Generation of high-OAM ultraviolet twisted light for RF-photoinjector applications
Abstract
The generation of relativistic vortex electron beams via photoemission requires ultraviolet laser beams with well-controlled orbital angular momentum (OAM) and compatibility with radio-frequency (RF) photoinjector drive-laser systems. High-OAM vortex beams at a wavelength of 266 nm are generated using three fabricated diffractive optical elements integrated into an operational photoinjector beamline: a reflective fork grating, a high-topological-charge spiral phase plate, and binary axicons. The spiral phase plate produces a high-purity Laguerre-Gaussian mode with an OAM of l = 64 and a conversion efficiency of 80%, whereas binary axicons generate low-divergence quasi-Bessel beams forming a superposition of multiple OAM states with a finite OAM bandwidth imposed by their binary phase structure. Fork gratings provide flexible access to lower OAM values and enable robust modal diagnostics. The generated beams are characterized using cylindrical-lens mode conversion and radial intensity analysis, demonstrating practical control of both the OAM content and spectral bandwidth of ultraviolet structured light for accelerator-based applications.
Keywords
Cite
@article{arxiv.2512.08442,
title = {Generation of high-OAM ultraviolet twisted light for RF-photoinjector applications},
author = {A. S. Dyatlov and D. M. Dolgintsev and V. V. Gerasimov and V. V. Kobets and V. P. Nazmov and M. A. Nozdrin and A. N. Sergeev and D. S. Shokin and K. E. Yunenko and D. V. Karlovets},
journal= {arXiv preprint arXiv:2512.08442},
year = {2026}
}