Wide band ultrathin polarization insensitive electric field driven metamaterial absorber

摘要

We demonstrate a novel wideband ultrathin polarization insensitive electric field driven metamaterial based dually stacked petal resonator (DSPR) perfect absorber for cloaking, THz imaging and sensing, solar cell, stealth technology, and remote sensing applications. The designed DSPR absorber is composed of a polyimide substrate and gold. The DSPR perfect absorber exhibits 98% absorption fractional bandwidth of 12.8% over a frequency range of 0.591 THz to 0.672 THz. The compact unit cell has 0.29 lambda(o)* 0.29 lambda(o)* 0.06 lambda(o) size, where lambda(o) is the lower absorption peak wavelength. Owing to the symmetric geometry, the DSPR absorption response is polarization insensitive over an extensive range of 90 degrees for both Transverse Electric (TE) and Transverse Magnetic (TM) polarizations. An excellent absorption behavior is perceived over a wide oblique angle of incidence of 75 degrees for both TE and TM polarizations. For an oblique angle of incidence, the proposed structure has interesting features to TE and TM polarizations. A thorough parametric optimization is investigated which elucidates the DSPR response as a function of structural parameters. The physics behind the absorption mechanism is explored by examining the surface current distribution, magnetic field distribution, electric field distribution, power loss density and normalized impedance. Field distributions reveal the existence of Fabry-Perot reflections and electric dipole resonances.