Plasmon-induced anti-transparency modes in metasurface

We investigate plasmon-induced anti-transparency (PIAT) modes with a metallic metasurface on a dielectric substrate through the finite-element method. Multiple spectral splits are achieved by breaking the symmetry of square-ring resonators. The asymmetry of the structure is attained by incorporating cuts in the rings and increasing displacement of cuts in opposite directions. The high asymmetry decreases the spectral width and enhances the intensity of PIAT resonances. A unified mechanism for generating the PIAT resonances and plasmon-induced transparency (PIT) resonances is studied and agrees with the simulation results. These resonances are highly sensitive to the type of background materials and can be used for detecting cancerous and healthy tissues. A high figure-of-merit (FoM) of 808 is calculated for biosensing. The multiple high-quality factor resonances can also be used for optical filters (band-stop filtering for PIAT modes and band-pass filtering for PIT modes), slow light devices, and switching.