Polarization-insensitive ultra-wideband metamaterial absorber comprising different forms of ZrN structures at the metasurface

Ultra-wideband metamaterial absorber comprising zirconium nitride (ZrN)-based metasurface was investigated. In particular, the metasurface had three different kinds of resonating element patterns (composed of ZrN), namely the concentric annular square, circular and triangular air gaps of different samples of ZrN, as distin-guished by the nitrogen content of the medium (i.e., ZrN). Spectral performance of metamaterials was evaluated in terms of absorbance, and it was found that the metasurface structure with annular circular resonating elements provides the best performance owing to high absorbance with relatively stable wideband feature. The perfor-mance of the proposed structures was investigated under varying parametric situations considering the incidence excitations with the transverse electric (TE-) and transverse magnetic (TM-) conditions, and also, the normal and oblique incidence of waves. The nearly-perfect absorption along with the ultra-wideband property of the structure were shown. Apart from this, it also exhibits the polarization-insensitive characteristic regardless of the polarization state as well as polarization angle of the incidence waves. Such a kind of absorber would be useful for antireflection coating and solar energy harvesting applications in a wide spectral range from the visible to far -red regimes of wavelength.

Automated summary

An ultra-wideband metamaterial absorber consisting of a zirconium nitride (ZrN)-based metasurface was investigated. The study found that the metasurface with concentric annular resonating elements exhibited the best performance in terms of absorbance, with a stable wideband feature. The structure demonstrated nearly perfect absorption and polarization insensitivity, making it suitable for antireflection coatings and solar energy harvesting in a wide spectral range.