Printed Terahertz Spiral Zone Plate for Vortex Beam Generation

In this work, we fabricated and characterized printed terahertz (THz) spiral zone plates (THz-SZPs). Fabrication has been done using industrial roll-to-roll (R2R) continuous press with a flexography printing unit. From both simulation and experiment results it is seen that, printed spiral zone plates with topological charges, l=1,2, and 3, can convert the Gaussian THz beam into vortex THz beam accordingly with a focal length of 2.0 cm at the operating frequency of 0.36 THz.