Chiroptical hot spots in twisted nanowire plasmonic oscillators

We image the chiroptical response of crossed nanowire junctions as a function of the vertical offset between the nanowires and the incident wavelength. These samples show chiroptical hot spots with strongly localized circular differential scattering at the nanowire crossing points. These chiroptical hot spots are not apparent in the spatially averaged spectra. The sign and magnitude of the chiroptical enhancement show a complex dependence on sample geometry, which we reproduce with a fully retarded analytical scattering model. These results suggest strategies for engineering devices with enhanced chiral light-matter interactions. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4789529]