Abstract
We experimentally control high-order harmonic generation by applying a versatile few-cycle pulse-shape control method: splitting up a single broadband continuous laser spectrum into two sections and applying sub-femtosecond relative time delays. For certain time delays, fractional high-harmonic combs (noninteger harmonics) are generated which we find to result from the controlled interference of two attosecond pulse trains. We also observe time-delay-dependent energy-tunability of the high-order harmonics for an asymmetrically split spectrum consisting of a strong and a weak component. The tuning mechanism is quantitatively understood by the controlled modulation of the instantaneous driver frequency at the peak of the shaped laser pulse.
Original language | English (US) |
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Article number | 121104 |
Journal | Applied Physics Letters |
Volume | 100 |
Issue number | 12 |
DOIs | |
State | Published - Mar 19 2012 |
Externally published | Yes |
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)