▎ 摘　　要

We demonstrate that a broadband single-layered graphene absorber can be obtained in the THz range using periodic arrays of chemically doped graphene ribbons with gradient width, supported on a dielectric film placed on a thick piece of metal. The working bandwidth of 90% absorption for this structure is as high as 1.3 THz with a central frequency of 3 THz. The broadband operation mechanism is a result of the varying continuous plasmon resonances occurring in graphene ribbons with gradient width. The operation wavelength can be expanded to the far-infrared range. (C) 2015 The Japan Society of Applied Physics