧[1] 闫连山[1] 潘炜[1] 罗斌[1] 温坤华[2] 郭振[2] 

机构地区：[1]西南交通大学信息科学与技术学院信息光子与通信研究中心,四川成都610031 [2]中国科学院光电技术研究所微细加工光学技术国家重点实验室,四川成都610029

出　　处：《激光与光电子学进展》2012年第1期152-155,共4页Laser & Optoelectronics Progress

基　　金：国家973计划(2011CB301800);新世纪优秀人才支持计划(NCET-08-0821);微细加工光学技术国家重点实验室基金资助课题

摘　　要：结合等离子金属光栅原理和多层膜理论,提出一种金属-介质-金属多层光栅结构以增强透射光的聚焦效应。利用时域有限差分(FDTD)法对该多层结构的聚焦特性进行模拟仿真,得到多层结构的聚焦特性随金属-介质膜层数和凹槽数目的变化特性。结果表明,通过控制金属-介质层层数或者凹槽数目,焦距明显改善,焦距可达9.15μm,最大焦深约为26.38μm,相对于传统金属光栅,聚焦效应得到了明显增强。Based on plasmonic metal grating mechanism and multilayer theory, a subwavelength slit with metal- dielectric multilayer composite surface grating which can enhance focusing effect is proposed. According to the finite difference-time domain （FDTD） method, the numerical simulation results demonstrate that the focusing behaviors of the designed structure is related to the numbers of metal-dielectric layers and grooves. It is found that the focal length can be increased significantly by controlling the number of metal-dielectric layers. The maximum focal length and the maximum focus depth can reach 9.15 and 26.38 μm, respectively. Therefore, the focusing performances are enhanced obviously compared with conventional mono-metal gratings.

关 键 词：薄膜 表面等离子 亚波长结构 多层膜设计 

分 类 号：O484.4[理学—固体物理] TH74[理学—物理]