Observation of high-frequency coherent vibrations with strongly chirped probe pulses

It is nowadays possible to generate, in different spectral ranges, ultrabroadband light pulses with transform-limited (TL) duration corresponding to a few optical cycles. Whenever broadband pulses are employed, the dispersion experienced by the pulses causes a frequency chirp which may severely lengthen their duration and influence time-resolved measurements. While it is well known that the relative weight of ground-state versus excited-state oscillations can be controlled by the chirp in the pump pulse, the effects of probe pulse chirp have not been fully investigated. In this paper we show, both theoretically and experimentally, that a pump-probe experiment using strongly-chirped probe pulses can preserve the temporal resolution of the TL pulses.