a metamaterial absorber operating in the visible light band based on a cascade structure

In this paper, a broadband and polarization-insensitive metamaterial absorber (ma) operating in the visible light band based on a cascade structure is proposed, and the main structure of ma consists of three metal resonator layers (mrls), a metal reflector at the bottom, and a dielectric substrate between them. each mrl consists of four different resonators. the similar resonator is proportional to the size of the top view in the different mrls. through the different absorption effects generated by different mrls, a ma working in the visible light band is obtained, which can cover 490–825 nm. absorption bandwidth can be expanded by adding different mrls and placing different resonators near the same layer. the center frequency of the absorption spectrum can be controlled by changing the layer distance between different mrls. to better understand the physical mechanism of absorption, the electric and magnetic field intensity distributions, the power flows, and the power loss densities also are investigated. we also found that the better permanence can be obtained with the lower incident angle.