Design and preparation of a single-band tunable metamaterial absorber in terahertz frequency

A metamaterial-based absorber is designed and measured in the 13–16 THz range. An absorption peak of 93% amplitude is achieved at resonance frequency 14.2 THz, which is excited by the bright-bright modes coupling effect. In the first set of experiments, the structural parameter D is reduced from $26\mu m$ to $25.6\mu m,$ resulting in this absorption peak being enhanced from 93% to 97.2% and the resonance frequency moving from 142.THz to 14.65 THz. In the second set of experiments, the thickness of SU-8 layer is increased from $2\mu m$ to $3\mu m,$ resulting in this absorption peak being increased to 99.1% and the resonance frequency shifting 14.05 THz when the thickness of SU-8 layer is increased from $2\mu m$ to $3\mu m.$ When the incidence angle of electromagnetic wave reaches 75, up to 85% absorption rate is obtained. Since the STO layer reveals the temperature-dependent property, the resonance frequency can be controlled by changing the ambient temperature. (paper)