旋转螺旋型中红外手性超材料的宽带圆二向色性  

Broadband Circular Dichroism of Rotating Helical-Typed Mid-Infrared Chiral Metamaterials

作　　者：张文涛[1] 施维捷 郭慧 闫长春 Zhang Wentao;Shi Weijie;Guo Hui;Yan Changchun(School of Physics and New Energy,Xuzhou Institute of Technology,Xuzhou,Jiangsu 221018,China;Jiangsu Key Laboratory of Advanced Laser Materials and Devices,School of Physics and Electronic Engineering,Jiangsu Normal University,Xuzhou,Jiangsu 221116,China)

机构地区：[1]徐州工程学院物理与新能源学院,江苏徐州221018 [2]江苏师范大学物理与电子工程学院江苏省先进激光材料与器件重点实验室,江苏徐州221116

出　　处：《激光与光电子学进展》2022年第5期246-253,共8页Laser & Optoelectronics Progress

基　　金：国家自然科学基金(61771227,62071208);江苏省高等学校大学生创新创业训练计划项目(201910320039Z)。

摘　　要：提出了由四个不同旋转方向的氧化铟锡(ITO)螺旋子单元组成的周期性中红外宽带手性结构。模拟结果显示,通过优化子单元螺旋的圈数、螺旋半径、螺距和螺旋线半径,该结构在中红外波段实现了良好的宽带圆二向色性(CD)。与两种非旋转螺旋结构比较发现,ITO旋转螺旋结构的CD带宽更宽。在波长7.95μm处,ITO旋转螺旋结构获得CD的最大值为0.454,CD的半峰全宽为7.5μm,波长范围从4.1到11.6μm。产生宽带CD的原因是四个不同旋转方向的ITO螺旋子单元之间存在较强的耦合。模拟结果还显示,在中红外波段,与金属(金和银)旋转螺旋结构相比,该ITO旋转螺旋结构表现出了良好的宽带CD,这为中红外波段宽带偏振态调控器件的设计提供了新的思路。A periodic mid-infrared broadband chiral structure is proposed,in which each unit is composed of four indium tin oxide(ITO)helical subunits in different rotating directions.The simulation results show that the flat-topped broadband circular dichroism(CD)can be achieved in the mid-infrared waveband by optimizing the number of helical turns,the helical radius,the pitch of helix,and the wire radius of helix.Compared with the two non-rotating helical structures,the CD band of the ITO rotating helical structure is found to be broader.At the wavelength of 7.95μm,for the ITO rotating helical structure,the maximum value of CD is 0.454 and the full width at half maximum(FWHM)of CD is 7.5μm in the wavelength ranging from 4.1 to 11.6μm.The broadband CD is caused by the strong coupling among the four ITO helical subunits in different rotating directions.The simulation results also show that compared with the gold and silver rotating helical structures,the proposed structure exhibits evidently better broadband CD,which provides a new idea for the design of broadband polarization state control devices in the mid-infrared band.

关 键 词：光学材料 氧化铟锡 旋转螺旋结构 中红外波段 手性超材料 圆二向色性 

分 类 号：TN214[电子电信—物理电子学]