Terahertz metasurface sensor with graphene microstrips for biosensing: modeling and application

Abstract: The study is devoted to development and optimization of a metasurface-based sensor with graphene constituents for potential biosensing applications. A unit cell of the proposed metasurface consists of a thin flexible dielectric substrate layer with a centrally positioned graphene microstrip. As a result of numerical modeling of spectral properties of the metasurface by COMSOL Multiphysics software in terahertz range from 5 to 35 THz the absorption spectrum maxima (resonance modes) are revealed. The following stages of the study demonstrate that placement of a layer of tested liquid sample (water or Bovine Serum Albumin (BSA) solution) on the metasurface causes a low frequency shift of the plasmonic resonance mode chosen for biosensing measurements. This frequency shift, along with the change in the amplitude of the absorption peak, are highly sensitive to the refractive index of the tested liquid sample. The obtained results demonstrate the potential of the developed metasurface-based sensor with graphene microstrips for application as a sensing structure to determine proteins and other biomolecules in liquid samples.