Lower-order-symmetry induced bandwidth-controllable terahertz polarization converter. (13th October 2017)

• Record Type: Journal Article
• Authors: Zang, XiaoFei; Liu, Suji; Cheng, QingQing; Xie, JingYa; Zhu, YiMing; Wang, YaJun
• Is Part Of: Journal of optics. Volume 19:Number 11(2017:Nov.)
• Publication Date: 2017-10-13
• Subjects: ultrathin metasurface -- polarization converter -- bandwidth-controllable; Optics -- Periodicals; 535.05
• DOI: 10.1088/2040-8986/aa8b90
• Languages: English
• ISSNs: 2040-8978

Abstract

Abstract: A transmission-type terahertz (THz) variable-bandwidth cross-polarization converter consisting of single-layer ultrathin metasurface is designed, fabricated and experimentally demonstrated. Both the simulated and measured results show that the bandwidth of linear polarization conversion is about 0.45 THz with a polarization conversion ratio over 90%. Different from the previous studies that mainly contributed to the geometry phase, the excellent characteristic of our designed device results from field-suppression of co-polarization components and field-enhancement of cross-polarization components, respectively. Even more intriguingly, the bandwidth of cross-polarization conversion is tunable by consecutively breaking the symmetry of the micro-structure, that is, the lower-order rotational symmetry, leading to a lower-order-symmetry-controlled THz cross-polarization conversion. Our study is an important step forward in developing compact, integrated, and bandwidth-controllable THz circuits and functional devices.