Total absorption by a low-loss dielectric thin layer on top of a metallic metasurface

The experimental demonstration of the total absorption of electromagnetic P-waves impinging on a low-loss dielectric thin layer covering a patterned metallic surface is here reported. A semi-analytical model has been employed to design a metallic grating of coaxial cavities that enhances the absorbing properties of the dielectric thin layer covering the surface. The experimental characterization of three samples shows that total absorption peaks are obtained at the frequencies predicted by the model. It is also demonstrated that the peak position is tunable with the cavity length.