Coupling Surface Plasmon Polariton Modes to Complementary THz Metasurfaces Tuned by Inter Meta‐Atom Distance

Abstract

The authors study the interaction of complementary terahertz (THz) split ring resonators with THz surface plasmon polaritons (SPPs) as a function of the meta‐atom distance. The THz transmission properties of 15 samples for which the array dimensions are varied keeping the resonator shape constant are investigated. The linewidth of the inductive‐capacitive (LC‐)resonance is decreasing with increasing meta‐atom distance, up to the frequency matching with the first SPP‐mode. The SPP‐mode couples to the narrow LC‐resonance leading to an anti‐crossing of the modes. In contrast, the narrow SPP‐mode tunes across the broader dipole‐like mode in orthogonal polarization. The excitation direction of the SPP‐mode is found to lie along the electric field polarization of the THz.