Triple-band terahertz metamaterial absorber with enhanced sensing capabilities

A triple-band perfect metamaterial absorber was achieved in terahertz regime that is made of asymmetric metallic I-shaped resonator and metallic ground layer with dielectric spacer in the middle. The simulated results show that the absorption device has three resonance modes at frequencies 1.655 THz, 1.985 THz and 2.86 THz with corresponding absorption rate closed to 95%. The origin of the triple-band absorber was investigated by electromagnetic field energy distribution. The absorption performance was further analyzed by the structural parameters to verify the underlying mechanisms of these absorption triple-band. Moreover, we also analyze the sensing performances of the absorber for the refractive index and the thickness of the analyte. Two conventional parameters, the sensitivity and figure of merit (FOM), were used to analyze the proposed design for the sensing performance of the device. The refractive index and thickness sensitivities of sensor are 1.2 THz/RIU and 0.0055 THz/µm, and the FOMs are 24.48 and 0.112 which is higher in magnitude compared to the first two resonant peaks and even higher than the resonance peaks of the previously reported works in terahertz regime. The proposed design has a number of applications in sensing, filter and stealth technology.