Chapter 12 High-Charge XUV Vortex Beam: Generation and Hartmann Wavefront Sensor Characterization F. Sanson, A. K. Pandey, F. Harms, G. Dovillaire, E. Baynard, J. Demailly, O. Guilbaud, B. Lucas, O. Neveu, E. Papagionnouli, M. Pittman, D. Ros, M. Richardson, E. Johnson, W. Li, Ph. Balcou and S. Kazamias Abstract In this paper, we present the characterization of high charge vortex struc- ture of an OAM beam produced through high-harmonic generation in a rare gas using an XUV Hartmann wavefront sensor. We show that the phase-matched absorption limited high-harmonic generation is able to retain the high-charge vortex structure of the XUV beam even in a rather long (1 cm) generation medium. Additionally, our recent results on the influence of infrared driver wavefront quality on the character- istics of XUV vortex beam are presented. F. Sanson (B ) · A. K. Pandey · J. Demailly · O. Guilbaud · B. Lucas · O. Neveu · E. Papagionnouli · D. Ros · S. Kazamias Laboratoire de Physique des Gaz et des Plasmas, Université Paris-Saclay (UMR-CNRS 8578), Bat 210, Rue Becquerel, F-91405 Orsay, France e-mail: fabrice.sanson@u-psud.fr F. Sanson Amplitude Laser Group, Scientific Business Unit-Lisses Operations, 2/4 Rue du Bois Chaland, 91090 Lisses, France F. Harms · G. Dovillaire Imagine Optic, 18, rue Charles de Gaulle, 91400 Orsay, France E. Baynard · M. Pittman LASERIX, Centre Laser Université Paris Sud, FR2764, Université Paris-Saclay (UMR-CNRS 8578), Bat 106, 91405 Orsay, France M. Richardson University of Central Florida, 4304 Scorpius Street, Orlando, FL 32816-2700, USA M. Richardson · Ph. Balcou Centre Laser Intense et Applications, Université de Bordeaux (UMR-CNRS-CEA 5107), Talence, France E. Johnson · W. Li Department of Electrical and Computer Engineering, Clemson University, Clemson, SC 29634, USA © Springer Nature Switzerland AG 2020 M. Kozlová and J. Nejdl (eds.), X-Ray Lasers 2018, Springer Proceedings in Physics 241, https://doi.org/10.1007/978-3-030-35453-4_12 79