We theoretically investigate how the generation of attosecond pulses from high-order harmonics can be controlled by using a specially designed sequence of gas jets. We demonstrate that quasi-phase-matching provided by such a multi-jet system can be limited to a sub-femtosecond time window, while adjusting the multi-jet structure allows tuning of the central frequency of the generated isolated attosecond pulse.

It is demonstrated that three-dimensional propagation effects essentially influence attosecond-pulse generation by few-cycle, carrier-envelope-phase stabilized laser pulses used in a polarization-gating configuration. The rapidly changing polarization status gives rise to electron trajectories even longer than those observed with linearly polarized light, but the off-axis contributions and the propagation effects can efficiently act as a filter to

We demonstrate the use of a very simple, compact and versatile method, based on the hollow fiber compression technique, to shorten the temporal length of visible laser pulses of 100÷400 fs to pulse durations shorter than 50 fs. In particular, 200-fs, frequency-doubled, Nd:glass laser pulses (527 nm) were spectrally broadened to final bandwidths as large as 20 nm by nonlinear propagation through an argon-filled hollow fiber. A compact, dispersive,

We argue for a different physical interpretation of the results given in the recent Letter by Painter et al. [Opt. Lett. 31, 3471 (2006)] in which an elongated Ti:saphire beam with two distinct waists is considered as direct evidence of laser filamentation. As the pulse power is well below the critical power for self-focusing, the authors pleaded for new examination of the n2 value for He. A three-dimensional numerical modeling, using the published