Three-layered metallodielectric nanoshells: plausible meta-atoms for metamaterials with isotropic negative refractive index at visible wavelengths.
Three-layered metallodielectric nanoshells: plausible meta-atoms for metamaterials with isotropic negative refractive index at visible wavelengths.
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DOI：
10.1364/oe.21.001076
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发表时间：
2013-01
期刊：
影响因子：
3.8
通讯作者：
Dajian Wu;Shumin Jiang;Ying Cheng;Xiao-jun Liu
中科院分区：
文献类型：
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作者：
Dajian Wu;Shumin Jiang;Ying Cheng;Xiao-jun Liu
提出了一种银-低介电常数-高介电常数的三层纳米壳层结构作为构建三维各向同性负折射率超材料的合理元原子。Ag-LP-HP纳米壳的电磁响应可以通过设计粒子的几何形状来实现，这可以导致负的电和磁极化。然后，在Ag-LP-HP纳米壳的随机排列中发现负折射率。特别地，中间LP层的调制可以将负折射率范围移动到可见光区。因为响应来自每个元原子，所以超材料本质上是各向同性的和偏振无关的。随着LP层厚度的增加，随机排列的负折射率范围出现较大的蓝移，并变窄。随着填充率的减小，负折射率范围蓝移，变窄，负折射率最大值减小。
A three-layered Ag-low-permittivity (LP)-high-permittivity (HP) nanoshell is proposed as a plausible meta-atom for building the three-dimensional isotropic negative refractive index metamaterials (NIMs). The overlap between the electric and magnetic responses of Ag-LP-HP nanoshell can be realized by designing the geometry of the particle, which can lead to the negative electric and magnetic polarizabilities. Then, the negative refractive index is found in the random arrangement of Ag-LP-HP nanoshells. Especially, the modulation of the middle LP layer can move the negative refractive index range into the visible region. Because the responses arise from the each meta-atom, the metamaterial is intrinsically isotropic and polarization independent. It is further found with the increase of the LP layer thickness that the negative refractive index range of the random arrangement shows a large blue-shift and becomes narrow. With the decrease of the filling fraction, the negative refractive index range shows a blue-shift and becomes narrow while the maximum of the negative refractive index decreases.