1. Department of Physics, Lund University, P.O. Box 118, 22100 Lund, Sweden
2. Université de Bordeaux, CNRS, CEA, Centre Laser Intenses et Applications (CELIA), 43 Rue P. Noailles, 33400 Talence, France
3. Univ Lyon, Univ Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, F-69622 Villeurbanne, France
4. ASML Research, ASML Netherlands B.V., 5504 DR Veldhoven, Netherlands