Regensburg 2016 – scientific programme
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O: Fachverband Oberflächenphysik
O 2: Plasmonics and Nanooptics I: Light-Matter Interaction
O 2.5: Talk
Monday, March 7, 2016, 11:45–12:00, S054
Optical rotation reversal and circular dichroism in resonantly and off-resonantly coupled plasmonic nanosystems — •Mario Hentschel1,2, Vivan E. Ferry3, A. Paul Alivisatos1, and Harald Giessen2 — 1Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States — 24th Physics Institute and Research Center SCoPE, University of Stuttgart, Germany — 3Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, United States
In a system consisting of two resonant L-shaped particles we show that the sign of the circular dichroism spectrum in a plasmonic system can be controllably changed through small geometric perturbations that change the energetic ordering of the hybridized modes [1]. This mechanism is distinct from geometrical changes that explicitly change the handedness of the system. Secondly, we investigate the role of resonant coupling in chiral plasmonic systems, and whether the formation of collective plasmonic modes in a handed assembly of metallic nanostructures is a necessary condition for a chiroptical response. We show in experiment and simulation that off-resonant coupling between spectrally detuned nanostructures arranged with structural chirality leads to a clear yet weak chiroptical response [2]. We interpret our results in the framework of scattering between the individual constituents that in turn leads to a chiroptical farfield response. [1] M. Hentschel et al., ACS Photonics 2, 1253 (2015) [2] V. E. Ferry, M. Hentschel, and A. Paul Alivisatos, Nano Lett. 15, DOI 10.1021/acs.nanolett.5b03970