Ionization phase-match gating for wavelength-tunable isolated attosecond pulse generation

Aurélie Jullien (1, 2, 3, 4) , Thomas Pfeifer (2, 3, 4) , Mark J. Abel (2, 3, 4) , P.M. Nagel (2, 3, 4) , M.J. Bell (2, 3, 4) , Daniel M. Neumark (2, 3, 4) , Stephen R. Leone (2, 3, 4)

1 LOA - Laboratoire d'optique appliquée
2 CSD - Chemical Sciences Division [LBNL Berkeley]
3 Department of Chemistry [Berkeley]
4 Department of Physics [Berkeley]

High-order harmonic emission can be confined to the leading edge of an 800 nm driver laser pulse under moderately intense focusing conditions (7×10^14 W/cm^2) (Pfeifer et al. in Opt. Express 15:17120, 2007). Here, the experimentally observed curtailment of harmonic production on the leading edge of the driver pulse is shown to be controlled by an ionization-induced phase-matching condition. The transient plasma density inherent to the process of high-harmonic generation terminates the harmonic emission by an ultrafast loss of phase matching on the leading edge of the laser pulse. The analysis is supported by a reconstruction of the in situ intensity envelope of the driver pulse with attosecond temporal resolution, performed by measurements of the carrier-envelope phase dependence of individual half-cycle harmonic cutoffs. The method opens the way to wavelength-tunable isolated attosecond pulse generation.

Domains: Optics [physics.optics]

Aurélie Jullien, Thomas Pfeifer, Mark J. Abel, P.M. Nagel, M.J. Bell, et al.. Ionization phase-match gating for wavelength-tunable isolated attosecond pulse generation. Applied Physics B - Laser and Optics, 2008, 93 (2-3), pp.433-442. ⟨10.1007/s00340-008-3187-z⟩. ⟨hal-00528366⟩