Bicontrollable all dielectric metasurface absorber for chemical and biosensing applications

Abstract

A bi-controllable all�dielectric�metasurface�structure is designed at�terahertz, which consists of an InAs micro-cylindrical array on the gold ground plane. The maximum�absorptance�frequency is tunable with the help of an external�magnetic field�and also by geometrical rotation of the�metasurface�as InAs is a gyrotropic material whose property depends on the magnitude and direction of an�external magnetic field. Simulation results indicate that the proposed�metasurface�can achieve an�absorptance�of more than 99 % at 9.756�THz as well as it can provide a high tunability rate of around 2.55�THz�T?1�in lower band and 3.33�THz�T?1�in the upper band frequency spectrum with the application of the�magnetic field. Additionally, the�metasurface�also acts as polarization insensitive when no external�magnetic field�is applied. Furthermore, the maximum absorptance frequency shows sensitivity towards the change in the�refractive index�value of the surrounding medium, thus the metasurface can be used for chemical and biosensing applications. It shows high chemical sensitivity of around 2727�GHz/RIU for the detection of different chemicals and bio sensitivity of 787�GHz/RIU for the detection of various viruses.