介质掺杂近零媒质中光场增强效应及其应用  

Optical field enhancements and applications by epsilon-nearzero medium with dielectric dopant

作　　者：赵林[1,2] 冯一军[1] Zhao Lin;Feng Yi-Jun(School of Electronic Science and Engineering,Nanjing University,Nanjing 210093,China;School of Electronic Engineering,Naval University of Engineering,Wuhan 430033,China)

机构地区：[1]南京大学电子科学与工程学院,南京210093 [2]海军工程大学电子工程学院,武汉430033

出　　处：《物理学报》2020年第15期39-45,共7页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:61671231,61801207)资助的课题.

摘　　要：电磁场的汇聚与增强是电磁学中一个重要的研究内容,具备场汇聚与增强特性的电磁(光学)器件在高方向性电磁天线、激光点火、光学调控等方面有着广泛的应用前景.目前,电磁场增强的途径主要有两种,一是采用构造人工电磁材料结构以实现辐射方向的控制和能量集中,其次是采用具有高介电常数或高磁导率的材料来实现电磁场增强,但是上述两种方式应用在光学波段具有一些局限性.本文基于光子晶体掺杂理论,通过介质掺杂近零媒质的方式成功实现了光场增强功能.理论分析和数值仿真计算表明所设计的结构能够显著实现场强增强,并适用于微波至光波波段,应用频谱范围很宽.作为应用探索,本文还设计了一款工作在270 nm波长的紫外光波段点火装置.上述工作为新型电磁(光学)器件的研制提供了新的思路.Field enhancement is an interesting and important topic in electromagnetic study.Electromagnetic field concentration and enhancement devices have wide applications in high directional antenna design,laser ignition,optical control,etc.At present,there are usually two ways of implementing the field enhancement,one is to use the artificial electromagnetic materials to realize the radiation direction control and energy concentration,which is more suitable for the applications at microwave or lower frequencies,and the other is to use the materials with high permittivity or high permeability.However,the latter is extremely sensitive to the position and characteristic of the radiation source and the cross-sectional area of the material,and depends heavily on the value of the relative permittivity or the relative permeability of the material.Therefore,both methods cannot fully meet the application requirements of creating high field intensity in optical band,such as laser ignition,etc.In this paper,based on the theory of photonic crystal doping,the strong electromagnetic field enhancement has been successfully realized by epsilon-near-zero medium filled with ordinary dielectric dopant.We first make the comprehensive theoretical analysis of the field enhancement in the structure of epsilon-near-zero medium with dielectric dopant.The method of calculating the central magnetic field in the doped medium is then rigorously derived,and the formula for the ratio of the central magnetic field in the doped medium to the external radiation field is deduced.We find that the optimal magnetic field enhancement occurs only when the proposed structure is equivalent to an epsilon-mu-near-zero medium.Subsequently,under the above condition,various parameters(radius of the cylindrical dopant,number of sources,etc.)are studied to analyze the magnetic field enhancement performance inside the doped medium.The theoretical analysis and simulation results show that the proposed structure can significantly enhance the magnetic field which is appl

关 键 词：近零媒质 介质掺杂 电磁场增强 

分 类 号：O441[理学—电磁学]