Induced chirality through electromagnetic coupling between chiral molecular layers and plasmonic nanostructures

Abdulrahman, N.A., Fan, Z., Tonooka, T., Kelly, S.M. , Gadegaard, N. , Hendry, E., Govorov, A.O. and Kadodwala, M. (2012) Induced chirality through electromagnetic coupling between chiral molecular layers and plasmonic nanostructures. Nano Letters, 12(2), pp. 977-983. (doi: 10.1021/nl204055r)

Abstract

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 regionWe 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.

• Item Type: Articles (Letter)
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Kadodwala, Professor Malcolm and Kelly, Dr Sharon and Abdulrahman, Mrs Nadia and Gadegaard, Professor Nikolaj
• Authors: Abdulrahman, N.A., Fan, Z., Tonooka, T., Kelly, S.M., Gadegaard, N., Hendry, E., Govorov, A.O., and Kadodwala, M.
• College/School: College of Science and Engineering > School of Chemistry; College of Medical Veterinary and Life Sciences > School of Molecular Biosciences
• Journal Name: Nano Letters
• ISSN: 1530-6984
• ISSN (Online): 1530-6992
• Published Online: 20 January 2012