Terahertz Far-Field Measurements of a Meta-Atom Composed of Concentric Disk and Ring

Resonance behavior of a single meta-atom composed of concentric disk and ring with inter-bridges embedded in a free-standing metal film was investigated experimentally and numerically. The meta-atom was integrated either in square or in circular aperture aiming to exhibit transparency at the resonant frequency of about 0.35 THz. Transmission of the samples were characterized in far-field considering diffraction effects caused by a sub-wavelength structure dimensions being much smaller than the beam diameter of incident radiation used. These findings have broader implications for understanding mutual coupling, anapole states, and other resonant phenomena in meta-surfaces, opening avenues for advanced applications in THz science and technology.