Generation of cylindrical vector vortex beams with high purity by using cascaded all-dielectric metasurfaces

In this paper, we propose an efficient approach to generate cylindrical vector vortex beams by cascading the three all-dielectric metasurfaces. The cascaded metasurfaces are composed of 21x21 array units, operate at 1550 nm and are capable of generating the cylindrical vector vortex beams with topological charges of +/- 1 and polarization orders of +/- 1 under the incidence of circularly polarized light. Mode purity of the cylindrical vector vortex beam is 81.71% calculated by numerical simulation. Our design has characteristics of high purity, compact and easy-fabrication and may be a potential candidate in integrated optical system in future.