Ultra-wideband tunable reflective linear-to-circular polarization converter realized by GST-based metasurface at terahertz frequency

• Published in: Optics communications 2022-03, Vol.506, p.127553, Article 127553
• Main Authors: Cai, GaoFeng, Chen, Jia, Zhou, YuJie, Li, MinHua, Dong, JianFeng
• Format: Article
• Language: English
• Subjects: Metasurface; Polarization; Tunable
• ISSN: 0030-4018; 1873-0310
• DOI: 10.1016/j.optcom.2021.127553

Polarization conversion of electromagnetic wave plays an important role in practical application. In this paper, a terahertz band ultra-wideband tunable linear-to-circular polarization converter based on GST metasurface is proposed. It consists of two triangular metals, a phase change material (GST), a dielectric plate and a metal floor. The proposed polarization converter can convert linearly polarized waves into circularly polarized waves in different frequency bands by controlling the crystallization state of GST through temperature, without the need of re-optimization and remanufacturing structure. It has the characteristics of ultra-wideband and high efficiency. The proposed polarization converter has potential for miniaturization and integration of terahertz systems. •At present, the main method is to combine phase-change materials (PCMs) such as black phosphorus, liquid crystals, VO2, graphene and perovskite with metasurfaces. However, there are few reports on the design of tunable linear-to-circular polarization converter using GST.•In the range of 0–2.10 THz, the LP wave is converted into left-handed circularly polarized (LCP) wave in the frequency band of 0.10–1.95 THz. And it is converted into right-handed circularly polarized (RCP) wave in the frequency band of 2.0–2.08 THz.•In the range of 0.82–1.95 THz and 2.0–2.05 THz, the AR is less than 3 dB, and the relative bandwidth is 86.25% and 2.46%, respectively. The polarization conversion efficiency of the two bands with 3 dB bandwidth is more than 82%.