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.

References in corpus (11)

• Theory and applications of free-electron vortex states
• High-dimensional quantum gates using full-field spatial modes of photons
• The Quantum Twisting Microscope
• A novel vortex generator and mode converter for electrons
• Polarized electron-beam acceleration driven by vortex laser pulses
• Mapping spin-polarised transitions with atomic resolution
• Full-field mode sorter using two optimized phase transformations for high-dimensional quantum cryptography
• Quantum mechanical formulation of the Busch theorem
• Generation of vortex electrons by atomic photoionization
• Generation of Deep Ultraviolet Optical Vortices via Amplitude and Phase Spiral Zone Plates
• Diffraction by Circular and Triangular Apertures as a Diagnostic Tool of Twisted Matter Waves