Investigation on the role of the dielectric loss in metamaterial absorber.

The authors report a metamaterial (MM) consisting of cut-wire structures which shows near-perfect absorption at microwave frequencies. Experimental results show slight lower performance than simulation. The analysis of the spectra and retrieved electromagnetic parameters demonstrate that the mismatch is attributed to the considerable influence of the dielectric loss on the strength of the electric and magnetic resonances, which largely determines the ability of the MM absorber. Such dependence on dielectric loss provides an important clue for the design of MM absorber aiming at specific applications where high efficiency energy collection in dielectric is needed.

Mixed plasmons coupling for expanding the bandwidth of near-perfect absorption at visible frequencies.

We theoretically investigate the electromagnetic response of mixed-size sub-wavelength square hole array (M-SHA) combined with thick metal layer (TML). Near-perfect absorption with bandwidth about 17 nm is firstly observed. Field distribution and dispersion relationship indicate that mixed surface plasmons (M-SPs) coupling is supported by M-SHA and TML. The absorption band is proved to be dominated by M-SPs coupling.

Expanding the band of negative permeability of a composite structure with dual-band negative permeability.

We provide a design of a metallic composite structure, which simultaneously shows dual-band negative permeability (DNP) in two optical ranges. Numerical simulation demonstrates that different shifting of the two magnetic resonances can be observed. This structure property allows the realization of a wide range of negative permeability covering near-infrared (NIR) and visible ranges simultaneously. The alterability of the two neighboring negative permeability would provide a way to realize an effective pass-band of a meta-material with negative permeability at optical frequencies.