Terahertz vector beams generated by rectangular multilayer transmission metasurface

We propose a multilayer unit structure with an “H” shape to construct a vector beam metasurface generator. Based on the principle that half-wave plate can modulate and change the polarization state of linearly polarized incident waves, we have designed a metasurface composed of rectangular units, which can convert linearly polarized beams into azimuthally or radially polarized vector beams at 0.1 THz. The theoretical transmission efficiency is about 60.92 %.We also have prepared a sample of the vector beam generating metasurface by printed circuit board (PCB) technology, and tested the intensity distribution and polarization state of the transmitted beam on the self-built terahertz testbed. The vector beam metasurface realizes the miniaturization and integration characteristics of the device, which has potential applications in microscopic imaging, biophotonics, quartentum information, laser acceleration, micromachining, and other fields.