基于零折射率介质的超窄带光学滤波器  

An ultra-narrow-band optical filter based on zero refractive index metamaterial

作　　者：周晓霞 陈英 蔡力[2] Zhou Xiao-Xia;Chen Ying;Cai Li(School of Electronic Information and Electrical Engineering,Changsha University,Changsha 410000,China;Laboratory of Science and Technology on Integrated Logistics Support,College of Intelligence Science,National University of Defense Technology,Changsha 410073,China)

机构地区：[1]长沙学院电子信息与电气工程学院,长沙410000 [2]国防科技大学,智能科学学院装备综合保障技术重点实验室,长沙410073

出　　处：《物理学报》2023年第17期218-224,共7页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:51975575)资助的课题.

摘　　要：本文提出一种基于零折射率介质的超窄带光学滤波器.在线缺陷光学滤波器中引入具有类狄拉克点的光学超构材料,利用其零折射效应来实现滤波带宽的压缩.基于COMSOL Multiphysics软件的传输特性分析表明,当超构材料的类狄拉克点频率与缺陷态的谐振频率相符合时,光学滤波器的透射峰能够显著压缩;光场分布及等效介质分析表明,零折射率介质的零相位延迟效应与强色散特性能够增强缺陷态透射电磁响应随频率变化的灵敏度,提高滤波器的品质因子,并能在压缩滤波带宽的同时保持高的峰值透射率,实现高耦合、超窄带的滤波设计.该结果为基于光学超构材料的波分复用系统设计与应用提供了新的技术思路.Owing to the photonic band gap effect and defect state effect,photonic metamaterials have received much attention in the design of narrow bandpass filters,which are the key devices of optical communication equipment such as wavelength division multiplexing devices.In this work,based on zero-index metamaterial(ZIM),a compact filter with both high peak transmission coefficient and ultra-narrow bandwidth is proposed.The photonic metamaterial with conical dispersion and Dirac-like point is achieved by optimizing the structure and material component parameters of dielectric rods with square lattice in air.It is demonstrated that a triply degenerate state can be realized at the Dirac-like point,which relates this metamaterial to a zero-index medium with effective permittivity and permeability equal to zero simultaneously.Electromagnetic(EM)wave can propagate without any phase delay at this frequency,and strong dispersion occurs in the adjacent frequency cone,leading to dramatic changes in optical properties.We introduce a ZIM into photonic metamaterial defect filter to compress the bandwidth to the realization of ultra-narrow bandpass filter.The ZIM is embedded into the resonant cavity of line defect filter,which is also composed of dielectric rods with square lattice in air.In order to increase the sensitivity of the phase change with frequency,the Dirac-like frequency is adjusted to match the resonant frequency of the filter.We study the transmission spectrum of the structure through the COMSOL Multiphysics simulation software,and find that the peak width at half-maximum of the filter decreases as the thickness of ZIM increases,and the peak transmittance is still high when bandwidth is greatly compressed.The zero phase delay inside the slab can be observed.Through field distribution analysis,the zerophase delay and strong coupling characteristics of electromagnetic field are observed at peak frequency.The comparison with conventional photonic metamaterials filter is discussed.We believe that this work is helpful in i

关 键 词：光学超构材料 窄带滤波器 零折射率 类狄拉克点 

分 类 号：TN713[电子电信—电路与系统]