Broadband Terahertz Metamaterial Absorber Based on Asymmetric Resonators With Perfect Absorption

In this paper, a broadband terahertz (THz) metamaterial absorber using asymmetric split ring resonator (ASR) was designed, fabricated, and characterized. By breaking the symmetry of a split ring resonator, two asymmetric resonances are excited from a dipole resonance, which enhance both the absorption and <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">Q</tex></formula> -factor. With the integration of four different ASRs into one unit cell, a broadband absorber experimentally obtained a 0.82-THz bandwidth with absorptivity of more than 0.9, which is 3.4 times as wide as the 0.24-THz bandwidth of the symmetric dipole peak. The proposed broadband absorber has great application potentials in the THz spectroscopy, imaging, and sensing.