亚波长单金属槽电磁场增强分析  

Electromagnetic Enhancement by a Single Subwavelength Groove in Metallic Substrate

作　　者：张斯文[1] 刘海涛[1] 母国光[1] 

机构地区：[1]南开大学信息技术科学学院现代光学研究所光电信息技术科学教育部重点实验室,天津300071

出　　处：《中国激光》2011年第3期191-196,共6页Chinese Journal of Lasers

基　　金：国家自然科学基金(10804057);国家973计划基金(2007CB307001);教育部高等学校科技创新工程重大项目培育资金(708021);教育部"新世纪优秀人才支持计划"(NCET-08-0289)资助课题

摘　　要：针对金属微纳结构在表面增强拉曼光谱领域的应用,研究了金属基底亚波长单槽结构产生的电磁场增强。采用全矢量方法严格计算了平面波照明下金属槽外部区域电磁场的分布情况。建立了法布里-珀罗(F-P)半解析模型,该模型能够精确预言全矢量方法的计算结果,能够节省设计最优槽深的计算量。基于该模型分析了金属槽外部区域电场增强的物理机制,结果表明达到相长叠加共振状态的金属槽内基模在槽外空间中激励的透射电场是金属槽外空间中电场增强的主要来源。研究了槽外空间电场增强的范围,结果表明对于不同的槽宽和入射波长,在垂直距离槽口0.1倍波长的范围内电场增强较为明显,在该范围之外,电场增强因子迅速衰减到1的数量级。The electromagnetic enhancement generated by a single subwavelength groove in metallic substrate is analyzed for the application of surface enhanced Raman scattering（SERS） on metallic micronano-structure.The electromagnetic field distribution out of the groove illuminated by a plane-wave is calculated using fully-vectorial numerical method.The rigorous fully-vectorial data are well predicted by a simple semi-analytical Fabry-Perot（F-P） model.The computation amount for designing the optimal groove depth can be saved by using the model.Physical mechanism of electric-field enhancement out of the groove,based on the model is analysed,which shows that the enhancement is mainly attributed to the transmitted field of enhanced fundamental groove mode under resonance.The range of the enhanced electric-field out of the groove is studied.The results show that,for different groove widths and illumination wavelengths,the electric-field enhancement is considerable at vertical distances to the groove mouth less than 0.1 times of the wavelength and that out of this range,the electric-field enhancement factor attenuates rapidly to about unitary magnitude.

关 键 词：光谱学 表面增强拉曼光谱 电磁场增强 亚波长单金属槽 全矢量数值方法 法布里-珀罗模型 

分 类 号：O436[机械工程—光学工程]