Theory of phase characterization of harmonics through interference with the fundamental

We present calculations, based on the solution of the time-dependent Schrödinger equation for the hydrogen atom in a discrete basis demonstrating the possibility of extracting the phase profile of a harmonic through its interference with the fundamental. We examine two aspects of the interference: the generated harmonic radiation and the photoelectron energy spectra (if the harmonic is above the ionization threshold). We have focused on the third and the eleventh harmonics (of a 1.5 eV fundamental), where our results demonstrate a reconstruction of the phase profile with deviations of a few percent, on the basis of the modulation of the radiation. In the case of the 11th harmonic, we have also examined the PES modulation, and the phase profile calculated can be of the same quality, although more sensitive.