This Letter presents a plasmonic nanostructure consisting of a nanodisk and a nanoring. The nanodisk is outside of the nanoring. The quadrupolar, hexapolar, and octupolar resonance modes of the nanoring are excited easily by the bright dipolar mode of nanodisks. This nanostructure shows strong interaction and deep Fano dips. In addition, the resonance frequency, depth, and line width of Fano dips can be tuned by changing the geometrical parameters of the nanodisk and nanoring. These plasmonic nanostructures show both high contrast ratio and high figure of merit. Such characters make them suitable for chemical and biological sensing.
© 2012 Optical Society of America
Original Manuscript: September 18, 2012
Revised Manuscript: October 30, 2012
Manuscript Accepted: November 1, 2012
Published: November 28, 2012
Vol. 8, Iss. 1 Virtual Journal for Biomedical Optics
Y. Zhang, T. Q. Jia, H. M. Zhang, and Z. Z. Xu, "Fano resonances in disk–ring plasmonic nanostructure: strong interaction between bright dipolar and dark multipolar mode," Opt. Lett. 37, 4919-4921 (2012)