Ultrathin and broadband highly efficient terahertz reflective polarization converter based on four L-shaped metamaterials

We propose a simple ultrathin design of reflective linear polarization converter with broadband and high efficiency based on four L-shaped anisotropic metamaterials. Simulated results demonstrate our design can convert a linearly polarized wave to its cross-polarized wave and the polarization conversion ratio over 98% is achieved from 4.2 to 5.2 THz. The further simulated results indicate that the deflection angles relative to y axis have greater impact on the cross-polarization reflection coefficient. Our design will provide an important reference for the practical applications of the metamaterials in polarization manipulation. •The proposed reflective polarization converter is ultra-thin with the thickness of 8 μm has simple geometry.•The conversion bandwidth is 4.2–5.2 THz and the average polarization conversion ratio is greater than 90%.•The average polarization conversion ratio is tolerance to wide incident angles.