A multi-band terahertz plasmonic absorber based on fan-like metasurface

A plasmonic absorber composed of a sandwich structure based on a fan-like metasurface with three blades has been proposed. The multiple resonance modes are analyzed based on the finite-difference time-domain (FDTD) method by comparing electric field distributions between the unit of absorber with three blades and one individual blade, which proved that the three blades of metasurface can separately excite three absorption peaks in terahertz (THz) band. The influence of the geometry configurations on the resonance modes have also been studied, including radius of blades, the thickness of the top metal layer, and period of unit. The resonance frequencies can be easily tuned by changing the radius of metasurface unit. The proposed plasmonic absorber has potential for THz imaging and sensing applications.