Inversion Method Characterization of Graphene-Based Coordination Absorbers Incorporating Periodically Patterned Metal Ring Metasurfaces.

In this paper, we propose a tunable coordinated multi-band absorber that combines graphene with metal-dielectric-metal structures for the realization of multiple toward perfect absorption. The parametric inversion method is used to extract the equivalent impedance and explain the phenomena of multiple-peak absorption. With the change of the Fermi level, equivalent impedances were extracted, and the peculiarities of the individual multiple absorption peaks to change were determined.

Ground-plane-less bidirectional terahertz absorber based on omega resonators.

We present a new ultrathin metamaterial that acts as a frequency-selective absorber of terahertz radiation. The absorber is a square array of pairs of omega-shaped micro-resonators made of high-ohmic-loss metal. The metamaterial provides significant suppression of transmitted and reflected radiation in a bidirectional regime (that is, for both forward and backward propagating radiation).

Broadband infrared quarter wave plate realized through perpendicular-to-helical-axis wave propagation in a helix array.

The ability of helix arrays to filter circularly polarized light efficiently when the light propagates parallel to the helical axis has been demonstrated recently. In this Letter, we present a broadband linear-to-circular polarization transformer composed of metal microhelices. The device provides significant transformation performance combined with high transmittance over a broad infrared wave band.