title: Circular Dichroism in Off-Resonantly Coupled Plasmonic Nanosystems.
abstract: Chiral plasmonic systems have been shown to exhibit large chiroptical responses, much larger than those found in molecular or solid state systems. In this Letter, we investigate the role of resonant coupling in such systems and whether the formation of collective plasmonic modes in a chiral assembly of metallic nanostructures is a necessary condition for chiroptical response. We show in experiment and simulation that off-resonant coupling between spectrally detuned nanostructures arranged with structural chirality leads to a clear but weak chiroptical response. We interpret our results in the framework of scattering between the individual constituents that in turn leads to a chiroptical farfield response. We envision that our results will allow further tuning and manipulation of chiroptical responses in plasmonic systems for tailored chiral light matter interaction.
authors.affiliation: Department of Chemical Engineering and Materials Science, University of Minnesota-Twin Cities , 421 Washington Ave SE, Minneapolis, Minnesota 55455, United States.
authors.forename: Vivian E
authors.initials: VE
authors.lastname: Ferry
authors.affiliation: Materials Science Division, Lawrence Berkeley National Laboratory , 1 Cyclotron Road, Berkeley, California 94720, United States.
authors.forename: Mario
authors.initials: M
authors.lastname: Hentschel
authors.affiliation: Materials Science Division, Lawrence Berkeley National Laboratory , 1 Cyclotron Road, Berkeley, California 94720, United States.|Department of Chemistry, University of California , Berkeley, California 94720, United States.|Department of Materials Science, University of California , Berkeley, California 94720, United States States.|Kavli Energy NanoScience Institute, University of California , Berkeley, California 94720, United States.
authors.forename: A Paul
authors.initials: AP
authors.lastname: Alivisatos
keywords: chirality; circular dichroism; plasmon hybridization; surface plasmons