摘要
采用三维时域有限差分方法,对比研究了石英基底上周期性亚波长圆形、纽扣形、半圆形和太极形四种具有不同对称性的孔阵列微结构金属膜的增强光透射特性,并分别探讨了阵列周期、小孔尺寸对这四种阵列结构透射特性的影响.结果表明增强光透射特性对单元结构对称性具有很强的依赖性:在超短高斯光脉冲激励下,随着单元结构对称性的降低,归一化透过率逐渐增大,红外波段的透射峰发生大量红移,且其与可见光波段的透射峰之间的距离逐渐增大,在对称性破缺的太极形孔阵列中两峰间距最大,可达1 300nm左右.表面等离激元模式与局域表面等离子体共振模式在增强光透射现象中起着重要的作用.在可见光波段,表面等离激元模式是这四种阵列结构的光透射增强的主导性因素;在红外波段,局域表面等离子体共振模式对单元结构对称性较差孔阵列结构的增强光透射特性有着显著影响.
3Dfinite-difference time-domain method was employed to comparatively study the enhanced optical transmission of four kinds of periodic subwavelength hole arrays metallic films,such as circularshaped,button-shaped,semicircular-shaped and Tai-Chi-shaped holes which had different symmetries and were deposited on a quartz substrate.The effect of the hole arrays periodicity and the hole size on the enhanced optical transmission of these four array structures were investigated.The results show that the enhanced optical transmission is strongly dependent on the symmetries of unit cells.Under the excitation of ultrashort Gauss light pulse,the normalized transmission increases gradually with the reduction of unit structural symmetries,the transmission peak in infrared wavelengths range undergoes a large spectral red-shift.The distance between the transmission peak in visible and infrared wavelengths range increases gradually.The largest distance of 1 300 nm is in symmetry breaking Tai-Chi-shaped arrays.The surface plasmon polaritons mode and the localized surface plasmon resonance mode play important roles in the process of the enhanced optical transmission.In visible wavelengths,the surface plasmonic polaritons mode is the dominant factor to the enhanced optical transmission of these four arrays structures.In infrared wavelengths,the localized surface plasmon resonance mode significantly affects the enhanced optical transmission of the hoel arrays in poor unit symmetries.
出处
《光子学报》
EI
CAS
CSCD
北大核心
2015年第11期62-70,共9页
Acta Photonica Sinica
基金
国家自然科学基金项目(No.11174119)
南华大学重点学科建设项目(No.NHXK04)资助~~
关键词
亚波长金属孔阵列
增强光透射
时域有限差分
单元结构对称性
表面等离激元
Subwavelength metallic hole arrays
Enhanced optical transmission
Finite-difference Time-domain
Unit structural symmetries
Surface plasmon polaritons
