title: Attosecond extreme ultraviolet vortices from high-order harmonic generation.
abstract: We present a theoretical study of high-order harmonic generation (HHG) and propagation driven by an infrared field carrying orbital angular momentum (OAM). Our calculations unveil the following relevant phenomena: extreme-ultraviolet harmonic vortices are generated and survive to the propagation effects, vortices transport high-OAM multiples of the corresponding OAM of the driving field and, finally, the different harmonic vortices are emitted with similar divergence. We also show the possibility of combining OAM and HHG phase locking to produce attosecond pulses with helical pulse structure.
authors.affiliation: Grupo de Investigación en Óptica Extrema, Universidad de Salamanca, E-37008 Salamanca, Spain and JILA and Department of Physics, University of Colorado at Boulder, Boulder, Colorado 80309-0440, USA.
authors.forename: Carlos
authors.initials: C
authors.lastname: Hernández-García
authors.forename: Antonio
authors.initials: A
authors.lastname: Picón
authors.forename: Julio
authors.initials: J
authors.lastname: San Román
authors.forename: Luis
authors.initials: L
authors.lastname: Plaja