Highly sensitive tunable terahertz absorber for biosensing applications

Abstract

A multicontrollable terahertz perfect absorber has been proposed and demonstrated numerically through an L-shaped metasurface tri-layer structure. The proposed tri-layer structure comprises a top L-shaped InAs layer and gold ground plane separated by a dielectric polyimide layer which shows a perfect absorption of more than 99.8% with the application of magnetic field from 0.5–0.8 T along with a higher tunability rate of 0.76 THz/T in the frequency spectrum. The multicontrollability and tunability in the frequency response are achieved by the application of a magnetic field as well as the geometrical rotation of meta-atom. Thus, the proposed structure act as a bicontrollable metasurface providing an efficient approach for control over the maximum absorptance frequency. Furthermore, the performance of the proposed absorber shows greater applicability for the bio-chemical sensors with a high value of sensitivity of around 1109 GHz/RIU for the detection of different chemicals, 1012 GHz/RIU for different pathogens, and 1066 GHz/RIU for different hemoglobin concentrations. Thus, the proposed metasurface provides a bicontrollable approach for efficient absorption and prevents transmission as well as acts as multifunctional metasurface which provides potential applications in designing bio-chemical sensors at terahertz frequency regimes.