基于Ag纳米棒阵列的表面等离激元微型偏振器  

Surface Plasmonic Micropolarizers Based on Ag Nanorod Arrays

作　　者：于杰[1] 张俊喜[1] 张立德[1] 费广涛[1] 

机构地区：[1]中国科学院固体物理研究所材料物理重点实验室,安徽合肥230031

出　　处：《光学学报》2014年第7期205-209,共5页Acta Optica Sinica

基　　金：国家自然科学基金(10804112);国家973计划(2012CB932303)

摘　　要：采用静电近似理论计算了Ag纳米棒阵列在不同偏振光入射下的消光光谱。当入射光偏振方向平行于纳米棒长轴时会激发表面等离激元纵向振动模式,而当入射光偏振方向垂直于纳米棒长轴时会激发表面等离激元横向振动模式。基于两种模式共振波长的不同,采用Ag纳米棒阵列可以用来设计高性能的表面等离激元微型偏振器。Ag纳米棒阵列的偏振性能在纵向共振波长明显优于在横向共振波长,通过调节纳米棒的纵横比可以对纵向模式的共振峰位进行大范围调控。结果表明这种微型偏振器所适用的波长能够通过纳米棒的纵横比在可见到近红外波段范围内调控,而消光比和插入损耗能够通过纳米棒的直径和长度实现调控。Extinction spectra of Ag nanorod arrays under incident light with different polarization directions are calculated by an electrostatics approximation theory. A longitudinal resonance mode of the localized surface plasmons （LSPs） can be excited when the polarization direction is parallel to the long axis of the nanorods, while a transversal resonance mode of the LSPs can be excited when the polarization direction is perpendicular to the long axis. In this case, high-performance plasmonic micropolarizers based on the different resonance wavelengths of the two modes can be designed by use of the Ag nanorod arrays. The polarization property of the Ag nanorod arrays at the longitudinal resonance wavelengths is prominently better than that at the transversal resonance wavelengths, and the resonance peak of the longitudinal mode can be tuned in a broad spectra region by adjusting the aspect ratio of the nanorods. The wavelength of the micropolarizers can be tuned from the visible to near-infrared spectra region by changing the aspect ratio of the nanorods. Moreover, the extinction ratio and insertion loss can also be adjusted by control of the diameter and length of the nanorods.

关 键 词：表面光学 表面等离激元 微型偏振器 纳米棒阵列 纵向振动模式 横向振动模式 

分 类 号：O436[机械工程—光学工程]