Anti-crossings and strong couplings in plasmonic Fano resonances

In this talk, we report our recent studies on anti-crossings and strong couplings between triple Fano resonances in a 3D metamaterial (MM). The 3D MMs are formed by integrating vertical asymmetric split-ring-resonators (aSRRs) along a planar metallic hole array with extraordinary optical transmission (EOT) built by means of homemade focused-ion-beam (FIB) folding technique. In such a configuration, the plasmonic system stably supports triple Fano resonance states. More importantly, the induced Fano resonances are widely tunable and strong couplings among triple Fano resonances occurs during the tuning process, which are well verified in both simulations and experiments. These 3D MMs with significant and robust Fano resonances exhibit an extremely high sensitivity to refractive index of the environments in the near infrared wavelength region.