Theoretical study of vector-vortex field generated by quasi-periodic planar structure

This study presents a rigorous analysis of the vector-vortex field generated by quasi-periodic planar structure (qpps) based on the vectorial Huygens's principle. This letter focuses on the longitudinal component of electrical fields arising from the qpps. We show theoretically that such component is comparable to transverse components in the near field of qpps. Moreover, we demonstrate that the longitude field is also of vortex, with different topological charge from that by transverse components. Selected results are presented to verify the derived theory.