Temporal characterization of attosecond XUV fields

Building on the concepts developed for femtosecond metrology, this paper proposes a unified perspective of different techniques for the temporal characterization of attosecond XUV fields. These techniques rely on the conversion of the field to be characterized into a continuum electron wavepacket replica, through single-photon photoionization of an atom. A dressing laser field is then used as an ultrafast phase modulator on this wavepacket, for instance allowing one to shear or to streak it in energy. We present different ways of using this time-nonstationry filter with a multi-PHz bandwidth to characterize attosecond electron wavepackets, and hence attosecond fields.