Xu He-Xiu, Wang Guang-Ming, Qi Mei Qing, Cai Tong, Cui Tie Jun
Opt Express. 2013 Oct 21;21(21):24912-21. doi: 10.1364/OE.21.024912.
We propose a kind of chiral metamaterial inspired from the fractal concept. The Hilbert fractal perturbation in the twisted split ring resonator element results in compact metamaterial and breaking mirror symmetry, which readily forms chirality over triple bands. The discrepancy between co-polarization conversion and cross-polarization conversion over multiple bands can be explored for multifunctional devices. A multiband circular polarizer is then numerically and experimentally studied in the X band based on the bilayered twisted Hilbert resonator with mutual 90° rotation. The ability of transforming linearly polarized incident waves to circularly polarized waves is unambiguously demonstrated with high conversion efficiency and large polarization extinction ratio of more than 20 dB across dual bands. Moreover, exceptionally strong optical activity and circular dichroism are also observed.
我们提出了一种受分形概念启发的手性超材料。扭曲裂环谐振器元件中的希尔伯特分形微扰导致超材料结构紧凑并打破镜面对称性，从而在三个频段上轻松形成手性。可以探索多频段上共极化转换和交叉极化转换之间的差异，以用于多功能器件。然后，基于相互旋转90°的双层扭曲希尔伯特谐振器，在X波段对多频段圆极化器进行了数值和实验研究。明确展示了将线偏振入射波转换为圆偏振波的能力，在双频段上具有高转换效率和大于20 dB的大偏振消光比。此外，还观察到了异常强烈的旋光性和圆二色性。
