LAUSR

Graphene sheets support surface plasmon polaritons (SPPs) in the terahertz and infrared regimes, resulting from the collective oscillation of Dirac electrons with excited photons. The SPPs in graphene under external strains exhibit anisotropic properties, varying with the magnitude and direction of mechanical deformation. In this study, we propose an mechanical sensor based on the strain-dependent absorption spectrum of infrared light. The setup consists of a monolayer strained graphene sheet suspended over a grating silver substrate. Under a normal incidence, a strong absorption for transverse magnetic polarization is observed, attributed to the excitation of graphene SPPs. Additionally, the resonances of the absorption spectra can be significantly modulated by the magnitude and direction of the applied strains. Finally, the sensitivity and quality of proposed sensors are evaluated under different configurations. For a moderate condition, the figure of merit with respect to the strain deformation can be larger than 20, and such high values are attributed to the intrinsic low loss of graphene sheet. This work paves the way for sensing applications based on the SPPs of strained graphene.