Towards Attosecond Pulses with High Harmonics |
| P. Agostinia, P.M. Paula, P. Bregera, E.S. Tomab, H.G. Mullerb, G. Mullotc, F. Augec and Ph. Balcouc aCommissariat a l'Energie Atomique, Centre d'Etudes de Saclay 91191 Gif sur Yvette, France bFOM AMOLF, Kruislaan 407, 1098 SJ Amsterdam, The Netherlands cLaboratoire d'Optique Appliquee, ENSTA, Ecole Polytechnique CNRS UMR 7639 91761 Palaiseau Cedex, France |
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| The high harmonics produced by focusing an intense femtosecond laser in a gas are theoretically shown to be locked in phase. The physics of this locking is discussed and a new method based on quantum interference in two-photon, two-color ionization allowing to retrieve the relative phase of harmonic pairs is described. The main result is that the 5~harmonics of orders 11-19 produced in argon generate a train of subfemtosecond pulses with a period of 1.35~fs and a duration of 250~attoseconds. |
| DOI: 10.12693/APhysPolA.101.313 PACS numbers: 42.65.Re, 42.65.Ky, 32.80.Rm, 33.60.Cv |