  Nanoantenna is one of the most important optical components for light
harvesting. In this study, we show experimental evidence of interactions
between coupled nanowires by comparing the fluorescence properties of quantum
dots on both non-coupled (single) and coupled (double and triple) nanowire
arrays. The fluorescence intensities are dependent on the excitation
polarization, and most of the emissions are polarized perpendicular to the long
axis of the nanowires. It is interesting that both the excitation polarization
dependent enhancement and the fluorescence polarization effect are more
pronounced for coupled nanowires. Our theoretical analysis indicates the above
phenomena can be ascribed to the dipolar plasmon from the nanowire antennas.
Our investigations demonstrate a potential method to control the polarization
of emitters using coupled nanowire arrays.
