Optical characteristics of rounded silver nanoprisms
Optical characteristics of rounded silver nanoprisms
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DOI：
10.1007/s10043-016-0188-8
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发表时间：
2016-02
期刊：
影响因子：
1.2
通讯作者：
Tomohiro Mori;K. Yamaguchi;Yasuhiro Tanaka;Y. Suzaki;M. Haraguchi
中科院分区：
文献类型：
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作者：
Tomohiro Mori;K. Yamaguchi;Yasuhiro Tanaka;Y. Suzaki;M. Haraguchi
采用三维时域有限差分法对圆角银纳米棱镜的光学特性进行了数值分析。通过在纳米棱镜角处引入大的曲率半径使得其变成圆柱体，电场的增强从240倍降低到13倍。这导致光学多模改变为单偶极模。在使用蝴蝶结结构的最大局部电场增强中，该蝴蝶结结构由一对具有圆角的纳米棱镜组成（曲率半径和差距距离分别为8.66和1 nm），电场在热点处增强了360倍。具有非零曲率半径的蝴蝶结结构产生比没有曲率半径的单个纳米棱镜更大的电场增强。数值模拟还表明，曲率半径的变化和差距距离的变化对电场增强的影响是一致的。
We analyzed numerical optical characteristics of silver nanoprisms with rounded corners using the three-dimensional finite-difference time-domain method. The enhancement of the electric field was decreased from 240 to 13 times by introducing a large radius of curvature at the nanoprism corners such that it became a cylinder. This caused the optical multi-mode to change to single dipole mode. In the largest local electric field enhancement using the bowtie structure, which consisted of a pair of nanoprisms with rounded corners (the curvature radius and the gap distance were 8.66 and 1 nm, respectively), the electric field was enhanced by a factor of 360 at the hotspot. The bowtie structure that has non-zero curvature radii produces a larger electric field enhancement than does the single nanoprism without a curvature radius. Furthermore, the numerical simulation elucidates that the change of the curvature radius and the change of the gap distance have the same influence on the electric field enhancement.