Polarization Insensitive and Broadband Terahertz Absorber Using Graphene Disks

We demonstrate design and characterization of a polarization-independent ultra-broadband absorber of light consisting of periodic array of graphene disks on top of a lossless quarter-wavelength dielectric spacer placed on a metallic reflector. The absorber is duly designed based on impedance matching concept by proposing a fully analytical circuit model resulting in a normalized bandwidth of 100 % in the terahertz regime.