Induced Chirality through Electromagnetic Coupling between Chiral Molecular Layers and Plasmonic Nanostructures

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• 作者：Nadia A. Abdulrahman ; Z. Fan ; Taishi Tonooka ; Sharon M. Kelly ; Nikolaj Gadegaard ; Euan Hendry ; Alexander O. Govorov ; Malcolm Kadodwala
• 刊名：Nano Letters
• 出版年：2012
• 出版时间：February 8, 2012
• 年：2012
• 卷：12
• 期：2
• 页码：977-983
• 全文大小：364K
• 年卷期：v.12,no.2(February 8, 2012)
• ISSN：1530-6992

文摘

We report a new approach for creating chiral plasmonic nanomaterials. A previously unconsidered, far-field mechanism is utilized which enables chirality to be conveyed from a surrounding chiral molecular material to a plasmonic resonance of an achiral metallic nanostructure. Our observations break a currently held preconception that optical properties of plasmonic particles can most effectively be manipulated by molecular materials through near-field effects. We show that far-field electromagnetic coupling between a localized plasmon of a nonchiral nanostructure and a surrounding chiral molecular layer can induce plasmonic chirality much more effectively (by a factor of 10³) than previously reported near-field phenomena. We gain insight into the mechanism by comparing our experimental results to a simple electromagnetic model which incorporates a plasmonic object coupled with a chiral molecular medium. Our work offers a new direction for the creation of hybrid molecular plasmonic nanomaterials that display significant chiroptical properties in the visible spectral region.

Keywords:

Chiral; plasmonic; metamaterials; optics; nanostructures