We report the first reconfiguration-free temporal characterization of a femtosecond light source spanning more than six octaves, from the ultraviolet (210-220 nm) to the midinfrared (15-16 μm), using the recently developed plasma-induced frequency-resolved optical switching (PI-FROSt) technique. A commercial optical parametric amplifier equipped with harmonic-generation and difference-frequency modules is characterized, including the signal, idler, second-and third-harmonic beams, and mid-infrared extensions. All measurements are performed with the same optical setup and switching medium, without any realignment or change of nonlinear elements. These results establish PI-FROSt as a unique, broadband, phase-matching-free, and damage-free diagnostic tool for ultrafast sources.
Espaignol et al. (Mon,) studied this question.