A visible and near-infrared broadband light absorber of cone-shaped metallic cavities

Abstract

Metal-coated moth-eye films display broadband light-absorption (BLA) over the visible (380–780 nm) and near-infrared (780–1000 nm) spectral ranges when illuminated from the rear. The pillars on the moth-eye film function as a template of cone-shaped metallic cavities. The average absorptance is 91% over the visible wavelength range. Calculations based on the finite-difference time-domain method revealed that the high absorptance is due to effective capturing of illuminating light in the cone-shaped metallic cavities. This BLA metamaterial, with dimensions larger than 1 cm2 and fabricated without using any nanofabrication technique, is useful for photonics applications involving, e.g. light-harvesting and light-emission.