Nanofabricated media with negative permeability at visible frequencies
Nanofabricated media with negative permeability at visible frequencies
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DOI：
10.1038/nature04242
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发表时间：
2005-11-17
期刊：
影响因子：
64.8
通讯作者：
Petrovic, J
中科院分区：
文献类型：
--
作者：
Grigorenko, AN;Geim, AK;Petrovic, J
最近，大量的注意力集中在一种新的智能材料上--所谓的左手介质--它表现出非常不寻常的电磁特性，并有望实现新的设备应用(1-6)。左手材料需要负磁导率m，这是一种极端的条件，到目前为止，只有在微波到太赫兹(7-11)的频率范围内才能实现。参考文献中所述方法的扩展。7在可见光中实现必要的高频磁响应是一项艰巨的挑战(12-15)，因为已知没有任何材料--无论是天然的还是人造的--在这些频率上显示出任何磁性。在这里，我们报告了一种由电磁耦合的金点对组成的纳米软化介质，其几何形状精心设计在10纳米的水平上。该介质在可见光频率下表现出很强的磁响应，包括一个负m带。该磁响应是由于反对称等离子体共振的激发而产生的。高频磁导率通过光阻抗匹配得到定性的反映。我们的结果证明了在可见光频率工程磁性的可行性，并为可见光学的磁性和左手组件铺平了道路。
A great deal of attention has recently been focused on a new class of smart materials-so-called left-handed media-that exhibit highly unusual electromagnetic properties and promise new device applications(1-6). Left-handed materials require negative permeability m, an extreme condition that has so far been achieved only for frequencies in the microwave to terahertz range(7-11). Extension of the approach described in ref. 7 to achieve the necessary high-frequency magnetic response in visible optics presents a formidable challenge(12-15), as no material-natural or artificial-is known to exhibit any magnetism at these frequencies. Here we report a nanofabricated medium consisting of electromagnetically coupled pairs of gold dots with geometry carefully designed at a 10-nm level. The medium exhibits a strong magnetic response at visible-light frequencies, including a band with negative m. The magnetism arises owing to the excitation of an antisymmetric plasmon resonance. The high-frequency permeability qualitatively reveals itself via optical impedance matching. Our results demonstrate the feasibility of engineering magnetism at visible frequencies and pave the way towards magnetic and left-handed components for visible optics.