Ultra-broadband reconfigurable linear-to-circular polarization converter based on metasurface in terahertz frequency

In this paper, an ultra-broadband reconfigurable linear-to-circular polarization converter based on metasurface in terahertz frequency is proposed. The polarization converter is arranged periodically with unit structure composed of anisotropic metal resonant layer, medium and metal floor. The converter can convert linear polarization wave into circular polarization wave in the frequency range of 0.6965THz-1.664THz with axis ratio less than 3dB and relative bandwidth up to 81.97% and the circular polarization wave is right hand. Under 135°-polarized incident wave, ultra-broadband left-hand circular polarization wave can be achieved, which is characterized as the reconfigurable property of the converter. What's more, the converter has excellent properties of simple structure, high efficiency and can maintain good performance under wide incident angle.