We report on directionality of a novel optical nanoantenna composed of three gold nanodisks ultracompactly arranged in the end-fire configuration. It is found that the emission of a local light source can be remarkably directed and switched based on its color between two opposite directions. The quasi-static approximation is employed to theoretically model the optical properties of the nanostructure and to investigate the observed phenomenon. The proposed nanoantenna enhances and directs the yellow-color toward the forward-direction, and, in contrast, the red-color toward the backward direction. This unique color-switching property is studied in terms of the strong plasmonic interactions of the nanodisks and the resulting hybridized modes of the nanoantenna.
© 2012 Optical Society of America
Original Manuscript: January 30, 2012
Manuscript Accepted: March 23, 2012
Published: May 22, 2012
S. H. Alavi Lavasani and Tavakol Pakizeh, "Color-switched directional ultracompact optical nanoantennas," J. Opt. Soc. Am. B 29, 1361-1366 (2012)