Enhanced and tunable circular dichroism in the visible waveband by coupling of the waveguide mode and local surface plasmon resonances in double-layer asymmetric metal grating  

作　　者：Liu-Li Wang Yang Gu Yi-Jing Chen Ya-Xian Ni Wen Dong 王刘丽;顾阳;陈怡静;倪亚贤;董雯(School of Physical Science and Technology,Soochow University,Suzhou 215006,China;Soochow College,Soochow University,Suzhou 215006,China)

机构地区：[1]School of Physical Science and Technology,Soochow University,Suzhou 215006,China [2]Soochow College,Soochow University,Suzhou 215006,China

出　　处：《Chinese Physics B》2022年第11期599-604,共6页中国物理B（英文版）

基　　金：Project supported by the National Natural Science Foundation of China(Grant No.11474215)。

摘　　要：Circular dichroism(CD)has shown very interesting possibilities as a means to characterize the chiral signal of a chiral structure.Here,we theoretically demonstrated enhanced and tunable CD in the visible light regime using a composite structure consisting of a double-layer metal grating gaped by a dielectric waveguide layer.Based on the coupling of the waveguide modes and the localized plasmonic resonances,the CD could reach a maximum value as high as 0.52 at635 nm,which is four times higher than the CD value obtained in a conventional double-layer grating without the waveguide coupling effect.Furthermore,the spectral positions of the enhanced CD bands could be easily tuned by controlling the structural parameters.The proposed hybrid double-grating and waveguide structures could have potential applications in chiral selective imaging,sensing and spectroscopy,especially where the transmission measurement is required.

关 键 词：circular dichroism chiral metamaterial WAVEGUIDE surface plasmon 

分 类 号：O48[理学—固体物理] O53[理学—物理]