The generation of attosecond pulses by superposition of high harmonics relies on their synchronization in the emission. Our experiments in the low-order, plateau, and cutoff regions of the spectrum reveal different regimes in the electron dynamics determining the synchronization quality. The shortest pulses are obtained by combining a spectral filtering of harmonics from the end of the plateau and the cutoff, and a far-field spatial filtering that selects a single electron quantum path contribution to the emission. This method applies to isolated pulses as well as pulse trains.

doi.org/10.1103/physrevlett.93.163901
Phys. Rev. Lett.

Mairesse, Y., de Bohan, A., Frasinski, L. J., Merdji, H., Ciubotariu-Dinu, L., Monchicourt, P., … Salières, P. (2004). Optimization of attosecond pulse generation. Phys.Rev.Lett., 93(Article number: 163901), 1–4. doi:10.1103/physrevlett.93.163901