Polarization customization in all-dielectric terahertz polarizers

In the conventional optical systems, a series of polarizers, e.g., half-wave plates, and quarter-wave plates are used to control polarized wave. Here, we propose an innovative strategy to convert arbitrary polarization states to specific multiple polarization states by applying the cluster composed four meta-atoms on a monolayer all-dielectric metasurface. Two types of functional terahertz metalenses with customized polarization were designed. The first metalens can engender orthogonal circularly polarized waves under unpolarized wave incidence, while the second metalens can generate multiple polarization including co-polarization and cross-polarization to the incidence, the right-hand circular polarization and left-hand circular polarization. We anticipate such polarization customization scheme can be employed to develop various terahertz metalenses for potential applications in the fields of optical communication, optical sensing, biological imaging, and quantum optics.