Nonlinear up-conversion of spatiotemporal vortices into the EUV via high harmonic generation - Martín-Hernández, R; Gui, G; Plaja, L; Kapteyn, HC; Murnane, MM; Porras, MA; Liao, CT; Hernández-García, C (Proceedings Of Spie - The International Society For Optical Engineering, 2025)