Chiral Metafoils for Terahertz Broadband High-Contrast Flexible Circular Polarizers

Jianfeng Wu, Binghao Ng, Haidong Liang, Mark B.H. Breese, Minghui Hong, Stefan A. Maier, Herbert O. Moser, Ortwin Hess

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29 Citations (Scopus)


Metamaterial concepts have opened the door to high-optical anisotropy beyond levels of naturally occurring materials but usually with limited spectral bandwidth. Here, we report on the design, realization, and experimental and numerical characterization of broadband chiral metafoils exhibiting at the same time exceptionally high-contrast circular polarization in the THz range. We demonstrate that the observed chirality is achieved by a simple modification of the structure of well-established metafoils, namely, through a shift of interconnecting lines by half a unit cell length between each row. The bandwidth of the observed circular-polarization-selective response is demonstrated to be up to about one octave at a center frequency of 2.4 THz and the ratio of the transmission of oppositely circularly polarized radiation is shown to reach about 700%, with the maximum transmittance being approximately 70%. Although implemented here at THz frequencies, broadband chiral metafoils may be extended to higher infrared and optical frequencies by hot embossing or nanoimprinting. They may be used as circular polarizers and beam stops in THz optical and infrared systems.

Original languageEnglish
Article number014005
JournalPhysical Review Applied
Issue number1
Publication statusPublished - 18 Jul 2014
Externally publishedYes

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