An ultra-thin chiral metamaterial absorber with high selectivity for LCP and RCP waves

Abstract

An ultra-thin chiral metamaterial absorber (CMMA) is constructed from twisted 'L-shaped' folded metallic wires. In particular, it has high selectivity for left-handed and right-handed circular polarized (LCP and RCP) incident waves, which is impossible in traditional metamaterial absorbers. The thickness of the CMMA is only 0.8 mm, with absorption of 93.2% for LCP and 8.4% for RCP waves, respectively. This superb performance can be applied in homogeneous circular polarizers for an arbitrarily polarized incident wave with high polarization conversion efficiency. Meanwhile, current distributions, retrieval results and multipole theory have been used in analyzing the absorption mechanism. Microwave experiments are performed to successfully realize these ideas, and measured results are in good agreement with the numerical results.