Author Affiliations

S. Banerjee,² M. Baudisch,³ J. Biegert,^3,4 A. Borot,⁵ A. Borzsonyi,⁶ D. Charalambidis,^1,7,8 T. Ditmire,⁹ Zs. Diveki,^1,10 P. Dombi,^1,11,12 K. Ertel,² M. Galimberti,² J. A. Fülöp,^1,13 E. Gaul,⁹ C. Haeffner,¹⁴ M. Hemmer,³ C. Hernandez-Gomez,² M. Kalashnikov,^1,15 D. Kandula,¹⁵ A. P. Kovacs,⁶ R. Lopez-Martens,^1,5 P. Mason,² I. Márton,¹¹ I. Musgrave,² K. Osvay,^1,6 M. Prandolini,¹⁶ E. Racz,^1,17 P. Racz,¹¹ R. Riedel,¹⁶ I. N. Ross,² J.-P. Rosseau,⁵ M. Schulz,¹⁸ F. Tavella,¹⁶ A. Thai,³ and I. Will¹⁵

¹ELI-Hu Nkft, Dugonics ter 13, Szeged 6720, Hungary

²Central Laser Facility, Rutherford Appleton Laboratory, Chilton, Didcot, U.K.

³ICFO Institut de Ciencies Fotoniques, 08860 Castelldefels, Barcelona, Spain

⁴ICREA–Institució Catalana de Recerca i Estudis Avançats, 08010 Barcelona, Spain

⁵Laboratoire d’Optique Appliquee, ENSTA ParisTech, Ecole Polytechnique CNRS UMR 7639, Palaiseau, France

⁶University of Szeged, Szeged, Hungary

⁷FORTH, P.O.Box 1527, GR-71110 Heraklion, Crete, Greece

⁸Univ. of Crete, Dept Phys, P.O.Box 2208, GR-71003 Heraklion, Crete, Greece

⁹University of Texas, Austin, TX, USA

¹⁰Imperial College, London, UK

¹¹Wigner Research Centre for Physics, Budapest, Hungary

¹²Max-Planck Institut für Quantenoptik, Garching, Germany

¹³MTA-PTE High-Field THz Research Group, Pecs, Hungary

¹⁴Lawrance Livermore National Laboratory, Livermore, CA, USA

¹⁵Max-Born-Institut, D-12489 Berlin, Germany

¹⁶Helmholtz Institute Jena, Fröbelstieg 3, Jena D-07743, Germany

¹⁷Obuda University, Budapest, Hungary

¹⁸Deutsches Elektronen Synchrotron, Notkestrasse 85, Hamburg D-22607, Germany