Wide-angle, polarization-independent and dual-band infrared perfect absorber based on L-shaped metamaterial

We propose a wide-angle, polarization-independent and dual-band infrared perfect metamaterial absorber made of double L-shaped gold patches on a dielectric spacer and opaque gold ground layer. Numerical and experimental results demonstrate that the absorber has two near-unity absorption peaks, which are result from magnetic polariton modes generated at two different resonant wavelengths. In addition, the proposed structure also shows good absorption stability in a wide range of incident angles theta for both TE and TM incidences at azimuthal angle phi = 0 degrees. Moreover, we demonstrate that such structure has good absorption stability for a wide range of azimuthal angles due to the excitation of perpendicular magnetic polariton modes within the asymmetric double L-shaped structure. Such structure will assist in designing magnetic polaritons absorbing element for infrared spectroscopy and imaging.