Metasurface-based half-wave plate

Half-wave plates (HWPs) are used to rotate the polarization state of linearly polarized light, and to switch the handedness of circularly polarized light. An ultrathin metasurface comprised nano-patch antennas and covered with amorphous Silicon is designed to perform as a half-wave plate at infrared frequencies. The design is fabricated using nanolithography techniques and its performance is measured by FTIR. A 30% throughput with less than 1% background noise is achieved in converting the polarization state. A good agreement is obtained between numerical and experimental results.