Wide-angle absorption of visible light from simple bilayers.

Color-selective absorption of light is a very significant operation used in numerous applications, from photonic sensing and switching to optical signal modulation and energy harnessing. We demonstrate angle-insensitive and polarization-independent absorption by thin bilayers comprising ordinary bulk media: dielectrics, semiconductors, and metals. Several highly efficient designs for each color of the visible spectrum are reported, and their internal fields' distributions reveal the resonance mechanism of absorption. The proposed bilayer components are realizable, since various physical or chemical deposition methods can be used for their effective fabrication. The absorption process is found to exhibit endurance with respect to the longitudinal dimension of the planar structure, which means that the same designs could be successfully utilized in non-planar configurations composed of arbitrary shapes.