Universal and waveform-resolving dual pulse reconstruction through interferometric strong-field ionization.

A dual pulse retrieval algorithm is introduced that builds upon time-domain interferometric strong-field ionization to simultaneously reconstruct both involved laser pulses in a waveform-resolved manner. The pulse characterization scheme removes many restrictions posed by former methods, leaving the avoidance of resonant ionization as a single boundary. It is widely and easily applicable at low cost and effort for common attosecond beamlines and allows for the robust and accurate in-situ retrieval of two unknown laser fields. For spectrally similar pulses, our method can also extract the carrier-envelope phase of both waveforms. Furthermore, it enables the accurate envelope measurement of ultraviolet laser pulses without any dispersive media, using much longer, commonly available pulses in the infrared. The new technique is therefore ideally suited for the characterization of resonant dispersive waves.