[1] Tech Univ Berlin, Inst Festkorperphys Optoelect & Quantum Devices, Hardenbergstr 36, D-10623 Berlin, Germany
[2] Tech Univ Berlin, AG Nichtlineare Laserdynam, Inst Theoret Phys, Hardenbergstr 36, D-10623 Berlin, Germany
[3] Univ Coll Cork, Dept Phys, Cork, Ireland
[4] Tyndall Natl Inst, Cork, Ireland
[5] Univ Wurzburg, Tech Phys, D-97074 Wurzburg, Germany
[6] Univ St Andrews, Sch Phys & Astron, SUPA, St Andrews KYI6 9SS, Fife, Scotland
[7] Univ Bourgogne Franche Comte, FEMTO ST Opt Dept, CNRS, UMR 6174, 15B Ave Montboucons, F-25030 Besancon, France