Abstract
The strong coupling between vibrational modes of molecules and surface plasmon resonance (SPR) modes in graphene makes them an ideal platform for biosensor techniques. In this paper, a new optical biosensor for molecule detection based on silver metallic nanoparticles (MNPs) and graphene/gold MNPs in a terahertz frequency range is achieved. It is established that the nonlinear electrical properties of graphene can play a major role in realizing a biosensor for molecule detection. The performance parameters of the proposed device are reported with respect to the chemical potential mu of graphene, noting that the sensitivity of our device passes from 255 nm/RIU (nanometers/refractive index unit) for mu = 1.21 eV to 2753 nm/RIU for mu = 0.21 eV. Finally, this structure exhibits an optical sensing region that can be adjusted to meet the requirements of optical detection.