Ultra-wideband high-efficiency reflective linear-to-circular polarization converter based on metasurface at terahertz frequencies

• Published in: Optics express Vol. 25; no. 22; pp. 27616 - 27623
• Main Authors: Jiang, Yannan, Wang, Lei, Wang, Jiao, Akwuruoha, Charles Nwakanma, Cao, Weiping
• Format: Journal Article
• Language: English
• Published: United States 30-10-2017
• ISSN: 1094-4087; 1094-4087
• 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.