Multiple Fano resonances in spoof plasmon resonators of corrugated cylinder/ring structure

We theoretically investigate the spoof surface plasmon interactions in a composite structure consisting of a corrugated metal cylinder and a grooved ring. We demonstrate that the corrugated cylinder can support multipolar sharp cylinder-like resonances, while the grooved ring can support broad-band cavity-like resonances. These two kinds of spectrally overlapping resonances can interfere and result in multiple Fano resonances in the THz regime. We also demonstrate that the introduction of a defect into the corrugated cylinder can generate more Fano interference features. We hope these multiple Fano resonances could be exploited for planar integrated sensing and biological detection in the THz regime.