Generation of deep ultraviolet vortices via amplitude and phase spiral zone plates

We report the design, fabrication, and demonstration of diffractive optical elements, amplitude, and phase spiral zone plates (SZPs), for generating optical vortices in the deep ultraviolet (DUV) range (260˘266<i>n</i><i>m</i>). Fabricated via photolithography and plasma etching on fused silica, these SZPs efficiently convert Gaussian beams into vortex modes carrying orbital angular momentum. Experiments with a high-power radio-frequency photoinjector laser at Joint Institute for Nuclear Research produced DUV vortices with topological charge <i>ℓ</i>=1. Comparative analysis shows the phase SZP achieves ∼40<i>%</i> conversion efficiency. These results confirm SZPs' potential for DUV light structuring, enabling applications in electron beam shaping and accelerator technologies.