Photon acceleration of high-intensity vector vortex beams into the extreme ultraviolet

Extreme ultraviolet (XUV) light sources allow for the probing of bound electron dynamics on attosecond scales, interrogation of high-energy-density matter, and access to novel regimes of strong-field quantum electrodynamics. Despite the importance of these applications, coherent XUV sources remain relatively rare, and those that do exist are limited in their peak intensity and spatio-polarization structure. Here, we demonstrate that photon acceleration of optical laser pulses in the moving density gradient of an electron-beam-driven plasma wave can produce relativistically intense XUV laser pulses that preserve the spatio-polarization structure of the original pulse. Quasi-3D, boosted-frame particle-in-cell simulations show the transition of optical vector vortex pulses with 800-nm wavelengths and intensities below 10¹⁸ W/cm² to XUV vector vortex pulses with 36-nm wavelengths and intensities exceeding 10²⁰ W/cm² over a distance of 1.2 cm. The production of such high-quality, high-intensity XUV vector vortex pulses could expand the utility of XUV light as a diagnostic and driver of novel light–matter interactions.