Tunable plasmon resonance in the nanobars and split ring resonator(SRR) composite structure

•The transmission spectra are highly tunable as the geometric parameters modifying.•When the gap distance between the two bars is small, a new dip and peak will exist.•When introducing asymmetry to the SRR, a new sharp peak accompany with a dip exists.•We also find that the proposed structures with sensing sensitivity of ~467 nm/RIU.

We have proposed a multi-band metamaterials composed of bars and planer SRR. There are three sharp peaks in the transmission spectra in the visible and near-infrared region, we find that the transmission spectra are highly tunable as the coupling and geometric parameters modifying, especially the third peak in the near-infrared region. When the gap distance between the two nanobar g1<14 nm, the original first peak will split, a new dip and peak will exist, which is results from the high-order plasmon resonance. When introducing asymmetry to the planer SRR, a new sharp peak accompany with a new sharp dip exists in the original second peak, which is originated from the strong electric field resonance. We also find that the proposed structures with sensing sensitivity of ~467 nm/RIU, which can be used for plasmonic sensor.