Jiang Yannan, Wang Lei, Wang Jiao, Akwuruoha Charles Nwakanma, Cao Weiping
Opt Express. 2017 Oct 30;25(22):27616-27623. doi: 10.1364/OE.25.027616.
The polarization conversion of electromagnetic (EM) waves, especially linear-to-circular (LTC) polarization conversion, is of great significance in practical applications. In this study, we propose an ultra-wideband high-efficiency reflective LTC polarization converter based on a metasurface in the terahertz regime. It consists of periodic unit cells, each cell of which is formed by a double split resonant square ring, dielectric layer, and fully reflective gold mirror. In the frequency range of 0.60 - 1.41 THz, the magnitudes of the reflection coefficients reach approximately 0.7, and the phase difference between the two orthogonal electric field components of the reflected wave is close to 90° or -270°. The results indicate that the relative bandwidth reaches 80% and the efficiency is greater than 88%, thus, ultra-wideband high-efficiency LTC polarization conversion has been realized. Finally, the physical mechanism of the polarization conversion is revealed. This converter has potential applications in antenna design, EM measurement, and stealth technology.
电磁波的极化转换，尤其是线极化到圆极化（LTC）的极化转换，在实际应用中具有重要意义。在本研究中，我们提出了一种基于太赫兹波段超表面的超宽带高效反射式LTC极化转换器。它由周期性单元组成，每个单元由双分裂谐振方环、介质层和全反射金镜构成。在0.60 - 1.41太赫兹的频率范围内，反射系数的幅值约为0.7，反射波两个正交电场分量之间的相位差接近90°或 -270°。结果表明，相对带宽达到80%，效率大于88%，从而实现了超宽带高效LTC极化转换。最后，揭示了极化转换的物理机制。该转换器在天线设计、电磁测量和隐身技术等方面具有潜在应用。
