Polarization-Insensitive Metasurface-Biosensor for Glycosuria Sensing in Terahertz Regime

This work presents a single band metasurface perfect absorber (MPA) with a sharp absorption peak. The MPA resonates at 11.912 THz and provides a fractional bandwidth (FBW) of 0.353% (BW = 0.042 THz), corresponding to 90% absorptivity. Gold has been used as a material to design top metasurface patterns. The symmetricity in the design leads to polarization-insensitivity with respect to incident plane wave. At the same time, the MPA provides a similar absorptivity response under both transverse electric and transverse magnetic polarizations due to the excitation of the orthogonal modes. Further, MPA has been examined for biosensing, i.e., Glycosuria, in this work. For the 0.002 change in the value of the refractive index (n), a 0.0002 THz change in resonance frequency has been observed (Sensitivity = 100 GHz/RIU), which confirms the efficacy of the proposed MPA for biosensing in the terahertz regime.