Design of an Ultrabroadband and High-efficiency Reflective Linear Polarization Convertor at Optical Frequency

Abstract

A simple design of an ultrabroadband and high-efficiency reflective linear polarization convertor is presented in the optical frequency region. This ultrabroadband convertor is formed from the planar anisotropic metasurface using a meander wire structure. The numerical simulation demonstrates that the polarization conversion ratio over 90% is achieved from 181 to 506 THz, which is equivalent to 94.6% relative bandwidth for y -polarized incident lights under normal incidence. Further simulation results show that the high polarization conversion efficiency can be sustained well when the incident angle increases to 45 ${}^{\circ}$ for both transverse electric (TE) and transverse magnetic (TM) modes. By taking advantage of surface current distribution, the physical mechanisms are elucidated in detail. The further theoretical calculation results based on the interference theory are good agreement with the simualtion. Our design provides a unique approach in realizing the polarization manipulation with high performances in the optical frequency region.