Terahertz vector Bessel beams based on all-dielectric metasurface.

We design an all-dielectric silicon metasurface adopting an elliptical-cylindrical unit structure. In the case of circularly polarized light incidence, we can obtain terahertz vector Bessel beams with radial or azimuthal polarization characteristics. We demonstrate that the spatial position polarization control of the beam can be achieved by rotating the unit structure with quarter-wave plate function. In addition, the transmission phase is used to offset the extra phase brought by the polarization control, and the function of converting the left-handed or right-handed circularly polarized incident light into a radially or azimuthally polarized Bessel beam is successfully realized at the frequency of 0.71 THz. This research provides feasibility for the generation of vector Bessel beams in the terahertz band. [ABSTRACT FROM AUTHOR]