Nonresonant anisotropic metamaterials (AMMs), such as nanotube arrays, can be applied to achieve broadband absorption of electromagnetic (EM) waves. However, the AMMs should be very thick ($\sim 1000$ wavelengths) to attain high absorption. Here, we propose that using a slanted or corrugated metallic mirror, a thin AMM ($\sim 3$ wavelengths) is sufficient to obtain high absorption in a wide wavelength range (absorption $>87\%$ for wavelengths of $0.5–3\mu \text{m}$) and over a wide angular range. Unlike common absorptions, EM waves in an ambient medium (air) is first coupled with a propagating wave in the AMM and is then converted into a lossy wave by mirror reflections.

• Received 18 April 2009

DOI:https://doi.org/10.1103/PhysRevB.80.125103