Numerical Study on Plasmonic Absorption Enhancement by a Rippled Graphene Sheet

We investigate the absorption property of a single layer of periodically rippled graphene adhering to dielectric substrate. By varying the geometric parameters of the ripple and chemical potential of graphene, the absorption can remarkably exceed that of planar graphene and reaches over 50%. It is found that the absorption peak undergoes a redshift as the ripple height increases. The variation of the incident angle will basically not influence the absorption wavelength but may yield additional absorption peaks due to higher order oscillation. The study reveals the optical response of graphene in the intrinsically nonplanar profile and will benefit to the design of graphene-based absorbers and photodetectors.