Two Fano resonances are theoretically predicted in a single defect nanocavity, consisting of a rectangular cavity with a small stub defect, side-coupled with a plasmonic waveguide. These two Fano resonances are found to originate from two different mechanisms. One is caused by the excitation of a high-order resonant mode in the rectangular cavity owing to the structural breaking, and the other is attributed to the inherent resonant mode in the small stub defect. The narrow high-order mode and inherent mode couple with the broad low-order resonant mode in the rectangular cavity, giving rise to two Fano resonances. Because of the different origins, these two Fano resonances exhibit quite different responses to the variations of the structural dimensions. This has important applications in highly sensitive and multiparameter sensing in the complicated environments.
© 2013 Optical Society of America
Optics at Surfaces
Original Manuscript: September 30, 2013
Revised Manuscript: November 20, 2013
Manuscript Accepted: November 22, 2013
Published: December 19, 2013
Jianjun Chen, Chengwei Sun, and Qihuang Gong, "Fano resonances in a single defect nanocavity coupled with a plasmonic waveguide," Opt. Lett. 39, 52-55 (2014)