Wide-angle and wavelength-independent perfect absorption at metamaterial surfaces

Abstract

In this paper, the reflection and absorption properties of a metamaterial layer on a metallic substrate is investigated theoretically and numerically. Perfect absorption is achieved for any frequency and for any angle of incidence when specified conditions are satisfied. These conditions are as follows:(i) the real permeability Re μ of the metamaterial is very small as compared with the imaginary part Im μ and (ii) the metamaterial thickness is very thin as compared with the wavelength of the incident radiation. Expressions for reflection and absorption coefficients are derived in detail. In the numerical results, the mentioned coefficients are computed and illustrated as a function of angle of incidence when Re μ, Im μ, and metamaterial thickness change.