Bidirectional visible light absorber based on nanodisk arrays

A perfect bidirectional broadband visible light absorber composed of titanium nitride and tungsten nanodisk arrays is proposed. The average absorption of the absorber exceeds 89% at 400 nm–800 nm when light is normally incident on the front-side. Illumination from the opposite direction (back-side) results in absorption of more than 75%. Through the theoretical analysis of the electric and magnetic fields, the physical mechanism of the broadband perfect absorption is attributed to the synergy of localized surface plasmons, propagating surface plasmons, and plasmonic resonant cavity modes. Furthermore, the absorber also exhibits excellent polarization-independence performance and a high angular tolerance of ∼ 30° for both front- and back-side incidence. The designed bidirectional broadband visible light absorber here has wide application prospects in the fields of solar cells and ink-free printing.