Robust absorption broadband in one-dimensional metallic-dielectric quasi-periodic structure

We demonstrated that a broad and robust absorption band for a wide range of incidence angles and for both polarizations can be realized using a one-dimensional metallic-dielectric quasi-periodic structure, when the thickness of the constituent metal is comparable to its skin depth. The absorptance in such peculiar structure can exceed 99% to meet different applications. Furthermore, employing the effective medium approach, a theoretical expression has been deduced to instruct the working frequency of the absorption band. By tuning the permittivity and thickness of the constituent layers, the robust absorption band can cover the wavelength from the visible to the near-infrared.