Active Chiral Plasmonics
Active Chiral Plasmonics
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DOI：
10.1021/nl5042325
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发表时间：
2015-07-01
期刊：
影响因子：
10.8
通讯作者：
Giessen, Harald
中科院分区：
文献类型：
--
作者：
Yin, Xinghui;Schaeferling, Martin;Giessen, Harald
主动控制手性超材料的旋向性具有作为高度集成的偏振工程方法、偏振敏感成像器件和立体显示技术的关键元件的潜力。然而，这是难以实现的，因为它似乎涉及将超分子从左手对映异构体重新配置为右手对映异构体，反之亦然。这种类型的机械致动是复杂的，通常既不能单片实现，也不适用于高速应用。在这里，通过相变材料Ge 3Sb 2 Te 6（GST-326），我们在概念验证实验中展示了可调谐和可切换的中红外等离子体手性超材料。实现了从λ = 4.15到4.90 μ m的圆二色性响应的大的可调谐性范围，并且我们实验证明，被动偏置型手性层与主动手性超材料的组合允许可切换的手性，即，圆二色性符号的反转，在完全平面的分层设计中，而不需要几何重构。由于相变材料可以进行电和光切换，我们的设计可能会为高度集成的中红外偏振工程设备开辟一条道路，这些设备可以在超快时间尺度上进行调制。
Active control over the handedness of a chiral metamaterial has the potential to serve as key element for highly integrated polarization engineering approaches, polarization sensitive imaging devices, and stereo display technologies. However, this is hard to achieve as it seemingly involves the reconfiguration of the metamolecule from a left-handed into a right-handed enantiomer and vice versa. This type of mechanical actuation is intricate and usually neither monolithically realizable nor viable for high-speed applications. Here, enabled by the phase change material Ge3Sb2Te6 (GST-326), we demonstrate a tunable and switchable mid-infrared plasmonic chiral metamaterial in a proof-of-concept experiment. A large tunability range of the circular dichroism response from lambda = 4.15 to 4.90 mu m is achieved, and we experimentally demonstrate that the combination of a passive bias-type chiral layer with the active chiral metamaterial allows for switchable chirality, that is, the reversal of the circular dichroism sign, in a fully planar, layered design without the need for geometrical reconfiguration. Because phase change materials can be electrically and optically switched, our designs may open up a path for highly integrated mid-IR polarization engineering devices that can be modulated on ultrafast time scales.