Spatial contributions of electron trajectories to high-order-harmonic radiation originating from a semi-infinite gas cell

Martin Kretschmar,1,2 Carlos Hernández-Garcı́a,3 Daniel S. Steingrube,1,2 Luis Plaja,3 Uwe Morgner,1,2 and Milutin Kovačev1,2 1Leibniz Universität Hannover, Institut für Quantenoptik, Welfengarten 1, D-30167 Hannover, Germany 2QUEST, Centre for Quantum Engineering and Space-Time Research, Welfengarten 1, D-30167 Hannover, Germany 3Grupo de Investigación en Óptica Extrema, Universidad de Salamanca, E-37008 Salamanca, Spain (Received 6 March 2013; published 8 July 2013)