Third-harmonic generation in disguise of second-harmonic generation revisited: role of thin-film thickness and carrier-envelope phase.

It has previously been reported that a peak at the spectral position of the second harmonic of an excitation laser can be generated in an inversion-symmetric medium in the regime of extreme nonlinear optics and that this peak may be exploited to measure the carrier-envelope phase of the excitation pulse. Here we revisit this phenomenon with regard to reverse engineering the carrier-envelope phase and demonstrate that the thin-film thickness and the incident field can have a drastic influence on pulse propagation, and so the reverse engineering would likely fail.