Polarization independent highly insensitive ultra-wideband absorber for infrared, visible light and ultraviolet region

Abstract

This work proposes a nickel-dielectric-nickel-based superwideband absorber for the infrared, visible, and ultraviolet spectrums. A square ring is loaded with a corner-truncated square patch to form the resonating structure. The absorber measures 25 × 25 × 10.6 nm3 in total. Absorption (A) is above 90 % throughout a frequency spectrum of 136.3564–5407.291 THz (55.48–2200.12 nm), with an average absorption of 96.49 %. Absorption is ≥95 % within the frequency range of 713.12–4684.15 THz (64.04–420.68 nm). The absorber has A ≥ 80 % for incident angle (θ) ≤ 50°. In the operational band, absorption averages 92.39 % at θ = 50° and 86.65 % at θ = 60°. This absorber has volume reduction upto 99.99 % (in terms of λL3, λL is wavelength at cutoff frequency for A ≥ 90 %), A ≥ 90 % ultrawide bandwidth of ∼190 % (for A ≥ 90 %), average A = 96.49 %, polarization insensitiveness, stable A ≥ 80 % for θ ≤ 50°, almost stable absorption performance for ±0.2 nm dimensions variations due to fabrication tolerances.