Tunable graphene based plasmonic absorber with grooved metal film in near infrared region

In this paper, we have proposed a graphene based absorber with two absorption peaks at near infrared wavelengths. The metal-graphene nanostructure is composed of a single layer of graphene on a metal film with L-shaped grooves. The results show that by utilizing only one graphene layer the absorption of the structure is increased to more than 0.9 due to the localized surface plasmon resonance (LSPR) in the grooves that amplifies the interaction of light and graphene. We have shown that the full width at half maximum (FWHM) of the absorber is enhanced by decreasing the perpendicular L-shaped grooves length. Also, the absorption spectrum of the proposed structure can be tuned by changing the geometric parameters and chemical potential of graphene.