Author Affiliations

G. P. Banfi,¹ P. Di Trapani,^1* R. Danielius,² A. Piskarskas,^3† R. Righini,⁴ and I. Sa'nta⁴

¹Department of Electronics, University of Pavia, 27100 Pavia, Italy

²Laser Research Center, Vilnius University, Vilnius 2054, Lithuania

³Physikalisches Institut, Universität Bayreuth, 8580 Bayreuth, Germany

⁴European Laboratory for Nonlinear Spectroscopy, 50125 Florence, Italy

^*Present address, Department of Physics, University of Milano at Como, 22100 Como, Italy.

^†Permanent address, Laser Research Center, Vilnius University, Vilnius 2054, Lithuania.