Abstract
We propose a model taking into account the periodic spatial modulation of a doped gra- phene sheet conductivity when it is placed in the vicinity of a dielectric grating. We then compute the absorption and study the excitation of surface plasmons on such a structure. We show that it is possible to excite surface modes leading to very high absorption. Our findings could be of interest in the design of graphene-based plasmonic devices and sensors working in the infra-red and the terahertz regions of the electromagnetic spectrum.