一种局域化协同增强太赫兹波电磁场的超材料  

A metamaterial for locally co-enhancing the electric and magnetic fields of THz wave

作　　者：张建新[1] 程海玉[2] ZHANG Jian-Xin1 , CHENG Hai-Yu2(1. College of Mechanical and Electrical Engineering, Jiaxing University, Jiaxing 314001, China; 2. Nanhu College, Jiaxing University,Jiaxing 314001,Chin)

机构地区：[1]嘉兴学院机电工程学院,浙江嘉兴314001 [2]嘉兴学院南湖学院,浙江嘉兴314001

出　　处：《光电子．激光》2018年第3期270-275,共6页Journal of Optoelectronics·Laser

摘　　要：设计了一种太赫兹(THz)波段的超材料,可以实现对垂直入射THz波的电、磁场局域化协同增强。数值仿真表明,在线偏振的THz脉冲垂直辐照下,利用本文超材料的结构能得到强显著增强且高度局域化的电、磁场分布,入射THz波的电、磁场分量可以分别增强20倍和14倍;被增强的电、磁场局域化在μm2尺度范围内,且在空间上不重叠。基于等离激元理论分析了超材料内部的面电流分布以及超材料内部电荷的积累,给出了电磁场协同增强及局域化的理论解释,即超材料的特殊结构产生的电容效应及面电流的汇聚作用分别是导致电、磁场协同局域化增强的原因。最后,具体分析了超材料关键的几何参数对于场增强效果的影响。本文提出的超材料方案,有望应用于THz波段近场光学、非线性光学及THz波与磁有序介质相互作用等领域。A kind of metamaterial aiming at locally co-enhancing the electric and magnetic fields of the incident pulse at terahertz （THz） band is designed.Numerical simulation demonstrates that a remarkable enhanced and highly localized electromagnetic filed is expected to be generated utilizing the struct ure under the irradiation of normal incident terahertz pulse,and 20and 14times of magnitude of enhancement for the electric and magnetic components of the incident pulse are expected,respectively.The enhanced el ectric and magnetic fields are confined in an area of μm2scale without spatial overlap.Theoretical explanat ion of the local enhancement of the electric and magnetic fields is given via analyzing the surface curre nt distribution and the charge accumulation of the structure based on the plasmon theory.The capacita nce effect and aggregation effect of surface current engendered by the specially designed structure of the metamateri al are the causes of local enhancement of the electric and magnetic fields.Moreover,the key geometry parame ters on the field enhancement are analyzed concretely.The proposed metamaterial is hopeful to be applied to ma ny fields,such as THz near-field optics,nonlinear optics and the interaction of THz wave with magnetically ordered structure,etc.

关 键 词：超材料 太赫兹(THz) 场加强 表面等离激元 

分 类 号：O441[理学—电磁学]